publicdata/nist-gov
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
nist-gov/www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero
Scott Williams 4063bef310 Initital commit.
2025-03-05 18:59:57 +00:00

1464 lines
118 KiB
Text
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html lang="en" dir="ltr" prefix="content: http://purl.org/rss/1.0/modules/content/ dc: http://purl.org/dc/terms/ foaf: http://xmlns.com/foaf/0.1/ og: http://ogp.me/ns# rdfs: http://www.w3.org/2000/01/rdf-schema# schema: http://schema.org/ sioc: http://rdfs.org/sioc/ns# sioct: http://rdfs.org/sioc/types# skos: http://www.w3.org/2004/02/skos/core# xsd: http://www.w3.org/2001/XMLSchema# ">
<head>
<meta charset="utf-8" /><script type="text/javascript">(window.NREUM||(NREUM={})).init={ajax:{deny_list:["bam.nr-data.net"]}};(window.NREUM||(NREUM={})).loader_config={licenseKey:"37b7ccb661",applicationID:"1089704227"};;/*! For license information please see nr-loader-rum-1.283.2.min.js.LICENSE.txt */
(()=>{var e,t,r={122:(e,t,r)=>{"use strict";r.d(t,{a:()=>i});var n=r(944);function i(e,t){try{if(!e||"object"!=typeof e)return(0,n.R)(3);if(!t||"object"!=typeof t)return(0,n.R)(4);const r=Object.create(Object.getPrototypeOf(t),Object.getOwnPropertyDescriptors(t)),o=0===Object.keys(r).length?e:r;for(let a in o)if(void 0!==e[a])try{if(null===e[a]){r[a]=null;continue}Array.isArray(e[a])&&Array.isArray(t[a])?r[a]=Array.from(new Set([...e[a],...t[a]])):"object"==typeof e[a]&&"object"==typeof t[a]?r[a]=i(e[a],t[a]):r[a]=e[a]}catch(e){(0,n.R)(1,e)}return r}catch(e){(0,n.R)(2,e)}}},555:(e,t,r)=>{"use strict";r.d(t,{Vp:()=>c,fn:()=>s,x1:()=>u});var n=r(384),i=r(122);const o={beacon:n.NT.beacon,errorBeacon:n.NT.errorBeacon,licenseKey:void 0,applicationID:void 0,sa:void 0,queueTime:void 0,applicationTime:void 0,ttGuid:void 0,user:void 0,account:void 0,product:void 0,extra:void 0,jsAttributes:{},userAttributes:void 0,atts:void 0,transactionName:void 0,tNamePlain:void 0},a={};function s(e){try{const t=c(e);return!!t.licenseKey&&!!t.errorBeacon&&!!t.applicationID}catch(e){return!1}}function c(e){if(!e)throw new Error("All info objects require an agent identifier!");if(!a[e])throw new Error("Info for ".concat(e," was never set"));return a[e]}function u(e,t){if(!e)throw new Error("All info objects require an agent identifier!");a[e]=(0,i.a)(t,o);const r=(0,n.nY)(e);r&&(r.info=a[e])}},217:(e,t,r)=>{"use strict";r.d(t,{D0:()=>m,gD:()=>v,xN:()=>h});r(860).K7.genericEvents;const n="experimental.marks",i="experimental.measures",o="experimental.resources",a=e=>{if(!e||"string"!=typeof e)return!1;try{document.createDocumentFragment().querySelector(e)}catch{return!1}return!0};var s=r(614),c=r(944),u=r(384),l=r(122);const d="[data-nr-mask]",f=()=>{const e={feature_flags:[],experimental:{marks:!1,measures:!1,resources:!1},mask_selector:"*",block_selector:"[data-nr-block]",mask_input_options:{color:!1,date:!1,"datetime-local":!1,email:!1,month:!1,number:!1,range:!1,search:!1,tel:!1,text:!1,time:!1,url:!1,week:!1,textarea:!1,select:!1,password:!0}};return{ajax:{deny_list:void 0,block_internal:!0,enabled:!0,autoStart:!0},distributed_tracing:{enabled:void 0,exclude_newrelic_header:void 0,cors_use_newrelic_header:void 0,cors_use_tracecontext_headers:void 0,allowed_origins:void 0},get feature_flags(){return e.feature_flags},set feature_flags(t){e.feature_flags=t},generic_events:{enabled:!0,autoStart:!0},harvest:{interval:30},jserrors:{enabled:!0,autoStart:!0},logging:{enabled:!0,autoStart:!0},metrics:{enabled:!0,autoStart:!0},obfuscate:void 0,page_action:{enabled:!0},page_view_event:{enabled:!0,autoStart:!0},page_view_timing:{enabled:!0,autoStart:!0},performance:{get capture_marks(){return e.feature_flags.includes(n)||e.experimental.marks},set capture_marks(t){e.experimental.marks=t},get capture_measures(){return e.feature_flags.includes(i)||e.experimental.measures},set capture_measures(t){e.experimental.measures=t},capture_detail:!0,resources:{get enabled(){return e.feature_flags.includes(o)||e.experimental.resources},set enabled(t){e.experimental.resources=t},asset_types:[],first_party_domains:[],ignore_newrelic:!0}},privacy:{cookies_enabled:!0},proxy:{assets:void 0,beacon:void 0},session:{expiresMs:s.wk,inactiveMs:s.BB},session_replay:{autoStart:!0,enabled:!1,preload:!1,sampling_rate:10,error_sampling_rate:100,collect_fonts:!1,inline_images:!1,fix_stylesheets:!0,mask_all_inputs:!0,get mask_text_selector(){return e.mask_selector},set mask_text_selector(t){a(t)?e.mask_selector="".concat(t,",").concat(d):""===t||null===t?e.mask_selector=d:(0,c.R)(5,t)},get block_class(){return"nr-block"},get ignore_class(){return"nr-ignore"},get mask_text_class(){return"nr-mask"},get block_selector(){return e.block_selector},set block_selector(t){a(t)?e.block_selector+=",".concat(t):""!==t&&(0,c.R)(6,t)},get mask_input_options(){return e.mask_input_options},set mask_input_options(t){t&&"object"==typeof t?e.mask_input_options={...t,password:!0}:(0,c.R)(7,t)}},session_trace:{enabled:!0,autoStart:!0},soft_navigations:{enabled:!0,autoStart:!0},spa:{enabled:!0,autoStart:!0},ssl:void 0,user_actions:{enabled:!0,elementAttributes:["id","className","tagName","type"]}}},g={},p="All configuration objects require an agent identifier!";function m(e){if(!e)throw new Error(p);if(!g[e])throw new Error("Configuration for ".concat(e," was never set"));return g[e]}function h(e,t){if(!e)throw new Error(p);g[e]=(0,l.a)(t,f());const r=(0,u.nY)(e);r&&(r.init=g[e])}function v(e,t){if(!e)throw new Error(p);var r=m(e);if(r){for(var n=t.split("."),i=0;i<n.length-1;i++)if("object"!=typeof(r=r[n[i]]))return;r=r[n[n.length-1]]}return r}},371:(e,t,r)=>{"use strict";r.d(t,{V:()=>f,f:()=>d});var n=r(122),i=r(384),o=r(154),a=r(324);let s=0;const c={buildEnv:a.F3,distMethod:a.Xs,version:a.xv,originTime:o.WN},u={customTransaction:void 0,disabled:!1,isolatedBacklog:!1,loaderType:void 0,maxBytes:3e4,onerror:void 0,ptid:void 0,releaseIds:{},appMetadata:{},session:void 0,denyList:void 0,timeKeeper:void 0,obfuscator:void 0,harvester:void 0},l={};function d(e){if(!e)throw new Error("All runtime objects require an agent identifier!");if(!l[e])throw new Error("Runtime for ".concat(e," was never set"));return l[e]}function f(e,t){if(!e)throw new Error("All runtime objects require an agent identifier!");l[e]={...(0,n.a)(t,u),...c},Object.hasOwnProperty.call(l[e],"harvestCount")||Object.defineProperty(l[e],"harvestCount",{get:()=>++s});const r=(0,i.nY)(e);r&&(r.runtime=l[e])}},324:(e,t,r)=>{"use strict";r.d(t,{F3:()=>i,Xs:()=>o,xv:()=>n});const n="1.283.2",i="PROD",o="CDN"},154:(e,t,r)=>{"use strict";r.d(t,{OF:()=>c,RI:()=>i,WN:()=>l,bv:()=>o,gm:()=>a,mw:()=>s,sb:()=>u});var n=r(863);const i="undefined"!=typeof window&&!!window.document,o="undefined"!=typeof WorkerGlobalScope&&("undefined"!=typeof self&&self instanceof WorkerGlobalScope&&self.navigator instanceof WorkerNavigator||"undefined"!=typeof globalThis&&globalThis instanceof WorkerGlobalScope&&globalThis.navigator instanceof WorkerNavigator),a=i?window:"undefined"!=typeof WorkerGlobalScope&&("undefined"!=typeof self&&self instanceof WorkerGlobalScope&&self||"undefined"!=typeof globalThis&&globalThis instanceof WorkerGlobalScope&&globalThis),s=Boolean("hidden"===a?.document?.visibilityState),c=/iPad|iPhone|iPod/.test(a.navigator?.userAgent),u=c&&"undefined"==typeof SharedWorker,l=((()=>{const e=a.navigator?.userAgent?.match(/Firefox[/\s](\d+\.\d+)/);Array.isArray(e)&&e.length>=2&&e[1]})(),Date.now()-(0,n.t)())},687:(e,t,r)=>{"use strict";r.d(t,{Ak:()=>c,Ze:()=>d,x3:()=>u});var n=r(836),i=r(606),o=r(860),a=r(646);const s={};function c(e,t){const r={staged:!1,priority:o.P3[t]||0};l(e),s[e].get(t)||s[e].set(t,r)}function u(e,t){e&&s[e]&&(s[e].get(t)&&s[e].delete(t),g(e,t,!1),s[e].size&&f(e))}function l(e){if(!e)throw new Error("agentIdentifier required");s[e]||(s[e]=new Map)}function d(e="",t="feature",r=!1){if(l(e),!e||!s[e].get(t)||r)return g(e,t);s[e].get(t).staged=!0,f(e)}function f(e){const t=Array.from(s[e]);t.every((([e,t])=>t.staged))&&(t.sort(((e,t)=>e[1].priority-t[1].priority)),t.forEach((([t])=>{s[e].delete(t),g(e,t)})))}function g(e,t,r=!0){const o=e?n.ee.get(e):n.ee,s=i.i.handlers;if(!o.aborted&&o.backlog&&s){if(r){const e=o.backlog[t],r=s[t];if(r){for(let t=0;e&&t<e.length;++t)p(e[t],r);Object.entries(r).forEach((([e,t])=>{Object.values(t||{}).forEach((t=>{t[0]?.on&&t[0]?.context()instanceof a.y&&t[0].on(e,t[1])}))}))}}o.isolatedBacklog||delete s[t],o.backlog[t]=null,o.emit("drain-"+t,[])}}function p(e,t){var r=e[1];Object.values(t[r]||{}).forEach((t=>{var r=e[0];if(t[0]===r){var n=t[1],i=e[3],o=e[2];n.apply(i,o)}}))}},836:(e,t,r)=>{"use strict";r.d(t,{P:()=>c,ee:()=>u});var n=r(384),i=r(990),o=r(371),a=r(646),s=r(607);const c="nr@context:".concat(s.W),u=function e(t,r){var n={},s={},l={},d=!1;try{d=16===r.length&&(0,o.f)(r).isolatedBacklog}catch(e){}var f={on:p,addEventListener:p,removeEventListener:function(e,t){var r=n[e];if(!r)return;for(var i=0;i<r.length;i++)r[i]===t&&r.splice(i,1)},emit:function(e,r,n,i,o){!1!==o&&(o=!0);if(u.aborted&&!i)return;t&&o&&t.emit(e,r,n);for(var a=g(n),c=m(e),l=c.length,d=0;d<l;d++)c[d].apply(a,r);var p=v()[s[e]];p&&p.push([f,e,r,a]);return a},get:h,listeners:m,context:g,buffer:function(e,t){const r=v();if(t=t||"feature",f.aborted)return;Object.entries(e||{}).forEach((([e,n])=>{s[n]=t,t in r||(r[t]=[])}))},abort:function(){f._aborted=!0,Object.keys(f.backlog).forEach((e=>{delete f.backlog[e]}))},isBuffering:function(e){return!!v()[s[e]]},debugId:r,backlog:d?{}:t&&"object"==typeof t.backlog?t.backlog:{},isolatedBacklog:d};return Object.defineProperty(f,"aborted",{get:()=>{let e=f._aborted||!1;return e||(t&&(e=t.aborted),e)}}),f;function g(e){return e&&e instanceof a.y?e:e?(0,i.I)(e,c,(()=>new a.y(c))):new a.y(c)}function p(e,t){n[e]=m(e).concat(t)}function m(e){return n[e]||[]}function h(t){return l[t]=l[t]||e(f,t)}function v(){return f.backlog}}(void 0,"globalEE"),l=(0,n.Zm)();l.ee||(l.ee=u)},646:(e,t,r)=>{"use strict";r.d(t,{y:()=>n});class n{constructor(e){this.contextId=e}}},908:(e,t,r)=>{"use strict";r.d(t,{d:()=>n,p:()=>i});var n=r(836).ee.get("handle");function i(e,t,r,i,o){o?(o.buffer([e],i),o.emit(e,t,r)):(n.buffer([e],i),n.emit(e,t,r))}},606:(e,t,r)=>{"use strict";r.d(t,{i:()=>o});var n=r(908);o.on=a;var i=o.handlers={};function o(e,t,r,o){a(o||n.d,i,e,t,r)}function a(e,t,r,i,o){o||(o="feature"),e||(e=n.d);var a=t[o]=t[o]||{};(a[r]=a[r]||[]).push([e,i])}},878:(e,t,r)=>{"use strict";function n(e,t){return{capture:e,passive:!1,signal:t}}function i(e,t,r=!1,i){window.addEventListener(e,t,n(r,i))}function o(e,t,r=!1,i){document.addEventListener(e,t,n(r,i))}r.d(t,{DD:()=>o,jT:()=>n,sp:()=>i})},607:(e,t,r)=>{"use strict";r.d(t,{W:()=>n});const n=(0,r(566).bz)()},566:(e,t,r)=>{"use strict";r.d(t,{LA:()=>s,bz:()=>a});var n=r(154);const i="xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx";function o(e,t){return e?15&e[t]:16*Math.random()|0}function a(){const e=n.gm?.crypto||n.gm?.msCrypto;let t,r=0;return e&&e.getRandomValues&&(t=e.getRandomValues(new Uint8Array(30))),i.split("").map((e=>"x"===e?o(t,r++).toString(16):"y"===e?(3&o()|8).toString(16):e)).join("")}function s(e){const t=n.gm?.crypto||n.gm?.msCrypto;let r,i=0;t&&t.getRandomValues&&(r=t.getRandomValues(new Uint8Array(e)));const a=[];for(var s=0;s<e;s++)a.push(o(r,i++).toString(16));return a.join("")}},614:(e,t,r)=>{"use strict";r.d(t,{BB:()=>a,H3:()=>n,g:()=>u,iL:()=>c,tS:()=>s,uh:()=>i,wk:()=>o});const n="NRBA",i="SESSION",o=144e5,a=18e5,s={STARTED:"session-started",PAUSE:"session-pause",RESET:"session-reset",RESUME:"session-resume",UPDATE:"session-update"},c={SAME_TAB:"same-tab",CROSS_TAB:"cross-tab"},u={OFF:0,FULL:1,ERROR:2}},863:(e,t,r)=>{"use strict";function n(){return Math.floor(performance.now())}r.d(t,{t:()=>n})},944:(e,t,r)=>{"use strict";function n(e,t){"function"==typeof console.debug&&console.debug("New Relic Warning: https://github.com/newrelic/newrelic-browser-agent/blob/main/docs/warning-codes.md#".concat(e),t)}r.d(t,{R:()=>n})},284:(e,t,r)=>{"use strict";r.d(t,{t:()=>c,B:()=>s});var n=r(836),i=r(154);const o="newrelic";const a=new Set,s={};function c(e,t){const r=n.ee.get(t);s[t]??={},e&&"object"==typeof e&&(a.has(t)||(r.emit("rumresp",[e]),s[t]=e,a.add(t),function(e={}){try{i.gm.dispatchEvent(new CustomEvent(o,{detail:e}))}catch(e){}}({loaded:!0})))}},990:(e,t,r)=>{"use strict";r.d(t,{I:()=>i});var n=Object.prototype.hasOwnProperty;function i(e,t,r){if(n.call(e,t))return e[t];var i=r();if(Object.defineProperty&&Object.keys)try{return Object.defineProperty(e,t,{value:i,writable:!0,enumerable:!1}),i}catch(e){}return e[t]=i,i}},389:(e,t,r)=>{"use strict";function n(e,t=500,r={}){const n=r?.leading||!1;let i;return(...r)=>{n&&void 0===i&&(e.apply(this,r),i=setTimeout((()=>{i=clearTimeout(i)}),t)),n||(clearTimeout(i),i=setTimeout((()=>{e.apply(this,r)}),t))}}function i(e){let t=!1;return(...r)=>{t||(t=!0,e.apply(this,r))}}r.d(t,{J:()=>i,s:()=>n})},289:(e,t,r)=>{"use strict";r.d(t,{GG:()=>o,sB:()=>a});var n=r(878);function i(){return"undefined"==typeof document||"complete"===document.readyState}function o(e,t){if(i())return e();(0,n.sp)("load",e,t)}function a(e){if(i())return e();(0,n.DD)("DOMContentLoaded",e)}},384:(e,t,r)=>{"use strict";r.d(t,{NT:()=>o,US:()=>l,Zm:()=>a,bQ:()=>c,dV:()=>s,nY:()=>u,pV:()=>d});var n=r(154),i=r(863);const o={beacon:"bam.nr-data.net",errorBeacon:"bam.nr-data.net"};function a(){return n.gm.NREUM||(n.gm.NREUM={}),void 0===n.gm.newrelic&&(n.gm.newrelic=n.gm.NREUM),n.gm.NREUM}function s(){let e=a();return e.o||(e.o={ST:n.gm.setTimeout,SI:n.gm.setImmediate,CT:n.gm.clearTimeout,XHR:n.gm.XMLHttpRequest,REQ:n.gm.Request,EV:n.gm.Event,PR:n.gm.Promise,MO:n.gm.MutationObserver,FETCH:n.gm.fetch,WS:n.gm.WebSocket}),e}function c(e,t){let r=a();r.initializedAgents??={},t.initializedAt={ms:(0,i.t)(),date:new Date},r.initializedAgents[e]=t}function u(e){let t=a();return t.initializedAgents?.[e]}function l(e,t){a()[e]=t}function d(){return function(){let e=a();const t=e.info||{};e.info={beacon:o.beacon,errorBeacon:o.errorBeacon,...t}}(),function(){let e=a();const t=e.init||{};e.init={...t}}(),s(),function(){let e=a();const t=e.loader_config||{};e.loader_config={...t}}(),a()}},843:(e,t,r)=>{"use strict";r.d(t,{u:()=>i});var n=r(878);function i(e,t=!1,r,i){(0,n.DD)("visibilitychange",(function(){if(t)return void("hidden"===document.visibilityState&&e());e(document.visibilityState)}),r,i)}},434:(e,t,r)=>{"use strict";r.d(t,{Jt:()=>o,YM:()=>c});var n=r(836),i=r(607);const o="nr@original:".concat(i.W);var a=Object.prototype.hasOwnProperty,s=!1;function c(e,t){return e||(e=n.ee),r.inPlace=function(e,t,n,i,o){n||(n="");const a="-"===n.charAt(0);for(let s=0;s<t.length;s++){const c=t[s],u=e[c];l(u)||(e[c]=r(u,a?c+n:n,i,c,o))}},r.flag=o,r;function r(t,r,n,s,c){return l(t)?t:(r||(r=""),nrWrapper[o]=t,function(e,t,r){if(Object.defineProperty&&Object.keys)try{return Object.keys(e).forEach((function(r){Object.defineProperty(t,r,{get:function(){return e[r]},set:function(t){return e[r]=t,t}})})),t}catch(e){u([e],r)}for(var n in e)a.call(e,n)&&(t[n]=e[n])}(t,nrWrapper,e),nrWrapper);function nrWrapper(){var o,a,l,d;try{a=this,o=[...arguments],l="function"==typeof n?n(o,a):n||{}}catch(t){u([t,"",[o,a,s],l],e)}i(r+"start",[o,a,s],l,c);try{return d=t.apply(a,o)}catch(e){throw i(r+"err",[o,a,e],l,c),e}finally{i(r+"end",[o,a,d],l,c)}}}function i(r,n,i,o){if(!s||t){var a=s;s=!0;try{e.emit(r,n,i,t,o)}catch(t){u([t,r,n,i],e)}s=a}}}function u(e,t){t||(t=n.ee);try{t.emit("internal-error",e)}catch(e){}}function l(e){return!(e&&"function"==typeof e&&e.apply&&!e[o])}},993:(e,t,r)=>{"use strict";r.d(t,{A$:()=>o,ET:()=>a,p_:()=>i});var n=r(860);const i={ERROR:"ERROR",WARN:"WARN",INFO:"INFO",DEBUG:"DEBUG",TRACE:"TRACE"},o={OFF:0,ERROR:1,WARN:2,INFO:3,DEBUG:4,TRACE:5},a="log";n.K7.logging},773:(e,t,r)=>{"use strict";r.d(t,{z_:()=>o,XG:()=>s,TZ:()=>n,rs:()=>i,xV:()=>a});r(154),r(566),r(384);const n=r(860).K7.metrics,i="sm",o="cm",a="storeSupportabilityMetrics",s="storeEventMetrics"},630:(e,t,r)=>{"use strict";r.d(t,{T:()=>n});const n=r(860).K7.pageViewEvent},782:(e,t,r)=>{"use strict";r.d(t,{T:()=>n});const n=r(860).K7.pageViewTiming},344:(e,t,r)=>{"use strict";r.d(t,{G4:()=>i});var n=r(614);r(860).K7.sessionReplay;const i={RECORD:"recordReplay",PAUSE:"pauseReplay",REPLAY_RUNNING:"replayRunning",ERROR_DURING_REPLAY:"errorDuringReplay"};n.g.ERROR,n.g.FULL,n.g.OFF},234:(e,t,r)=>{"use strict";r.d(t,{W:()=>o});var n=r(836),i=r(687);class o{constructor(e,t){this.agentIdentifier=e,this.ee=n.ee.get(e),this.featureName=t,this.blocked=!1}deregisterDrain(){(0,i.x3)(this.agentIdentifier,this.featureName)}}},603:(e,t,r)=>{"use strict";r.d(t,{j:()=>K});var n=r(860),i=r(555),o=r(371),a=r(908),s=r(836),c=r(687),u=r(289),l=r(154),d=r(944),f=r(773),g=r(384),p=r(344);const m=["setErrorHandler","finished","addToTrace","addRelease","recordCustomEvent","addPageAction","setCurrentRouteName","setPageViewName","setCustomAttribute","interaction","noticeError","setUserId","setApplicationVersion","start",p.G4.RECORD,p.G4.PAUSE,"log","wrapLogger"],h=["setErrorHandler","finished","addToTrace","addRelease"];var v=r(863),b=r(614),y=r(993);var w=r(646),R=r(434);const A=new Map;function E(e,t,r,n){if("object"!=typeof t||!t||"string"!=typeof r||!r||"function"!=typeof t[r])return(0,d.R)(29);const i=function(e){return(e||s.ee).get("logger")}(e),o=(0,R.YM)(i),a=new w.y(s.P);a.level=n.level,a.customAttributes=n.customAttributes;const c=t[r]?.[R.Jt]||t[r];return A.set(c,a),o.inPlace(t,[r],"wrap-logger-",(()=>A.get(c))),i}function _(){const e=(0,g.pV)();m.forEach((t=>{e[t]=(...r)=>function(t,...r){let n=[];return Object.values(e.initializedAgents).forEach((e=>{e&&e.api?e.exposed&&e.api[t]&&n.push(e.api[t](...r)):(0,d.R)(38,t)})),n.length>1?n:n[0]}(t,...r)}))}const x={};function N(e,t,g=!1){t||(0,c.Ak)(e,"api");const m={};var w=s.ee.get(e),R=w.get("tracer");x[e]=b.g.OFF,w.on(p.G4.REPLAY_RUNNING,(t=>{x[e]=t}));var A="api-",_=A+"ixn-";function N(t,r,n,o){const a=(0,i.Vp)(e);return null===r?delete a.jsAttributes[t]:(0,i.x1)(e,{...a,jsAttributes:{...a.jsAttributes,[t]:r}}),j(A,n,!0,o||null===r?"session":void 0)(t,r)}function k(){}m.log=function(e,{customAttributes:t={},level:r=y.p_.INFO}={}){(0,a.p)(f.xV,["API/log/called"],void 0,n.K7.metrics,w),function(e,t,r={},i=y.p_.INFO){(0,a.p)(f.xV,["API/logging/".concat(i.toLowerCase(),"/called")],void 0,n.K7.metrics,e),(0,a.p)(y.ET,[(0,v.t)(),t,r,i],void 0,n.K7.logging,e)}(w,e,t,r)},m.wrapLogger=(e,t,{customAttributes:r={},level:i=y.p_.INFO}={})=>{(0,a.p)(f.xV,["API/wrapLogger/called"],void 0,n.K7.metrics,w),E(w,e,t,{customAttributes:r,level:i})},h.forEach((e=>{m[e]=j(A,e,!0,"api")})),m.addPageAction=j(A,"addPageAction",!0,n.K7.genericEvents),m.recordCustomEvent=j(A,"recordCustomEvent",!0,n.K7.genericEvents),m.setPageViewName=function(t,r){if("string"==typeof t)return"/"!==t.charAt(0)&&(t="/"+t),(0,o.f)(e).customTransaction=(r||"http://custom.transaction")+t,j(A,"setPageViewName",!0)()},m.setCustomAttribute=function(e,t,r=!1){if("string"==typeof e){if(["string","number","boolean"].includes(typeof t)||null===t)return N(e,t,"setCustomAttribute",r);(0,d.R)(40,typeof t)}else(0,d.R)(39,typeof e)},m.setUserId=function(e){if("string"==typeof e||null===e)return N("enduser.id",e,"setUserId",!0);(0,d.R)(41,typeof e)},m.setApplicationVersion=function(e){if("string"==typeof e||null===e)return N("application.version",e,"setApplicationVersion",!1);(0,d.R)(42,typeof e)},m.start=()=>{try{(0,a.p)(f.xV,["API/start/called"],void 0,n.K7.metrics,w),w.emit("manual-start-all")}catch(e){(0,d.R)(23,e)}},m[p.G4.RECORD]=function(){(0,a.p)(f.xV,["API/recordReplay/called"],void 0,n.K7.metrics,w),(0,a.p)(p.G4.RECORD,[],void 0,n.K7.sessionReplay,w)},m[p.G4.PAUSE]=function(){(0,a.p)(f.xV,["API/pauseReplay/called"],void 0,n.K7.metrics,w),(0,a.p)(p.G4.PAUSE,[],void 0,n.K7.sessionReplay,w)},m.interaction=function(e){return(new k).get("object"==typeof e?e:{})};const T=k.prototype={createTracer:function(e,t){var r={},i=this,o="function"==typeof t;return(0,a.p)(f.xV,["API/createTracer/called"],void 0,n.K7.metrics,w),g||(0,a.p)(_+"tracer",[(0,v.t)(),e,r],i,n.K7.spa,w),function(){if(R.emit((o?"":"no-")+"fn-start",[(0,v.t)(),i,o],r),o)try{return t.apply(this,arguments)}catch(e){const t="string"==typeof e?new Error(e):e;throw R.emit("fn-err",[arguments,this,t],r),t}finally{R.emit("fn-end",[(0,v.t)()],r)}}}};function j(e,t,r,i){return function(){return(0,a.p)(f.xV,["API/"+t+"/called"],void 0,n.K7.metrics,w),i&&(0,a.p)(e+t,[r?(0,v.t)():performance.now(),...arguments],r?null:this,i,w),r?void 0:this}}function I(){r.e(296).then(r.bind(r,778)).then((({setAPI:t})=>{t(e),(0,c.Ze)(e,"api")})).catch((e=>{(0,d.R)(27,e),w.abort()}))}return["actionText","setName","setAttribute","save","ignore","onEnd","getContext","end","get"].forEach((e=>{T[e]=j(_,e,void 0,g?n.K7.softNav:n.K7.spa)})),m.setCurrentRouteName=g?j(_,"routeName",void 0,n.K7.softNav):j(A,"routeName",!0,n.K7.spa),m.noticeError=function(t,r){"string"==typeof t&&(t=new Error(t)),(0,a.p)(f.xV,["API/noticeError/called"],void 0,n.K7.metrics,w),(0,a.p)("err",[t,(0,v.t)(),!1,r,!!x[e]],void 0,n.K7.jserrors,w)},l.RI?(0,u.GG)((()=>I()),!0):I(),m}var k=r(217),T=r(122);const j={accountID:void 0,trustKey:void 0,agentID:void 0,licenseKey:void 0,applicationID:void 0,xpid:void 0},I={};var O=r(284);const S=e=>{const t=e.startsWith("http");e+="/",r.p=t?e:"https://"+e};let P=!1;function K(e,t={},r,n){let{init:a,info:c,loader_config:u,runtime:d={},exposed:f=!0}=t;d.loaderType=r;const p=(0,g.pV)();c||(a=p.init,c=p.info,u=p.loader_config),(0,k.xN)(e.agentIdentifier,a||{}),function(e,t){if(!e)throw new Error("All loader-config objects require an agent identifier!");I[e]=(0,T.a)(t,j);const r=(0,g.nY)(e);r&&(r.loader_config=I[e])}(e.agentIdentifier,u||{}),c.jsAttributes??={},l.bv&&(c.jsAttributes.isWorker=!0),(0,i.x1)(e.agentIdentifier,c);const m=(0,k.D0)(e.agentIdentifier),h=[c.beacon,c.errorBeacon];P||(m.proxy.assets&&(S(m.proxy.assets),h.push(m.proxy.assets)),m.proxy.beacon&&h.push(m.proxy.beacon),_(),(0,g.US)("activatedFeatures",O.B),e.runSoftNavOverSpa&&=!0===m.soft_navigations.enabled&&m.feature_flags.includes("soft_nav")),d.denyList=[...m.ajax.deny_list||[],...m.ajax.block_internal?h:[]],d.ptid=e.agentIdentifier,(0,o.V)(e.agentIdentifier,d),e.ee=s.ee.get(e.agentIdentifier),void 0===e.api&&(e.api=N(e.agentIdentifier,n,e.runSoftNavOverSpa)),void 0===e.exposed&&(e.exposed=f),P=!0}},374:(e,t,r)=>{r.nc=(()=>{try{return document?.currentScript?.nonce}catch(e){}return""})()},860:(e,t,r)=>{"use strict";r.d(t,{$J:()=>u,K7:()=>s,P3:()=>c,XX:()=>i,qY:()=>n,v4:()=>a});const n="events",i="jserrors",o="browser/blobs",a="rum",s={ajax:"ajax",genericEvents:"generic_events",jserrors:i,logging:"logging",metrics:"metrics",pageAction:"page_action",pageViewEvent:"page_view_event",pageViewTiming:"page_view_timing",sessionReplay:"session_replay",sessionTrace:"session_trace",softNav:"soft_navigations",spa:"spa"},c={[s.pageViewEvent]:1,[s.pageViewTiming]:2,[s.metrics]:3,[s.jserrors]:4,[s.spa]:5,[s.ajax]:6,[s.sessionTrace]:7,[s.softNav]:8,[s.sessionReplay]:9,[s.logging]:10,[s.genericEvents]:11},u={[s.pageViewEvent]:a,[s.pageViewTiming]:n,[s.ajax]:n,[s.spa]:n,[s.softNav]:n,[s.metrics]:i,[s.jserrors]:i,[s.sessionTrace]:o,[s.sessionReplay]:o,[s.logging]:"browser/logs",[s.genericEvents]:"ins"}}},n={};function i(e){var t=n[e];if(void 0!==t)return t.exports;var o=n[e]={exports:{}};return r[e](o,o.exports,i),o.exports}i.m=r,i.d=(e,t)=>{for(var r in t)i.o(t,r)&&!i.o(e,r)&&Object.defineProperty(e,r,{enumerable:!0,get:t[r]})},i.f={},i.e=e=>Promise.all(Object.keys(i.f).reduce(((t,r)=>(i.f[r](e,t),t)),[])),i.u=e=>"nr-rum-1.283.2.min.js",i.o=(e,t)=>Object.prototype.hasOwnProperty.call(e,t),e={},t="NRBA-1.283.2.PROD:",i.l=(r,n,o,a)=>{if(e[r])e[r].push(n);else{var s,c;if(void 0!==o)for(var u=document.getElementsByTagName("script"),l=0;l<u.length;l++){var d=u[l];if(d.getAttribute("src")==r||d.getAttribute("data-webpack")==t+o){s=d;break}}if(!s){c=!0;var f={296:"sha512-2Y8GMAOGF658KnXzOZ/v+DlLch8TBFvV0tTNnOy9wrpvtDa1t5CdZMyX+LubTymBlzPp6NUjllBghMCZqXBPmg=="};(s=document.createElement("script")).charset="utf-8",s.timeout=120,i.nc&&s.setAttribute("nonce",i.nc),s.setAttribute("data-webpack",t+o),s.src=r,0!==s.src.indexOf(window.location.origin+"/")&&(s.crossOrigin="anonymous"),f[a]&&(s.integrity=f[a])}e[r]=[n];var g=(t,n)=>{s.onerror=s.onload=null,clearTimeout(p);var i=e[r];if(delete e[r],s.parentNode&&s.parentNode.removeChild(s),i&&i.forEach((e=>e(n))),t)return t(n)},p=setTimeout(g.bind(null,void 0,{type:"timeout",target:s}),12e4);s.onerror=g.bind(null,s.onerror),s.onload=g.bind(null,s.onload),c&&document.head.appendChild(s)}},i.r=e=>{"undefined"!=typeof Symbol&&Symbol.toStringTag&&Object.defineProperty(e,Symbol.toStringTag,{value:"Module"}),Object.defineProperty(e,"__esModule",{value:!0})},i.p="https://js-agent.newrelic.com/",(()=>{var e={374:0,840:0};i.f.j=(t,r)=>{var n=i.o(e,t)?e[t]:void 0;if(0!==n)if(n)r.push(n[2]);else{var o=new Promise(((r,i)=>n=e[t]=[r,i]));r.push(n[2]=o);var a=i.p+i.u(t),s=new Error;i.l(a,(r=>{if(i.o(e,t)&&(0!==(n=e[t])&&(e[t]=void 0),n)){var o=r&&("load"===r.type?"missing":r.type),a=r&&r.target&&r.target.src;s.message="Loading chunk "+t+" failed.\n("+o+": "+a+")",s.name="ChunkLoadError",s.type=o,s.request=a,n[1](s)}}),"chunk-"+t,t)}};var t=(t,r)=>{var n,o,[a,s,c]=r,u=0;if(a.some((t=>0!==e[t]))){for(n in s)i.o(s,n)&&(i.m[n]=s[n]);if(c)c(i)}for(t&&t(r);u<a.length;u++)o=a[u],i.o(e,o)&&e[o]&&e[o][0](),e[o]=0},r=self["webpackChunk:NRBA-1.283.2.PROD"]=self["webpackChunk:NRBA-1.283.2.PROD"]||[];r.forEach(t.bind(null,0)),r.push=t.bind(null,r.push.bind(r))})(),(()=>{"use strict";i(374);var e=i(944),t=i(344),r=i(566);class n{agentIdentifier;constructor(){this.agentIdentifier=(0,r.LA)(16)}#e(t,...r){if("function"==typeof this.api?.[t])return this.api[t](...r);(0,e.R)(35,t)}addPageAction(e,t){return this.#e("addPageAction",e,t)}recordCustomEvent(e,t){return this.#e("recordCustomEvent",e,t)}setPageViewName(e,t){return this.#e("setPageViewName",e,t)}setCustomAttribute(e,t,r){return this.#e("setCustomAttribute",e,t,r)}noticeError(e,t){return this.#e("noticeError",e,t)}setUserId(e){return this.#e("setUserId",e)}setApplicationVersion(e){return this.#e("setApplicationVersion",e)}setErrorHandler(e){return this.#e("setErrorHandler",e)}addRelease(e,t){return this.#e("addRelease",e,t)}log(e,t){return this.#e("log",e,t)}}class o extends n{#e(t,...r){if("function"==typeof this.api?.[t])return this.api[t](...r);(0,e.R)(35,t)}start(){return this.#e("start")}finished(e){return this.#e("finished",e)}recordReplay(){return this.#e(t.G4.RECORD)}pauseReplay(){return this.#e(t.G4.PAUSE)}addToTrace(e){return this.#e("addToTrace",e)}setCurrentRouteName(e){return this.#e("setCurrentRouteName",e)}interaction(){return this.#e("interaction")}wrapLogger(e,t,r){return this.#e("wrapLogger",e,t,r)}}var a=i(860),s=i(217);const c=Object.values(a.K7);function u(e){const t={};return c.forEach((r=>{t[r]=function(e,t){return!0===(0,s.gD)(t,"".concat(e,".enabled"))}(r,e)})),t}var l=i(603);var d=i(687),f=i(234),g=i(289),p=i(154),m=i(384);const h=e=>p.RI&&!0===(0,s.gD)(e,"privacy.cookies_enabled");function v(e){return!!(0,m.dV)().o.MO&&h(e)&&!0===(0,s.gD)(e,"session_trace.enabled")}var b=i(389);class y extends f.W{constructor(e,t,r=!0){super(e.agentIdentifier,t),this.auto=r,this.abortHandler=void 0,this.featAggregate=void 0,this.onAggregateImported=void 0,!1===e.init[this.featureName].autoStart&&(this.auto=!1),this.auto?(0,d.Ak)(e.agentIdentifier,t):this.ee.on("manual-start-all",(0,b.J)((()=>{(0,d.Ak)(e.agentIdentifier,this.featureName),this.auto=!0,this.importAggregator(e)})))}importAggregator(t,r={}){if(this.featAggregate||!this.auto)return;let n;this.onAggregateImported=new Promise((e=>{n=e}));const o=async()=>{let o;try{if(h(this.agentIdentifier)){const{setupAgentSession:e}=await i.e(296).then(i.bind(i,861));o=e(t)}}catch(t){(0,e.R)(20,t),this.ee.emit("internal-error",[t]),this.featureName===a.K7.sessionReplay&&this.abortHandler?.()}try{if(!this.#t(this.featureName,o))return(0,d.Ze)(this.agentIdentifier,this.featureName),void n(!1);const{lazyFeatureLoader:e}=await i.e(296).then(i.bind(i,103)),{Aggregate:a}=await e(this.featureName,"aggregate");this.featAggregate=new a(t,r),t.runtime.harvester.initializedAggregates.push(this.featAggregate),n(!0)}catch(t){(0,e.R)(34,t),this.abortHandler?.(),(0,d.Ze)(this.agentIdentifier,this.featureName,!0),n(!1),this.ee&&this.ee.abort()}};p.RI?(0,g.GG)((()=>o()),!0):o()}#t(e,t){switch(e){case a.K7.sessionReplay:return v(this.agentIdentifier)&&!!t;case a.K7.sessionTrace:return!!t;default:return!0}}}var w=i(630);class R extends y{static featureName=w.T;constructor(e,t=!0){super(e,w.T,t),this.importAggregator(e)}}var A=i(908),E=i(843),_=i(878),x=i(782),N=i(863);class k extends y{static featureName=x.T;constructor(e,t=!0){super(e,x.T,t),p.RI&&((0,E.u)((()=>(0,A.p)("docHidden",[(0,N.t)()],void 0,x.T,this.ee)),!0),(0,_.sp)("pagehide",(()=>(0,A.p)("winPagehide",[(0,N.t)()],void 0,x.T,this.ee))),this.importAggregator(e))}}var T=i(773);class j extends y{static featureName=T.TZ;constructor(e,t=!0){super(e,T.TZ,t),this.importAggregator(e)}}new class extends o{constructor(t){super(),p.gm?(this.features={},(0,m.bQ)(this.agentIdentifier,this),this.desiredFeatures=new Set(t.features||[]),this.desiredFeatures.add(R),this.runSoftNavOverSpa=[...this.desiredFeatures].some((e=>e.featureName===a.K7.softNav)),(0,l.j)(this,t,t.loaderType||"agent"),this.run()):(0,e.R)(21)}get config(){return{info:this.info,init:this.init,loader_config:this.loader_config,runtime:this.runtime}}run(){try{const t=u(this.agentIdentifier),r=[...this.desiredFeatures];r.sort(((e,t)=>a.P3[e.featureName]-a.P3[t.featureName])),r.forEach((r=>{if(!t[r.featureName]&&r.featureName!==a.K7.pageViewEvent)return;if(this.runSoftNavOverSpa&&r.featureName===a.K7.spa)return;if(!this.runSoftNavOverSpa&&r.featureName===a.K7.softNav)return;const n=function(e){switch(e){case a.K7.ajax:return[a.K7.jserrors];case a.K7.sessionTrace:return[a.K7.ajax,a.K7.pageViewEvent];case a.K7.sessionReplay:return[a.K7.sessionTrace];case a.K7.pageViewTiming:return[a.K7.pageViewEvent];default:return[]}}(r.featureName).filter((e=>!(e in this.features)));n.length>0&&(0,e.R)(36,{targetFeature:r.featureName,missingDependencies:n}),this.features[r.featureName]=new r(this)}))}catch(t){(0,e.R)(22,t);for(const e in this.features)this.features[e].abortHandler?.();const r=(0,m.Zm)();delete r.initializedAgents[this.agentIdentifier]?.api,delete r.initializedAgents[this.agentIdentifier]?.features,delete this.sharedAggregator;return r.ee.get(this.agentIdentifier).abort(),!1}}}({features:[R,k,j],loaderType:"lite"})})()})();</script>
<noscript><style>form.antibot * :not(.antibot-message) { display: none !important; }</style>
</noscript><script async src="https://www.googletagmanager.com/gtag/js?id=G-HEQ0YF2VYL"></script>
<script>window.dataLayer = window.dataLayer || [];function gtag(){dataLayer.push(arguments)};gtag("js", new Date());gtag("set", "developer_id.dMDhkMT", true);gtag('set', {'cookie_flags': 'SameSite=None;Secure', 'cookie_domain': 'www.nist.gov'});gtag("config", "G-HEQ0YF2VYL", {"groups":"default","page_placeholder":"PLACEHOLDER_page_location","link_attribution":true,"allow_ad_personalization_signals":false});gtag("config", "G-CSLL4ZEK4L", {"groups":"default","page_placeholder":"PLACEHOLDER_page_location","link_attribution":true,"allow_ad_personalization_signals":false});gtag("event", "custom", {"node_title":"How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero ","node_id":"1847761","blog_author":"Stephen Eckel ","content_type":"Blog entry"});</script>
<meta name="description" content="On Lord Kelvin’s 200th birthday today, we’re remembering the scientist who brought us the metric (SI) unit for temperature" />
<link rel="canonical" href="https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero" />
<link rel="shortlink" href="https://www.nist.gov/node/1847761" />
<meta name="citation_title" content="How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero | NIST" />
<meta property="og:site_name" content="NIST" />
<meta property="og:type" content="Article" />
<meta property="og:url" content="https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero" />
<meta property="og:title" content="How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero" />
<meta property="og:description" content="On Lord Kelvin’s 200th birthday today, we’re remembering the scientist who brought us the metric (SI) unit for temperature" />
<meta property="og:image" content="https://www.nist.gov/sites/default/files/styles/social/public/images/2024/05/07/Steve_lCAVS.jpg?itok=So7P5SsA" />
<meta property="og:image" content="https://www.nist.gov/themes/custom/nist_www/img/homepage/nist_mark.png" />
<meta property="og:image:width" content="2400" />
<meta property="og:image:height" content="1704" />
<meta property="og:image:alt" content="Stephen Eckel wears dark safety glasses as he peers into the complex CAVS apparatus in a darkened lab." />
<meta property="article:author" content="Stephen Eckel" />
<meta property="article:published_time" content="2024-06-26T08:00-04:00" />
<meta property="article:modified_time" content="2025-01-30T07:27-05:00" />
<meta name="dcterms.title" content="How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero" />
<meta name="dcterms.creator" content="Stephen Eckel" />
<meta name="dcterms.description" content="On Lord Kelvin’s 200th birthday today, we’re remembering the scientist who brought us the metric (SI) unit for temperature" />
<meta name="dcterms.publisher" content="Stephen Eckel" />
<meta name="dcterms.contributor" content="NIST" />
<meta name="dcterms.date" content="2024-06-26T08:00-04:00" />
<meta name="dcterms.type" content="text" />
<meta name="dcterms.format" content="text/html" />
<meta name="dcterms.identifier" content="https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero" />
<meta name="dcterms.source" content="NIST" />
<meta name="dcterms.created" content="2024-06-26T08:00-04:00" />
<meta name="dcterms.modified" content="2025-01-30T07:27-05:00" />
<meta name="twitter:card" content="summary_large_image" />
<meta name="twitter:description" content="On Lord Kelvin’s 200th birthday today, we’re remembering the scientist who brought us the metric (SI) unit for temperature" />
<meta name="twitter:site" content="NIST" />
<meta name="twitter:title" content="How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero" />
<meta name="google-site-verification" content="QMu0ODkER3rN5hLcMLqNVf7e3bkjYsNLTuhqfH48jCA" />
<meta name="Generator" content="Drupal 10 (https://www.drupal.org)" />
<meta name="MobileOptimized" content="width" />
<meta name="HandheldFriendly" content="true" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="nist_search_modified" class="elastic" content="2025-01-30T07:27:00-05:00" />
<script type="application/ld+json">{
"@context": "https://schema.org",
"@graph": [
{
"@type": "Article",
"@id": "https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero",
"headline": "How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero",
"name": "How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero",
"description": "On Lord Kelvin’s 200th birthday today, we’re remembering the scientist who brought us the metric (SI) unit for temperature.",
"image": {
"@type": "ImageObject",
"url": "https://www.nist.gov/sites/default/files/styles/social/public/images/2024/05/07/Steve_lCAVS.jpg?itok=So7P5SsA",
"width": "2400",
"height": "1704"
},
"datePublished": "2024-06-26T08:00-04:00",
"dateModified": "2025-01-30T07:27-05:00",
"author": {
"@type": "Person",
"@id": "https://www.nist.gov/blogs/taking-measure/authors/stephen-eckel",
"name": "Stephen Eckel",
"url": "https://www.nist.gov/blogs/taking-measure/authors/stephen-eckel"
},
"publisher": {
"@type": "GovernmentOrganization",
"@id": "https://www.nist.gov/",
"name": "National Institute of Standards and Technology",
"url": "https://www.nist.gov/"
}
}
]
}</script>
<meta name="nist_search_bundle" class="elastic" content="blog" />
<link rel="icon" href="/themes/custom/nist_www/favicon.ico" type="image/vnd.microsoft.icon" />
<title>How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero | NIST</title>
<link rel="stylesheet" media="all" href="/sites/default/files/css/css_ATE3iYhXfs_l1UNAQ5dNrjlIpqRdj3PF4iwua2gUjME.css?delta=0&amp;language=en&amp;theme=nist_www&amp;include=eJxFjoEOgyAMRH-IyCeRAtU1Fmpolfn3w7nFpGl6zbvcRUhrMBmz-fjcgZJUV0kt2AsLjp9whBaKZJ9JITIGpro6PdWwDK_il_cLSwS-vb33v8a3XbzPbd-Ap5-8LQWWSjMlNxMbNp9gMxr5KomAQ8FMcCUMguGU3cKokOTAdnqpmITdQdjVf_c0Ou6MT4NCqYmS4QdZJF1F" />
<link rel="stylesheet" media="all" href="/sites/default/files/css/css_kGS0ApDpFo-_3JI4Ijxg4RCWlTqsImK3lqH7bCv5v2U.css?delta=1&amp;language=en&amp;theme=nist_www&amp;include=eJxFjoEOgyAMRH-IyCeRAtU1Fmpolfn3w7nFpGl6zbvcRUhrMBmz-fjcgZJUV0kt2AsLjp9whBaKZJ9JITIGpro6PdWwDK_il_cLSwS-vb33v8a3XbzPbd-Ap5-8LQWWSjMlNxMbNp9gMxr5KomAQ8FMcCUMguGU3cKokOTAdnqpmITdQdjVf_c0Ou6MT4NCqYmS4QdZJF1F" />
<link rel="stylesheet" media="print" href="/sites/default/files/css/css_-IXwLuTUdm8IGHxib8GX8wWKw3LjKsNWSYYskZ5fEGg.css?delta=2&amp;language=en&amp;theme=nist_www&amp;include=eJxFjoEOgyAMRH-IyCeRAtU1Fmpolfn3w7nFpGl6zbvcRUhrMBmz-fjcgZJUV0kt2AsLjp9whBaKZJ9JITIGpro6PdWwDK_il_cLSwS-vb33v8a3XbzPbd-Ap5-8LQWWSjMlNxMbNp9gMxr5KomAQ8FMcCUMguGU3cKokOTAdnqpmITdQdjVf_c0Ou6MT4NCqYmS4QdZJF1F" />
<link rel="stylesheet" media="all" href="/sites/default/files/css/css_RS8YGnRq2Xi5aD-GQC3GKwBe6bOWBBmEmXrb2xB5FMM.css?delta=3&amp;language=en&amp;theme=nist_www&amp;include=eJxFjoEOgyAMRH-IyCeRAtU1Fmpolfn3w7nFpGl6zbvcRUhrMBmz-fjcgZJUV0kt2AsLjp9whBaKZJ9JITIGpro6PdWwDK_il_cLSwS-vb33v8a3XbzPbd-Ap5-8LQWWSjMlNxMbNp9gMxr5KomAQ8FMcCUMguGU3cKokOTAdnqpmITdQdjVf_c0Ou6MT4NCqYmS4QdZJF1F" />
<script src="/sites/default/files/js/js_GM8kl6wk698qKTTwusj83bCoGHHtOZ1UinjY1sE_Qbk.js?scope=header&amp;delta=0&amp;language=en&amp;theme=nist_www&amp;include=eJxdjdEOwiAMRX9o2E9qyqhYBboAE_17YW7RLOGBc3p7a2l-YNX-FrC_P97L5FV9YKRE4V1lLnAWU5JS8SrdOW0pKDmsuZdI8uDpOy5SWeKS9clwFuPK5uqNI_e7GixljOrASSHbi4Okx5YBH9RSMPsK3Jgc5wOxtfaX4Fcdi-DyulC47DjNGiOneugdjX2bp3Dj_G2O5JNcZZ6GLHhf44I9t8LGZrAZ_AFBzXxL"></script>
</head>
<body class="node-1847761">
<a href="#main-content" class="visually-hidden focusable" data-elastic-exclude>
Skip to main content
</a>
<div class="dialog-off-canvas-main-canvas" data-off-canvas-main-canvas>
<!-- nist-index-ignore-start -->
<section data-elastic-exclude class="usa-banner" aria-label="Official government website">
<div class="usa-accordion">
<header class="usa-banner__header">
<div class="usa-banner__inner">
<div class="grid-col-auto">
<img class="usa-banner__header-flag" src="/libraries/nist-component-library/dist/img/us_flag_small.png" alt="U.S. flag">
</div>
<div class="grid-col-fill tablet:grid-col-auto">
<p class="usa-banner__header-text">An official website of the United States government</p>
<p class="usa-banner__header-action" aria-hidden="true">Here’s how you know</p>
</div>
<button class="usa-accordion__button usa-banner__button" aria-expanded="false" aria-controls="gov-banner-default">
<span class="usa-banner__button-text">Here’s how you know</span>
</button>
</div>
</header>
<div class="usa-banner__content usa-accordion__content" id="gov-banner-default">
<div class="grid-row grid-gap-lg">
<div class="usa-banner__guidance tablet:grid-col-6">
<img class="usa-banner__icon usa-media-block__img" src="/libraries/nist-component-library/dist/img/icon-dot-gov.svg" role="img" alt="" aria-hidden="true">
<div class="usa-media-block__body">
<p>
<strong>Official websites use .gov</strong>
<br/>
A <strong>.gov</strong> website belongs to an official government organization in the United States.
</p>
</div>
</div>
<div class="usa-banner__guidance tablet:grid-col-6">
<img class="usa-banner__icon usa-media-block__img" src="/libraries/nist-component-library/dist/img/icon-https.svg" role="img" alt="" aria-hidden="true">
<div class="usa-media-block__body">
<p>
<strong>Secure .gov websites use HTTPS</strong>
<br/>
A <strong>lock</strong> ( <span class="icon-lock">
<svg xmlns="http://www.w3.org/2000/svg" width="52" height="64" viewbox="0 0 52 64" class="usa-banner__lock-image" role="img" aria-labelledby="banner-lock-title banner-lock-description" focusable="false">
<title id="banner-lock-title">Lock</title>
<desc id="banner-lock-description">A locked padlock</desc><path fill="#000000" fill-rule="evenodd" d="M26 0c10.493 0 19 8.507 19 19v9h3a4 4 0 0 1 4 4v28a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4V32a4 4 0 0 1 4-4h3v-9C7 8.507 15.507 0 26 0zm0 8c-5.979 0-10.843 4.77-10.996 10.712L15 19v9h22v-9c0-6.075-4.925-11-11-11z"/></svg>
</span>
) or <strong>https://</strong> means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
</p>
</div>
</div>
</div>
</div>
</div>
</section>
<!-- nist-index-ignore-end -->
<div data-elastic-exclude>
<!-- nist-index-ignore-start -->
<div class="nist-print-header" style="display:none;">
<p class="nist-print-header__url">https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero</p>
<img class="nist-print-header__logo" width="289" height="38" src="/libraries/nist-component-library/dist/img/logo/nist_logo_sidestack.svg" alt="National Institute of Standards and Technology" />
</div>
<div class="usa-overlay"></div>
<header class="usa-header nist-header--www nist-header--minimal" role="banner">
<div class="usa-navbar">
<div class="usa-logo flex-fill">
<a href="/" title="National Institute of Standards and Technology" aria-label="Home">
<img src="/libraries/nist-component-library/dist/img/logo/logo.svg" alt="National Institute of Standards and Technology" width="300px" height="80px" />
</a>
</div>
<div class="usa-header__right grid-row flex-auto">
<div class="grid-col-fill nist-header__search-group">
<form class="usa-search usa-search--small"
accept-charset="UTF-8"
action="/search"
id="search_form"
method="get">
<div role="search">
<label class="usa-sr-only" for="search-form">Search NIST</label>
<input class="usa-input" id="search-form" type="search" name="s" placeholder="Search NIST" required="" maxlength="128">
<button class="usa-button" type="submit"><img src="/libraries/nist-component-library/dist/img/usa-icons-bg/search--white.svg" class="usa-search__submit-icon" alt="Search"></button>
</div>
</form>
</div>
<div class="grid-col-auto padding-left-1">
<button class="usa-menu-btn">Menu</button>
</div>
</div>
</div>
<nav aria-label="Primary navigation" class="usa-nav">
<div class="usa-nav__inner">
<button class="usa-nav__close">Close</button>
<ul class="usa-nav__primary usa-accordion">
<li class="usa-nav__primary-item">
<a class="usa-nav__link" href="/publications">Publications</a>
</li>
<li class="usa-nav__primary-item">
<button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-2"><span>What We Do</span></button>
<div id="primary_menu-2" class="usa-nav__submenu usa-megamenu">
<div class="grid-row">
<div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/topics" class="usa-nav__link">All Topics</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/advanced-communications" class="usa-nav__link">Advanced communications</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/artificial-intelligence" class="usa-nav__link">Artificial intelligence</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/bioscience" class="usa-nav__link">Bioscience</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/buildings-construction" class="usa-nav__link">Buildings and construction</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/chemistry" class="usa-nav__link">Chemistry</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/cybersecurity" class="usa-nav__link">Cybersecurity</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/electronics" class="usa-nav__link">Electronics</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/energy" class="usa-nav__link">Energy</a>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/environment" class="usa-nav__link">Environment</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/fire" class="usa-nav__link">Fire</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/forensic-science" class="usa-nav__link">Forensic science</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/health" class="usa-nav__link">Health</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/information-technology" class="usa-nav__link">Information technology</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/infrastructure" class="usa-nav__link">Infrastructure</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/manufacturing" class="usa-nav__link">Manufacturing</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/materials" class="usa-nav__link">Materials</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/mathematics-statistics" class="usa-nav__link">Mathematics and statistics</a>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/metrology" class="usa-nav__link">Metrology</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/nanotechnology" class="usa-nav__link">Nanotechnology</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/neutron-research" class="usa-nav__link">Neutron research</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/performance-excellence" class="usa-nav__link">Performance excellence</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/physics" class="usa-nav__link">Physics</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/public-safety" class="usa-nav__link">Public safety</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/quantum-information-science" class="usa-nav__link">Quantum information science</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/resilience" class="usa-nav__link">Resilience</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/standards" class="usa-nav__link">Standards</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/transportation" class="usa-nav__link">Transportation</a>
</li>
</ul>
</div>
</div>
</div>
</li>
<li class="usa-nav__primary-item">
<button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-3"><span>Labs &amp; Major Programs</span></button>
<div id="primary_menu-3" class="usa-nav__submenu usa-megamenu">
<div class="grid-row">
<div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/adlp" class="usa-nav__link">Assoc Director of Laboratory Programs</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/laboratories" class="usa-nav__link">Laboratories</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="/ctl" class="usa-nav__link">Communications Technology Laboratory</a>
</li>
<li>
<a href="/el" class="usa-nav__link">Engineering Laboratory</a>
</li>
<li>
<a href="/itl" class="usa-nav__link">Information Technology Laboratory</a>
</li>
<li>
<a href="/mml" class="usa-nav__link">Material Measurement Laboratory</a>
</li>
<li>
<a href="/pml" class="usa-nav__link">Physical Measurement Laboratory</a>
</li>
</ul>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/user-facilities" class="usa-nav__link">User Facilities</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="/ncnr" class="usa-nav__link">NIST Center for Neutron Research</a>
</li>
<li>
<a href="/cnst" class="usa-nav__link">CNST NanoFab</a>
</li>
</ul>
</li>
<li class="usa-nav__submenu-item">
<a href="/labs-major-programs/research-test-beds" class="usa-nav__link">Research Test Beds</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/laboratories/projects-programs" class="usa-nav__link">Research Projects</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/laboratories/tools-instruments" class="usa-nav__link">Tools &amp; Instruments</a>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/major-programs" class="usa-nav__link">Major Programs</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="/baldrige" class="usa-nav__link">Baldrige Performance Excellence Program</a>
</li>
<li>
<a href="/chips" class="usa-nav__link">CHIPS for America Initiative</a>
</li>
<li>
<a href="/mep" class="usa-nav__link">Manufacturing Extension Partnership (MEP)</a>
</li>
<li>
<a href="/oam" class="usa-nav__link">Office of Advanced Manufacturing</a>
</li>
<li>
<a href="/spo" class="usa-nav__link">Special Programs Office</a>
</li>
<li>
<a href="/tpo" class="usa-nav__link">Technology Partnerships Office</a>
</li>
</ul>
</li>
</ul>
</div>
</div>
</div>
</li>
<li class="usa-nav__primary-item">
<button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-4"><span>Services &amp; Resources</span></button>
<div id="primary_menu-4" class="usa-nav__submenu usa-megamenu">
<div class="grid-row">
<div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/content/standards-measurements" class="usa-nav__link">Standards and Measurements</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="/calibrations" class="usa-nav__link">Calibration Services</a>
</li>
<li>
<a href="/nvlap" class="usa-nav__link">Laboratory Accreditation (NVLAP)</a>
</li>
<li>
<a href="/nist-quality-system" class="usa-nav__link">Quality System</a>
</li>
<li>
<a href="/srm" class="usa-nav__link">Standard Reference Materials (SRMs)</a>
</li>
<li>
<a href="/sri" class="usa-nav__link">Standard Reference Instruments (SRIs)</a>
</li>
<li>
<a href="/standardsgov" class="usa-nav__link">Standards.gov</a>
</li>
<li>
<a href="/pml/time-and-frequency-division/time-services" class="usa-nav__link">Time Services</a>
</li>
<li>
<a href="/pml/owm" class="usa-nav__link">Office of Weights and Measures</a>
</li>
</ul>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/services-resources/software" class="usa-nav__link">Software</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/data" class="usa-nav__link">Data</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="https://webbook.nist.gov/chemistry/" class="usa-nav__link">Chemistry WebBook</a>
</li>
<li>
<a href="https://nvd.nist.gov/" class="usa-nav__link">National Vulnerability Database</a>
</li>
<li>
<a href="/pml/productsservices/physical-reference-data" class="usa-nav__link">Physical Reference Data</a>
</li>
<li>
<a href="/srd" class="usa-nav__link">Standard Reference Data (SRD)</a>
</li>
</ul>
</li>
<li class="usa-nav__submenu-item">
<a href="https://shop.nist.gov/" class="usa-nav__link">Storefront</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/tpo" class="usa-nav__link">License &amp; Patents</a>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="https://csrc.nist.gov/" class="usa-nav__link">Computer Security Resource Center (CSRC)</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/nist-research-library" class="usa-nav__link">NIST Research Library</a>
</li>
</ul>
</div>
</div>
</div>
</li>
<li class="usa-nav__primary-item">
<button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-5"><span>News &amp; Events</span></button>
<div id="primary_menu-5" class="usa-nav__submenu usa-megamenu">
<div class="grid-row">
<div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/news-events/news" class="usa-nav__link">News</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/news-events/events" class="usa-nav__link">Events</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/blogs" class="usa-nav__link">Blogs</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/feature-stories" class="usa-nav__link">Feature Stories</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/awards" class="usa-nav__link">Awards</a>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/video-gallery" class="usa-nav__link">Video Gallery</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/image-gallery" class="usa-nav__link">Image Gallery</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/pao/media-contacts" class="usa-nav__link">Media Contacts</a>
</li>
</ul>
</div>
</div>
</div>
</li>
<li class="usa-nav__primary-item">
<button class="usa-accordion__button usa-nav__link" aria-expanded="false" aria-controls="primary_menu-6"><span>About NIST</span></button>
<div id="primary_menu-6" class="usa-nav__submenu usa-megamenu">
<div class="grid-row">
<div class="tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/about-nist" class="usa-nav__link">About Us</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="/director/leadership" class="usa-nav__link">Leadership</a>
</li>
<li>
<a href="/director/nist-organization-structure" class="usa-nav__link">Organization Structure</a>
</li>
<li>
<a href="/about-nist/budget-planning" class="usa-nav__link">Budget &amp; Planning</a>
</li>
</ul>
</li>
<li class="usa-nav__submenu-item">
<a href="/about-nist/contact-us" class="usa-nav__link">Contact Us</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/about-nist/visit" class="usa-nav__link">Visit</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/careers" class="usa-nav__link">Careers</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="/iaao/academic-affairs-office" class="usa-nav__link">Student programs</a>
</li>
</ul>
</li>
</ul></div><div class="column-break tablet:grid-col-fill"><ul class="usa-nav__submenu-list">
<li class="usa-nav__submenu-item">
<a href="/about-nist/work-nist" class="usa-nav__link">Work with NIST</a>
</li>
<li class="usa-nav__submenu-item">
<a href="/history" class="usa-nav__link">History</a>
<ul class="usa-nav__submenu-list">
<li>
<a href="http://nistdigitalarchives.contentdm.oclc.org/" class="usa-nav__link">NIST Digital Archives</a>
</li>
<li>
<a href="/nist-museum" class="usa-nav__link">NIST Museum</a>
</li>
<li>
<a href="/nist-and-nobel" class="usa-nav__link">NIST and the Nobel</a>
</li>
</ul>
</li>
<li class="usa-nav__submenu-item">
<a href="/education" class="usa-nav__link">Educational Resources</a>
</li>
</ul>
</div>
</div>
</div>
</li>
</ul>
</div>
</nav>
</header>
<!-- nist-index-ignore-end -->
</div>
<div class="grid-container">
</div>
<div
id="block-nist-www-content" class="nist-block"
>
<section
class="nist-page__content usa-section clearfix"
>
<a id="main-content" tabindex="-1"></a>
<div
class="nist-page__region nist-page__region--content-top-full"
>
<div
class="nist-block"
>
<div class="entity-reference">
<div class="nist-blog-header nist-blog-header--purple nist-blog-header--inner">
<div class="nist-blog-header__bkgrd">
<div class="nist-blog-header__main grid-container">
<div class="grid-row">
<h2 class="nist-blog-header__title">
<a href="/blogs/taking-measure"> Taking Measure
</a>
</h2>
<div class="nist-blog-header__tagline">
<p class="text">Just a Standard Blog</p>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="grid-container margin-top-4">
<div
class="nist-page__region nist-page__region--content-top"
>
<div
class="nist-block"
>
<h1 class="nist-page__title">How Low Can Temperature Go? Lord Kelvin and the Science of Absolute Zero</h1>
</div>
<div
class="font-body-md"
>
<div class="daterange"><time datetime="2024-06-26T12:00:00Z">June 26, 2024</time>
</div>
</div>
<div
class="nist-block"
>
<span>By: </span>
<a href="/blogs/taking-measure/authors/stephen-eckel" hreflang="en">Stephen Eckel</a>
</div>
<div
class="nist-block"
>
<!-- nist-index-ignore-start -->
<div data-elastic-exclude class="nist-block nist-social__wrapper">
<h2 class="nist-social__title">Share</h2>
<div class="social-media-sharing">
<div class="nist-social__wrapper--share">
<div>
<a target="_blank" rel="noopener" href="https://www.facebook.com/share.php?u=https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero"
title="Facebook" class="nist-social nist-social--facebook-gray">
<span>Facebook</span>
</a>
</div>
<div>
<a target="_blank" rel="noopener" href="https://www.linkedin.com/shareArticle?mini=true&amp;url=https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero&amp;source=https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero"
title="Linkedin" class="nist-social nist-social--linkedin-gray">
<span>Linkedin</span>
</a>
</div>
<div>
<a target="_blank" rel="noopener" href="https://x.com/intent/tweet?url=https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero&amp;status=https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero"
title="X.com" class="nist-social nist-social--x-gray">
<span>X.com</span>
</a>
</div>
<div>
<a href="mailto:?subject=NIST.gov&amp;body=Check out this site https://www.nist.gov/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero"
title="Email" class="nist-social nist-social--envelope-gray">
<span>Email</span>
</a>
</div>
</div>
</div>
</div>
<!-- nist-index-ignore-end -->
</div>
</div>
</div>
<div class="grid-container margin-top-4">
<div class="grid-row grid-gap-6">
<div
class="nist-page__region nist-page__region--content tablet-lg:grid-col-8"
>
<div
class="nist-block"
>
<div class="text-with-summary">
<figure class="nist-image--lightbox nist-image" data-lightbox="https://www.nist.gov/sites/default/files/styles/2800_x_2800_limit/public/images/2024/05/07/Steve_lCAVS.jpg?itok=1qoGbJ9Y" data-media-id="707716">
<img loading="lazy" src="/sites/default/files/styles/960_x_960_limit/public/images/2024/05/07/Steve_lCAVS.jpg?itok=-mUtIvwB" width="960" height="682" alt="Stephen Eckel wears dark safety glasses as he peers into the complex CAVS apparatus in a darkened lab. " typeof="foaf:Image" />
<figcaption class="nist-image__caption">
<div data-caption-editable="true" class="nist-image__caption-content">
<p>In Stephen Eckel’s lab at NIST, he gets to work with some of the coldest stuff in the universe.</p>
</div>
<div class="nist-image__credit">
<span class="nist-image__credit-label">Credit:</span>
NIST
</div>
</figcaption>
</figure>
<p class="MsoNormal">Temperature is probably the second most measured physical quantity in our modern world — after time.&nbsp;</p><p class="MsoNormal">When I wake up in the morning, the first thing I usually check is the time (to see if I should go back to sleep), but the second thing I check is the temperature outside (so that I know how to dress).&nbsp;</p><p class="MsoNormal">Temperature is such a common measurement that we sometimes forget how important it is. From dairy farming to rocketry, from climate science to weather prediction, so many things require an accurate knowledge of temperature.</p><p class="MsoNormal">The metric (SI) unit for temperature is called the kelvin, after <a href="https://digital.nls.uk/scientists/biographies/lord-kelvin/">Lord Kelvin</a>, whose 200th birthday we celebrate today.&nbsp;</p><h2>Lord Kelvin and the Early Science of Temperature&nbsp;</h2><p class="MsoNormal">Lord Kelvin, or William Thomson, worked in what was then the emerging field of thermodynamics — transforming heat into dynamical motion. He did this both as a student at the University of Cambridge and as a young professor at the University of Glasgow. Together with his close collaborator, James Joule, he researched all sorts of problems in <a href="https://www.gla.ac.uk/myglasgow/library/files/special/exhibns/Kelvin/joule.html">thermodynamics</a>, including temperature scales.</p><p class="MsoNormal">At the time, the scientifically accepted scale for temperature was the Celsius scale, with zero temperature being the freezing point of water and 100 degrees being the boiling point of water. But after studying how gases changed volume and pressure in response to changing temperature, Thomson, Joule and other scientists realized that there was an <a href="https://www.britannica.com/science/absolute-zero">absolute coldest temperature</a> that could be reached.</p> <figure class=" align-right nist-image" role="group">
<div>
<img alt="Illustrated portrait of Lord Kelvin from Scottish bank note." height="480" loading="lazy" src="/sites/default/files/styles/480_x_480_limit/public/images/2024/05/07/shutterstock_1951823371.jpg?itok=D0HnbtpQ" typeof="foaf:Image" width="469">
</div>
<figcaption class="nist-image__caption">On his 200th birthday today, we remember Lord Kelvin’s many contributions to science, including calculating the coldest possible temperature — known as absolute zero.<div class="nist-image__credit">
<span class="nist-image__credit-label">Credit:</span>
Prachaya Roekdeethaweesab/Shutterstock
</div></figcaption>
</figure>
<p class="MsoNormal">To understand how they reached this conclusion, consider a gas in a balloon. If you cooled the balloon, the gas inside would exert less pressure against the balloon itself and against the atmosphere outside it, causing the balloon’s volume to shrink.&nbsp;</p><p class="MsoNormal">Don’t believe me? Inflate a balloon and stick it in your freezer. When you pull it out, you can feel the balloon expand. Now extrapolate: How cold would you have to make the balloon to make its volume go to zero (ignoring the fact that the gas inside will eventually condense into a liquid)? That must be the coldest possible temperature because the balloon cannot have a negative volume.</p><p class="MsoNormal">In 1848, Lord Kelvin used similar reasoning to accurately calculate the absolute coldest temperature as negative 273.15 Celsius (or negative 459.67 degrees Fahrenheit). It would be roughly another decade before scientists like Lord Kelvin and Ludwig Boltzmann understood that at absolute zero, the <a href="https://digital.nls.uk/scientists/biographies/lord-kelvin/discoveries.html">molecules in the gas stop moving</a>.&nbsp;</p><p class="MsoNormal">Since 2019, all three of these scientists have been immortalized in the SI. The kelvin is our SI unit of temperature, defined through the <a href="/si-redefinition/kelvin-boltzmann-constant" data-entity-type="node" data-entity-uuid="4a221c84-0d7c-474c-b813-efa2e7000d2e" data-entity-substitution="canonical" title="Kelvin: Boltzmann Constant">Boltzmann constant</a>, which relates temperature to energy, the SI unit of which is the joule.</p><p class="MsoNormal">Today, atomic physicists like myself use a technique partly pioneered at NIST called <a href="/video/nist-unscripted-bill-phillips" data-entity-type="media" data-entity-uuid="f8f06c76-e87c-4b81-b283-698f37e028ad" data-entity-substitution="canonical" title="NIST Unscripted - Bill Phillips">laser cooling</a>, which uses lasers to cool clouds of between 100,000 and 1 billion atoms to temperatures of about 100 microkelvin. This temperature is 1/10,000th of a degree Celsius above absolute zero.&nbsp;</p><p class="MsoNormal">And we measure these ultracold temperatures in a way that would not be surprising to Lord Kelvin (although making such cold gases might be!).&nbsp;</p><p class="MsoNormal">We measure the average speed of the atoms in the gas. Researchers at NIST use such laser-cooled atoms for all sorts of applications, from atomic clocks to vacuum standards.</p><h2>Vacuum Standard</h2><p class="MsoNormal">Laser cooling atoms to near absolute zero only works inside a chamber where almost all the air has been removed by a pump to isolate the atoms from the surrounding environment. Such vacuum chambers are common and are used in industries such as semiconductor manufacturing.&nbsp;</p><p class="MsoNormal">Most of the components in your cellphone have been in and out of at least one vacuum chamber. The core components, like the central processing unit, have probably been through a chamber that has produced some of the best vacuums on Earth. For every trillion gas molecules that started in the chamber, all were removed but one. Such exquisite vacuums are required because leftover gas molecules can both contaminate the chip and scatter the ultraviolet light that is used to imprint the designed circuit. This can cause the chip to be ruined.</p><p class="MsoNormal">Amazingly, the current best way to measure such pure vacuums is by using what is effectively a vacuum tube. But now, the laser-cooled atoms in my lab may be the best sensor of ultralow vacuum pressures on Earth.&nbsp;</p><p class="MsoNormal">After the sensor atoms are cooled to near absolute zero, we hold the sensor atoms in a “trap” that is made entirely of magnetic fields. This trap is very weak, only able to hold onto the ultracold sensor atoms. The vacuum sensor works because if a cold sensor atom is struck by a leftover gas molecule, it will almost always be ejected from the weak trap. The rate at which this process occurs depends on the number of gas molecules the pump has left behind. Thus, determining the number of leftover gas molecules just involves counting the number of sensor atoms that remain after some time.&nbsp;</p><p class="MsoNormal">This “<a href="/news-events/news/2023/08/nist-demonstrates-new-primary-standard-measuring-ultralow-pressures" data-entity-type="node" data-entity-uuid="fcc68c5a-a188-42d0-ae8b-21ace5c5131e" data-entity-substitution="canonical" title="NIST Demonstrates a New ‘Primary Standard’ for Measuring Ultralow Pressures">cold-atom<span> vacuum standard (CAVS)</span></a>” is a new way of measuring vacuum pressure, which NIST has played a crucial role in developing. We anticipate it being used to measure ultrapure vacuums in semiconductor manufacturing, quantum computers and other big science experiments, such as an experiment detecting collisions of extremely distant black holes, known as the Laser Interferometer Gravitational Wave Observatory (LIGO).</p><p class="MsoNormal">Having a standard like the CAVS that always gives the correct vacuum pressure reading will help these applications build better vacuum chambers, diagnose problems and increase both reliability and productivity.</p><p class="MsoNormal">The CAVS is the only experiment that I am aware of that needs to measure two very different temperatures at the same time: the sensor atom temperature of around 100 microkelvin (very cold!) and the temperature of the leftover gas in the vacuum chamber, near room temperature at 300 kelvin.&nbsp;</p><p class="MsoNormal">I think Lord Kelvin would be amazed to learn that two very different temperatures could exist at the same time, and both need to be measured for a single experiment to work.</p>
<figure class=" align-center nist-image--lightbox nist-image" role="group">
<div data-lightbox="https://www.nist.gov/sites/default/files/styles/2800_x_2800_limit/public/images/2024/05/07/lord_kelvin_with_a_traffic_cone.jpeg?itok=VzcEDYwQ" data-media-id="707726">
<img alt="A statue of Lord Kelvin, seated with a notebook, stands in a leafy park. An orange traffic cone is placed on his head like a hat. " height="960" loading="lazy" src="/sites/default/files/styles/960_x_960_limit/public/images/2024/05/07/lord_kelvin_with_a_traffic_cone.jpeg?itok=sKtlQ_up" typeof="foaf:Image" width="717">
</div>
<figcaption class="nist-image__caption">This statue of Lord Kelvin in Glasgow, Scotland, was adorned with a traffic cone, as other statues have been. It’s believed to be a nod to the Scottish sense of humor.<div class="nist-image__credit">
<span class="nist-image__credit-label">Credit:</span>
L. Kauffman/NIST
</div></figcaption>
</figure>
<h2>Thermometers</h2><p class="MsoNormal">Another interesting research pursuit here at NIST is trying to use atoms or molecules to build a thermometer that actually measures temperature.&nbsp;</p><p class="MsoNormal">You may be wondering what I mean.&nbsp;</p><p class="MsoNormal">After all, you probably have multiple thermometers in and around your home, and they all give you some number in either Fahrenheit or Celsius. But the truth is <a>they all&nbsp;</a><a href="/how-do-you-measure-it/how-do-you-measure-air-temperature-accurately" data-entity-type="node" data-entity-uuid="5642f2cb-4ba5-4901-bc25-8aa6cadcea45" data-entity-substitution="canonical" title="How Do You Measure Air Temperature Accurately?">measure some <em>other</em> physical quantity</a> <span>—</span> like the resistance of a platinum wire or the voltage generated between two dissimilar metals <span>—</span> that depends on temperature.&nbsp;</p><p class="MsoNormal">For these devices to read out a temperature in Fahrenheit or Celsius, they must be calibrated. NIST does such calibrations, and it’s more likely than not that the calibration for the thermometer in your home’s thermostat can be traced through a complicated set of steps all the way back to NIST.</p><p class="MsoNormal">But we may be able to make this whole calibration process simpler by making thermometers that directly measure temperature, using techniques that Lord Kelvin would appreciate.&nbsp;</p><p class="MsoNormal">For example, my colleague <a href="/people/daniel-barker" data-entity-type="node" data-entity-uuid="f2b0bbe0-f311-4a0f-88f6-8811579ddc25" data-entity-substitution="canonical" title="Daniel Barker">Daniel Barker</a> and I are working on using lasers to measure the distribution of velocities of a gas of rubidium atoms at room temperature and above. This technique, called Doppler thermometry, gets at the very heart of how Lord Kelvin understood temperature.&nbsp;</p><p class="MsoNormal">Together with my colleague <a href="/people/eric-norrgard" data-entity-type="node" data-entity-uuid="82071e64-2a73-4868-a4f1-f1a7d21f9aee" data-entity-substitution="canonical" title="Eric Norrgard">Eric Norrgard</a>, I am also working on two projects trying to create a <a href="/programs-projects/platform-realizing-integrated-molecule-experiments-prime" data-entity-type="node" data-entity-uuid="55f7f778-9a6c-461e-929e-d52d21d53f9c" data-entity-substitution="canonical" title="Platform for Realizing Integrated Molecule Experiments (PRIME)">new type of infrared thermometer</a> using atoms and molecules. If these efforts are successful, calibrating our thermometers could get much easier, and it may further other scientific advancements as well.&nbsp;</p><h2>Keeping It (Very) Cool in the Lab<strong>&nbsp;</strong></h2><p class="MsoNormal">I came to NIST as a postdoctoral researcher in 2012 after finishing my graduate work at Yale University.&nbsp;</p><p class="MsoNormal">As a postdoc, I worked with some of the coldest stuff in the universe: <a href="/news-events/news/2014/02/hysteresis-quantized-bec-superfluid" data-entity-type="node" data-entity-uuid="f5479391-37cb-4c53-8d08-ab21e96841e5" data-entity-substitution="canonical" title="Hysteresis in a Quantized BEC Superfluid">Bose-Einstein condensates</a> (BECs). Like the CAVS, BECs are also made of laser-cooled atoms, but they have been cooled even further to less than 100 billionths (!) of a degree above absolute zero.&nbsp;</p><p class="MsoNormal">After my postdoc, I decided to stay at NIST and try to use my experience with ultracold atoms and lasers to realize practical and useful standards, like the CAVS.&nbsp;</p><p class="MsoNormal">I gain a great sense of pride when I see what appear to be glowing balls of ultracold atoms <span>—</span> which are certainly fun to play with <span>—</span> used to solve real-world measurement problems. I suspect that Lord Kelvin may have felt the same sense of pride to see his measurements and theories regarding thermodynamics (which were probably also fun to work on) be applied to make more efficient steam engines.</p><h2>Happy Birthday, Lord Kelvin<strong>&nbsp;</strong></h2><p class="MsoNormal">Lord Kelvin didn’t just calculate absolute zero. After his early work in establishing absolute temperature scales, he was instrumental in laying the <a href="https://www.sciencemuseum.org.uk/objects-and-stories/how-perseverance-laid-first-transatlantic-telegraph-cable">first telegraph cables</a> across the Atlantic Ocean. Lord Kelvin also invented a machine that predicted tides and a compass that helped the Royal Navy <a href="https://www.rmg.co.uk/collections/objects/rmgc-object-42898">navigate the seas</a>. While my research is not quite that varied, one of the ways I mix up my work is by working at both room temperature and temperatures near absolute zero.</p><p class="MsoNormal">One of the key things I have learned is that measuring temperature, as Lord Kelvin understood it, is almost always harder than you might think. While the ideas are straightforward, making them work in practice is the real challenge.&nbsp;</p><p class="MsoNormal">And this fact makes it even more impressive that Lord Kelvin accurately predicted the temperature of absolute zero … in 1848.&nbsp;</p><p class="MsoNormal">On his 200th birthday, I’ll take a moment to appreciate that.</p>
</div>
</div>
<div
class="nist-block"
>
<div class="nist-tags">
<a href="/blogs/taking-measure/categories/249051">Metrology</a>,
<a href="/blogs/taking-measure/categories/2746606">Metric</a>,
<a href="/blogs/taking-measure/categories/249111">Pressure and vacuum metrology</a>,
<a href="/blogs/taking-measure/categories/249116">Thermometry metrology</a>,
<a href="/blogs/taking-measure/categories/249241">Physics</a> and
<a href="/blogs/taking-measure/categories/249246">Atomic / molecular / quantum</a></div>
</div>
<div
class="nist-block"
>
<h2
class="nist-block__title"
>About the author</h2>
<div class="nist-field nist-field--label-hidden entity-reference">
<div class="nist-field__items">
<div class="nist-field__item">
<article
about="/blogs/taking-measure/authors/stephen-eckel" class="nist-teaser"
>
<div class="nist-teaser__image">
<div class="entity-reference"> <a href="/blogs/taking-measure/authors/stephen-eckel" hreflang="en"><img loading="lazy" src="/sites/default/files/styles/thumbnail/public/images/2020/09/11/stephen-eckel.jpg?itok=FtSaXUTP" width="67" height="100" alt="Stephen Eckel" typeof="foaf:Image" />
</a>
</div>
</div>
<div class="nist-teaser__content-wrapper">
<header>
<h3 class="nist-teaser__title"><a href="/blogs/taking-measure/authors/stephen-eckel"><span>Stephen Eckel</span>
</a></h3>
</header>
<div class="nist-teaser__content">
<div class="text-with-summary"><p>Stephen Eckel is a physicist in the Sensor Science Division. His research focuses on using atoms, both at room temperature and ultracold, to probe thermodynamic quantities like pressure and temperature in calibration-free ways. He earned his Ph.D. at Yale University in 2012 and came to NIST as a postdoctoral researcher working with Bose-Einstein condensates. When not in the lab working with atoms and lasers, you will most likely find him tending to his garden or driving antique Stanley Steam cars.</p></div>
</div>
</div>
</article>
</div>
</div>
</div>
</div>
<div
class="nist-block no-print"
>
<h2
class="nist-block__title"
>Comments</h2>
<section>
<article data-comment-user-id="0" id="comment-155216" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="">Michael Moldover</span></span>
on
<span class="nist-comment__date">June 26, 2024 11:30 AM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1719416875"></mark>
</p>
<div class="nist-comment__permalink"><a href="#comment-155216">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>For your amusement: Baron Kelvin&#039;s name comes from the River Kelvin which flows past Glasgow into the River Clyde. <a href="https://en.wikipedia.org/wiki/River_Kelvin">https://en.wikipedia.org/wiki/River_Kelvin</a></p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/155216">Reply</a></li></ul>
</div>
</article>
<article data-comment-user-id="0" id="comment-155221" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="">Jeremy Davis</span></span>
on
<span class="nist-comment__date">June 26, 2024 11:46 AM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1719416894"></mark>
</p>
<div class="nist-comment__permalink"><a href="#comment-155221">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>Great article, but I had a couple of nits to pick. First, Celsius temperature was referred to as &quot;centigrade&quot; during the time period referenced (and is still incorrectly called centigrade by a significant number of people today). While I think that should be acknowledged to give historical context, I would support NIST and other bureaus of weights and measures internationally putting forth a greater effort to purge &quot;centigrade&quot; from everyday language(s) in the present day. Second, was the scale of what is now called the Celsius thermometer not inverted when originally proposed, so that water boiled at 0 °C and froze at 100 °C? I think that would make an interesting article all by itself.</p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/155221">Reply</a></li></ul>
</div>
</article>
<div class="indented">
<article data-comment-user-id="0" id="comment-155361" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="">Stephen Eckel</span></span>
on
<span class="nist-comment__date">July 8, 2024 10:08 AM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1720447875"></mark>
<span class="nist-comment__parent">| Replied to <a href="/comment/155221#comment-155221" class="permalink" rel="bookmark" hreflang="en">Great article, but I had a…</a></span>
</p>
<div class="nist-comment__permalink"><a href="#comment-155361">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>Indeed, you are correct on both counts. The International Committee of Weights and Measures (abbreviated in French as CIPM) resolved in 1948 that &quot;degree Celsius&quot; is the preferred name (see <a href="https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf">https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf</a>). I should have been more careful in my editing. Second, while Celsius did indeed propose the scale 1742 with the inversion you describe, by the nineteenth century, the scale we know today with 0 °C being the freezing point and 100 °C had been well established.</p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/155361">Reply</a></li></ul>
</div>
</article>
</div>
<article data-comment-user-id="0" id="comment-155231" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="" content="Debasis Bandyopadhyay">Debasis Bandyopadhyay</span></span>
on
<span class="nist-comment__date">June 26, 2024 3:13 PM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1719429318"></mark>
</p>
<div class="nist-comment__permalink"><a href="#comment-155231">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>Thank you Stephen. Very nicely written article which addresses a critical subject in the needy hours of Quantum Computing &amp; Quantum sensors. I am going to share this article in my LinkedIn post.</p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/155231">Reply</a></li></ul>
</div>
</article>
<article data-comment-user-id="0" id="comment-155306" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="">Jason</span></span>
on
<span class="nist-comment__date">July 2, 2024 3:50 PM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1719952638"></mark>
</p>
<div class="nist-comment__permalink"><a href="#comment-155306">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>Good information and really cool (pun intended), but you didn&#039;t answer your pivotal question: How low can temperature go? Are we challenging absolute zero - or is the better title: How close to absolute zero can we get? In either case, I&#039;d love to hear your thoughts on the both questions.</p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/155306">Reply</a></li></ul>
</div>
</article>
<div class="indented">
<article data-comment-user-id="0" id="comment-155356" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="">Stephen Eckel</span></span>
on
<span class="nist-comment__date">July 8, 2024 9:32 AM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1720446797"></mark>
<span class="nist-comment__parent">| Replied to <a href="/comment/155306#comment-155306" class="permalink" rel="bookmark" hreflang="en">Good information and really…</a></span>
</p>
<div class="nist-comment__permalink"><a href="#comment-155356">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>Excellent question! The third law of thermodynamics states that while one can never reach absolute zero, there is no fundamental limit as to how close you can get. To the best of my knowledge, the lowest temperatures obtained are about 50 pK, for use in a tall &quot;atom fountain&quot; (see <a href="https://arxiv.org/pdf/1407.6995">https://arxiv.org/pdf/1407.6995</a>). After the atoms are cooled to these low temperatures, they are accelerated upwards such that they fly 10 m up and 10 m back down. Such experiments can measure inertial forces very accurately, and need such low temperatures to prevent the cloud from expanding too much during its 10 m up-and-down flight. So, to return to your question, we are challenging absolute zero, but how close we get is really a practical limit: it ultimately depends on what temperature a given experiment needs.</p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/155356">Reply</a></li></ul>
</div>
</article>
</div>
<article data-comment-user-id="0" id="comment-156831" class="nist-comment js-comment">
<footer class="nist-comment__info">
<p class="submitted">
<span class="nist-comment__author"><span lang="" typeof="schema:Person" property="schema:name" datatype="">Serenity Jonson</span></span>
on
<span class="nist-comment__date">November 6, 2024 8:54 PM</span>
<mark class="hidden nist-comment__new" data-comment-timestamp="1730984439"></mark>
</p>
<div class="nist-comment__permalink"><a href="#comment-156831">Permalink</a></div>
</footer>
<div class="nist-comment__content">
<div class="text-long"><p>In this passage it is talking about temperature and how you need different temperatures for different experiments .</p>
</div>
<ul class="links inline nist-comment__links">
<li class="comment-reply nist-comment__link">
<a href="/comment/reply/node/1847761/comment_node_blog/156831">Reply</a></li></ul>
</div>
</article>
<h2>Add new comment</h2>
<link rel="stylesheet" media="all" href="/sites/default/files/css/css_Lx5yvw0vUi4TN7C0L-5Rdrp4Q049mXEKn-dXREWOtBs.css?delta=0&amp;language=en&amp;theme=nist_www&amp;include=eJxLzCvJTMov0U-E0Hpp-UW5OsmJBSXJGYn6SYnFqTppmTklqUX6KUWlBYk5ehAeAD47FNs&amp;exclude=eJx1UAuuwyAMuxAdR0IBsi5bIBWfdb39QrunVZOeRFDsWI7BQ3i4JnoW67-9u1fj_xlRkGxmkZnRQQbeGoVqfwmTqTZ3JeWirJkFomtFbSjPdoZjXKkhpaXIE-0vMSLsXLthQt0s7KG4JNFGquDVmCk_TN1qw6QJK-56O7N44HM_fazsDSFi-YNuXdez-oSHBF9tLLCx9AX48oHmSbhWu98XDdMZTV0gaWUr_tprgKaUBAJ2CSPByEbBMGzSm9PwQZ9XNisZg_Bh6O49LSrP_bCeBp4G_kZLFIqMH3oD_KWsjg" />
<form class="comment-comment-node-blog-form comment-form usa-form antibot" novalidate="novalidate" data-drupal-selector="comment-form" data-action="/comment/reply/node/1847761/comment_node_blog" action="/antibot" method="post" id="comment-form" accept-charset="UTF-8">
<noscript>
<div class="antibot-no-js antibot-message antibot-message-warning">You must have JavaScript enabled to use this form.</div>
</noscript>
<div class="form-item js-form-item form-type-textfield js-form-type-textfield form-item-name js-form-item-name">
<label for="edit-name" class="usa-label">
Your name
</label>
<input data-drupal-default-value="Anonymous" data-drupal-selector="edit-name" type="text" id="edit-name" name="name" value="" size="30" maxlength="60" class="form-text usa-input" />
</div>
<input data-drupal-selector="form-u5csfrhbeu4n7flphzdoqvrqizdsdt1ejp7hvutaply" type="hidden" name="form_build_id" value="form-U5csfRhbEU4n7fLPhZDoqvrqizdsDT1eJp7hvUtaPlY" class="usa-input" /><input data-drupal-selector="edit-comment-comment-node-blog-form" type="hidden" name="form_id" value="comment_comment_node_blog_form" class="usa-input" /><input data-drupal-selector="edit-antibot-key" type="hidden" name="antibot_key" value="" class="usa-input" /><div class="field--type-text-long field--name-comment-body field--widget-text-textarea js-form-wrapper form-wrapper" data-drupal-selector="edit-comment-body-wrapper" id="edit-comment-body-wrapper"> <div class="js-text-format-wrapper js-form-item form-item">
<div class="form-item js-form-item form-type-textarea js-form-type-textarea form-item-comment-body-0-value js-form-item-comment-body-0-value">
<label for="edit-comment-body-0-value" class="usa-label form-required">
Comment
<span class="usa-label--required"> <span class="usa-sr-only">Required</span>*</span></label>
<div class="form-textarea-wrapper">
<textarea class="js-text-full text-full form-textarea required usa-textarea resize-vertical" data-entity_embed-host-entity-langcode="en" data-media-embed-host-entity-langcode="en" data-drupal-selector="edit-comment-body-0-value" id="edit-comment-body-0-value" name="comment_body[0][value]" rows="5" cols="60" placeholder="" required="required" aria-required="true"></textarea>
</div>
</div>
<div class="js-filter-wrapper filter-wrapper hidden js-form-wrapper form-wrapper" data-drupal-selector="edit-comment-body-0-format" id="edit-comment-body-0-format"><div class="js-filter-guidelines filter-guidelines js-form-wrapper form-wrapper" data-drupal-selector="edit-comment-body-0-format-guidelines" id="edit-comment-body-0-format-guidelines"><div data-drupal-format-id="plain_text">
<h4>Plain text</h4>
<ul>
<li>No HTML tags allowed.</li>
<li>Web page addresses and email addresses turn into links automatically.</li>
<li>Lines and paragraphs break automatically.</li>
</ul>
</div>
</div>
</div>
</div>
</div>
<fieldset data-drupal-selector="edit-captcha" class="captcha captcha-type-challenge--image">
<legend class="captcha__title js-form-required form-required">
CAPTCHA
</legend>
<div class="captcha__element">
<input data-drupal-selector="edit-captcha-sid" type="hidden" name="captcha_sid" value="652108456" class="usa-input" /><input data-drupal-selector="edit-captcha-token" type="hidden" name="captcha_token" value="xA9eEFiHOxwF3wLddRj0Zab1D_DBsw_65CwTTXqYBDU" class="usa-input" /><div class="captcha__image-wrapper js-form-wrapper form-wrapper" data-drupal-selector="edit-captcha-image-wrapper" id="edit-captcha-image-wrapper"><img data-drupal-selector="edit-captcha-image" src="/image-captcha-generate/652108456/1741073254" width="180" height="60" alt="Image CAPTCHA" title="Image CAPTCHA" loading="lazy" typeof="foaf:Image" />
</div>
<div class="form-item js-form-item form-type-textfield js-form-type-textfield form-item-captcha-response js-form-item-captcha-response">
<label for="edit-captcha-response" class="usa-label form-required">
What code is in the image?
<span class="usa-label--required"> <span class="usa-sr-only">Required</span>*</span></label>
<input autocomplete="off" data-drupal-selector="edit-captcha-response" aria-describedby="edit-captcha-response--description" type="text" id="edit-captcha-response" name="captcha_response" value="" size="15" maxlength="128" class="form-text required usa-input" required="required" aria-required="true" />
<div id="edit-captcha-response--description" class="description help-block">
Enter the characters shown in the image.
</div>
</div>
</div>
<div class="captcha__description description">This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.</div>
</fieldset>
<div data-drupal-selector="edit-actions" class="form-actions js-form-wrapper form-wrapper" id="edit-actions"><input data-drupal-selector="edit-submit" type="submit" id="edit-submit" name="op" value="Save" class="button button--primary js-form-submit form-submit usa-button" /></div>
<div class="comments__disclaimer padding-top-2">
<em>Please be respectful when posting comments. We will post all comments without editing as long as they are appropriate for a public, family friendly website, are on topic and do not contain profanity, personal attacks, misleading or false information/accusations or promote specific commercial products, services or organizations. Comments that violate our comment policy or include links to non-government organizations/web pages will not be posted.</em>
</div>
</form>
</section>
</div>
</div>
<aside class="nist-page__region nist-page__region--sidebar-second tablet-lg:grid-col-4">
<div>
<div
class="nist-block"
>
<div>
<div about="/blogs/taking-measure">
<div
class="nist-block no-print"
>
<h2
class="nist-block__title"
>Our Science in Your Inbox</h2>
<div class="text-long"><p>Subscribe to our weekly emails.</p>
<form action="https://public.govdelivery.com/accounts/USNIST/subscribers/qualify" accept-charset="UTF-8" method="post">
<input name="utf8" type="hidden" value="&#x2713;">
<input type="hidden" name="authenticity_token" value="GleKn0r3EFkuIRsIWsyLN6Mrqim4qc3U7eIUCWGqBFz2ziQ/qv0gnQTJUhVbKHMSlmrsC7UHIm6S8IfK6qk9EQ==">
<input type="hidden" name="topic_id" id="topic_id" value="USNIST_309">
<div class="grid-row grid-gap-1">
<div class="tablet:grid-col-8">
<label class="usa-sr-only" for="email">Enter Email Address</label>
<input class="usa-input" type="text" name="email" id="email" title="email" placeholder="Your Email Address">
</div>
<div class="tablet:grid-col-4">
<input type="submit" name="commit" value="Sign Up" class="usa-button margin-top-1">
</div>
</div>
</form>
</div>
</div>
<div
class="views-exposed-form usa-form filters nist-block" novalidate="novalidate" data-drupal-selector="views-exposed-form-search-blog-taking-measure-search-page"
>
<h2
class="nist-block__title"
>Search</h2>
<form action="/blogs/taking-measure/search" method="get" id="views-exposed-form-search-blog-taking-measure-search-page" accept-charset="UTF-8" class="usa-form">
<div class="form-item js-form-item form-type-textfield js-form-type-textfield form-item-k js-form-item-k form-no-label">
<input placeholder="Search this blog" data-drupal-selector="edit-k" type="text" id="edit-k" name="k" value="" size="30" maxlength="128" class="form-text usa-input" />
<div id="edit-k--description" class="description help-block">
Put exact phrase in quotes (e.g., "artificial intelligence")
</div>
</div>
<div class="grid-col-12 form-actions js-form-wrapper form-wrapper" data-drupal-selector="edit-actions" id="edit-actions"><input data-drupal-selector="edit-submit-search-blog" type="submit" id="edit-submit-search-blog" value="Search" class="button js-form-submit form-submit usa-button" /></div>
</form>
</div>
<div
class="nist-block no-print"
>
<h2
class="nist-block__title"
>Stay connected</h2>
<div><a href="https://www.facebook.com/nist" class="nist-social nist-social--facebook" title="Facebook" ><span>Facebook</span></a><a href="https://www.linkedin.com/company/nist" class="nist-social nist-social--linkedin" title="LinkedIn" ><span>LinkedIn</span></a><a href="https://www.x.com/nist" class="nist-social nist-social--x" title="X (Twitter)" ><span>X (Twitter)</span></a><a href="https://www.youtube.com/nist" class="nist-social nist-social--youtube" title="Youtube" ><span>Youtube</span></a><a href="https://www.instagram.com/nist/" class="nist-social nist-social--instagram" title="Instagram" ><span>Instagram</span></a><a href="https://public.govdelivery.com/accounts/USNIST/subscriber/new?topic_id=USNIST_309" class="nist-social nist-social--envelope" title="GovDelivery" ><span>GovDelivery</span></a></div>
</div>
<div
class="views-element-container nist-block"
>
<h2
class="nist-block__title"
>Categories</h2>
<div><div class="js-view-dom-id-0f9f01bda434500586c658647eedbafa599ec30066749291f7821047cd147cf4">
<div>
<select class="usa-select ViewsJumpMenu js-viewsJumpMenu" title="-- Choose --" id="blog-categories-takingm-jump-menu">
<option>-- Choose --</option>
<option data-url="/blogs/taking-measure/categories/249466">Advanced communications</option>
<option data-url="/blogs/taking-measure/categories/248321">Bioscience</option>
<option data-url="/blogs/taking-measure/categories/248371">Buildings and Construction</option>
<option data-url="/blogs/taking-measure/categories/248416">Chemistry</option>
<option data-url="/blogs/taking-measure/categories/248486">Electronics</option>
<option data-url="/blogs/taking-measure/categories/248531">Energy</option>
<option data-url="/blogs/taking-measure/categories/248561">Environment</option>
<option data-url="/blogs/taking-measure/categories/248586">Fire</option>
<option data-url="/blogs/taking-measure/categories/248616">Forensic Science</option>
<option data-url="/blogs/taking-measure/categories/248651">Health</option>
<option data-url="/blogs/taking-measure/categories/249421">Information technology</option>
<option data-url="/blogs/taking-measure/categories/2748236">Infrastructure</option>
<option data-url="/blogs/taking-measure/categories/248866">Manufacturing</option>
<option data-url="/blogs/taking-measure/categories/248946">Materials</option>
<option data-url="/blogs/taking-measure/categories/249011">Mathematics and statistics</option>
<option data-url="/blogs/taking-measure/categories/249051">Metrology</option>
<option data-url="/blogs/taking-measure/categories/249126">Nanotechnology</option>
<option data-url="/blogs/taking-measure/categories/249451">Neutron research</option>
<option data-url="/blogs/taking-measure/categories/249426">Performance excellence</option>
<option data-url="/blogs/taking-measure/categories/249241">Physics</option>
<option data-url="/blogs/taking-measure/categories/249461">Public safety</option>
<option data-url="/blogs/taking-measure/categories/249456">Resilience</option>
<option data-url="/blogs/taking-measure/categories/249341">Standards</option>
<option data-url="/blogs/taking-measure/categories/2813456">Technology transfer</option>
<option data-url="/blogs/taking-measure/categories/249396">Transportation</option>
</select>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</aside>
</div>
</div>
<div class="grid-container">
</div>
</section>
</div>
<div data-elastic-exclude>
<!-- nist-index-ignore-start -->
<footer class="nist-footer padding-bottom-4">
<div class="grid-container nist-footer__info">
<div class="grid-row">
<div class="tablet:grid-col-6">
<div class="nist-footer__logo">
<a href="/" title="National Institute of Standards and Technology" rel="home">
<img class="nist-footer__logo-img" src="/libraries/nist-component-library/dist/img/logo/NIST-Logo-Brand-White.svg" alt="National Institute of Standards and Technology logo" width="300px" height="42px" />
</a>
</div>
<div class="nist-footer__contact">
<h3 class="nist-footer__contact-heading">HEADQUARTERS</h3>
<address>
100 Bureau Drive<br>
Gaithersburg, MD 20899<br>
<a href="tel:301-975-2000">301-975-2000</a>
</address>
<p>
<a href="mailto:do-webmaster@nist.gov">Webmaster</a> | <a href="https://www.nist.gov/about-nist/contact-us">Contact Us</a> | <a href="https://www.nist.gov/visit">Our Other Offices</a>
</p>
</div>
</div>
<div class="tablet:grid-col-6">
<div class="nist-footer__social-links">
<a class="nist-social nist-social--x-white" href=" https://x.com/NIST">
<span>X.com</span>
</a>
<a class="nist-social nist-social--facebook-white" href=" https://www.facebook.com/NIST">
<span>Facebook</span>
</a>
<a class="nist-social nist-social--linkedin-white" href=" https://www.linkedin.com/company/nist">
<span>LinkedIn</span>
</a>
<a class="nist-social nist-social--instagram-white" href=" https://www.instagram.com/nist/">
<span>Instagram</span>
</a>
<a class="nist-social nist-social--youtube-white" href=" https://www.youtube.com/NIST">
<span>YouTube</span>
</a>
<a class="nist-social nist-social--giphy-white" href=" https://giphy.com/nist">
<span>Giphy</span>
</a>
<a class="nist-social nist-social--rss-white" href=" https://www.nist.gov/news-events/nist-rss-feeds">
<span>RSS Feed</span>
</a>
<a class="nist-social nist-social--envelope-white" href=" https://public.govdelivery.com/accounts/USNIST/subscriber/new">
<span>Mailing List</span>
</a>
</div>
<div class="nist-footer__feedback">
How are we doing? <a class="usa-button" rel="nofollow" href="/form/nist-gov-feedback?destination=/blogs/taking-measure/how-low-can-temperature-go-lord-kelvin-and-science-absolute-zero" title="Provide feedback">Feedback</a>
</div>
</div>
</div>
</div>
<div class="grid-container">
<div class="nist-footer__nav" role="navigation">
<ul>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/privacy-policy">Site Privacy</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/oism/accessibility">Accessibility</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/privacy">Privacy Program</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/oism/copyrights">Copyrights</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.commerce.gov/vulnerability-disclosure-policy">Vulnerability Disclosure</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/no-fear-act-policy">No Fear Act Policy</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/office-director/freedom-information-act">FOIA</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/environmental-policy-statement">Environmental Policy</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/summary-report-scientific-integrity">Scientific Integrity</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.nist.gov/nist-information-quality-standards">Information Quality Standards</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://www.commerce.gov/">Commerce.gov</a>
</li>
<li class="nist-footer__menu-item">
<a href="http://www.science.gov/">Science.gov</a>
</li>
<li class="nist-footer__menu-item">
<a href="http://www.usa.gov/">USA.gov</a>
</li>
<li class="nist-footer__menu-item">
<a href="https://vote.gov/">Vote.gov</a>
</li>
</ul>
</div>
</div>
</footer>
<!-- nist-index-ignore-end -->
</div>
</div>
<script type="application/json" data-drupal-selector="drupal-settings-json">{"path":{"baseUrl":"\/","pathPrefix":"","currentPath":"node\/1847761","currentPathIsAdmin":false,"isFront":false,"currentLanguage":"en"},"pluralDelimiter":"\u0003","suppressDeprecationErrors":true,"back_to_top":{"back_to_top_button_trigger":100,"back_to_top_speed":1200,"back_to_top_prevent_on_mobile":false,"back_to_top_prevent_in_admin":true,"back_to_top_button_type":"image","back_to_top_button_text":"Back to top"},"google_analytics":{"account":"G-HEQ0YF2VYL","trackOutbound":true,"trackMailto":true,"trackTel":true,"trackDownload":true,"trackDownloadExtensions":"7z|aac|arc|arj|asf|asx|avi|bin|bsh|c|csv|doc(x|m)?|dot(x|m)?|dw(fx|g|gd)|dxf|eps|epub|exe|f(90)|flv|gif|gz|gzip|hqx|jar|jpe?g|js|m1v|mp(2|3|4|e?g)|mobi|mov(ie)?|msi|msp|pdf|phps|pl|png|ppt(x|m)?|pot(x|m)?|pps(x|m)?|ppam|sld(x|m)?|thmx|qtm?|ra(m|r)?|rfa|rtf|rvt|sch|sea|sit|swf|tar|tgz|tif|txt|txz|wav|wma|wmv|wpd|wrl|xls(x|m|b)?|xlt(x|m)|xlam|xml|xsd|z|zip"},"nist_search":{"clickTracking":"search-report-click","isDebug":false,"clickTrackEnabled":true,"message":"NIST Search in debug mode. Check the browsers network inspector for Click Track reporting results..."},"data":{"extlink":{"extTarget":false,"extTargetNoOverride":false,"extNofollow":false,"extNoreferrer":false,"extFollowNoOverride":false,"extClass":"ext","extLabel":"(link is external)","extImgClass":false,"extSubdomains":true,"extExclude":"\\.gov\\\/|\\.mil\\\/|\\manufacturingusa\\.com\\\/","extInclude":"","extCssExclude":".ck-editor, .nist-video-thumbnail__lightbox-trigger, a.nist-icon--mail-blue","extCssExplicit":"","extAlert":true,"extAlertText":"Thank you for visiting NIST. We hope your visit was informative. We have provided a link to this site because it has information that may be of interest to our users. NIST does not necessarily endorse the views expressed or the facts presented on this site. Further, NIST does not endorse any commercial products that may be advertised or available on this site. Click OK to be directed to your link.","mailtoClass":"0","mailtoLabel":"(link sends email)","extUseFontAwesome":false,"extIconPlacement":"after","extFaLinkClasses":"fa fa-external-link","extFaMailtoClasses":"fa fa-envelope-o","whitelistedDomains":[]}},"viewsJumpMenu":{"blog-categories-takingm-jump-menu":{"new_window":false}},"ajaxTrustedUrl":{"\/blogs\/taking-measure\/search":true,"\/comment\/reply\/node\/1847761\/comment_node_blog":true},"user":{"uid":0,"permissionsHash":"bd6a443844dbe99b4e6942f3b1397526e760137efd2b1ee6b2d588fc414dff20"},"antibot":{"forms":{"comment-form":{"id":"comment-form","key":"8s3HerPNUiBWAup-NU0eICdfN5XSJ1VRGAW7gyEytXD"}}}}</script>
<script src="/sites/default/files/js/js_jDaFaXhHm6gPUKstNYX9eIyoQXghVs3g7rbR0QoqpYY.js?scope=footer&amp;delta=0&amp;language=en&amp;theme=nist_www&amp;include=eJxdkAuOwyAMRC8E9ZGQCQ51CzgCp2lvX8hHu6qEBG8Yz0j2OD2dSj8L-L-3ezQTRWIihwXTR3lq8CuYwk3dzF0LspUkGJzWHsIlQsTju7ES56XKi-BXGC27pnfK1HsleawuS4DADX0PTlyeuwdiEo_JniNwJwxUL3Tbtv1z0FvHIIS6LphuJ5pJcqail3yi9R_7YtqoHskZY-GZJzPE5h5rXlz3rbCzHWwHGyzKXhTO-zZLzaavQ6leFQd9AQAFjIc"></script>
<script src="https://siteimproveanalytics.com/js/siteanalyze_6017546.js" async></script>
<script src="/sites/default/files/js/js_phYs2jDctfdGpas0b2o3STtb7Y4B0bPDz-8rro3OgSg.js?scope=footer&amp;delta=2&amp;language=en&amp;theme=nist_www&amp;include=eJxdkAuOwyAMRC8E9ZGQCQ51CzgCp2lvX8hHu6qEBG8Yz0j2OD2dSj8L-L-3ezQTRWIihwXTR3lq8CuYwk3dzF0LspUkGJzWHsIlQsTju7ES56XKi-BXGC27pnfK1HsleawuS4DADX0PTlyeuwdiEo_JniNwJwxUL3Tbtv1z0FvHIIS6LphuJ5pJcqail3yi9R_7YtqoHskZY-GZJzPE5h5rXlz3rbCzHWwHGyzKXhTO-zZLzaavQ6leFQd9AQAFjIc"></script>
<script type="text/javascript">window.NREUM||(NREUM={});NREUM.info={"beacon":"bam.nr-data.net","licenseKey":"37b7ccb661","applicationID":"1089704227","transactionName":"YFxUN0sADEdYVkBaClkWdwBNCA1aFnFGRhVWVWoNVgUHaHpaWkcXWFVaBks9LFtdUGJaAEB6WQ1NEw1YVVBGHltBUFMU","queueTime":4,"applicationTime":590,"atts":"TBtXQQMaH0k=","errorBeacon":"bam.nr-data.net","agent":""}</script></body>
</html>
Reference in a new issue View git blame Copy permalink