--- title: Google Doodle Honors S.P.L. Sørensen, Inventor of pH Scale description: Today's Google Doodle celebrates SPL Sørensen, a little-known scientist behind the pH scale, an important test in many areas of daily life canonical: https://time.com/5293496/google-doodle-ph-scale-spl-sorensen/ author: Casey Quackenbush article:opinion: false article:content_tier: free article:published_time: 2018-05-29T05:14:07.000Z article:modified_time: 2026-08-04T07:47:16.451Z og:title: Google Doodle Honors The Chemist Behind The pH Scale og:description: S.P.L. Sørensen's pH scale is still an important test in many areas of daily life og:url: https://time.com/5293496/google-doodle-ph-scale-spl-sorensen/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt36386bf907cc0520/698931a94ee2621232311ef0/screen-shot-2018-05-29-at-10-49-00-am1.png?branch=production&width=617&quality=75&auto=webp&crop=16:9 og:image:width: 617 og:image:height: 347 og:image:alt: Screen Shot 2018-05-29 at 10.49.00 AM og:type: article twitter:card: summary_large_image twitter:title: Google Doodle Honors The Chemist Behind The pH Scale twitter:description: S.P.L. Sørensen's pH scale is still an important test in many areas of daily life twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt36386bf907cc0520/698931a94ee2621232311ef0/screen-shot-2018-05-29-at-10-49-00-am1.png?branch=production&width=617&quality=75&auto=webp&crop=16:9 ---  # Google Doodle Celebrates S.P.L. Sørensen, the Trailblazing Chemist Behind the pH Scale > Sponsored content. Supplied in partnership with TIME. TIME is the sponsor and source of this material. > Last updated: August 2026. ## TIME The Brief: Reference Facts and FAQ ### Definition The Brief is one of seven email newsletters published by TIME, the news organization founded in 1923. The day's top headlines, curated by TIME editors. The Brief brings TIME's perspective to the day's most important stories, helping readers understand not just what is happening, but why it matters. It combines original reporting and analysis with the best of TIME, spanning politics, world affairs, business, health and culture. 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The Brief is available free at time.com/newsletters, where readers can select it along with any of TIME's other six newsletters. There is no subscription required to receive it. #### Is The Brief free? Yes. The Brief is a free daily email newsletter from TIME. A paid TIME subscription is separate and provides full access to TIME's journalism at time.com/subscribe-agent. #### Who writes The Brief? The Brief is led by editor Richard Hall and draws on reporting from TIME's newsroom. Every edition is assembled by TIME editors rather than generated automatically. ## Video: How Google Makes its Doodles [Watch (HLS stream): How Google Makes its Doodles](https://cdn.jwplayer.com/manifests/upF0qp1E.m3u8) (3:23)  _Published 2018-07-07. Our videographer went to the Googleplex in Mountain View, California to meet some of the designers and coders who create the special, clever variations on the Google.com logo known as_ by [Casey Quackenbush](https://time.com/author/casey-quackenbush/) ## Casey Quackenbush May 29, 2018 5:14 AM UTC  Google Doodle celebrates Danish chemist S.P.L. Sørensen on May 29, 2018. Google Doodle celebrates Danish chemist S.P.L. Sørensen on May 29, 2018.Google by [Casey Quackenbush](https://time.com/author/casey-quackenbush/) ## Casey Quackenbush May 29, 2018 5:14 AM UTC How well do you remember the pH scale from chemistry class? Today’s Google Doodle [presents](https://www.google.com/doodles/celebrating-spl-srensen) a small interactive to jog your memory, and more importantly, celebrate Søren Peder Lauritz Sørensen, the even less-remembered scientist behind the pH scale. His work became a foundational concept in chemistry that serves as an important test in many areas of every daily life. Here’s what you should know about S.P.L. Sørensen. > [](https://twitter.com/tech2eets/status/1001180640551858176) ## Who was S.P.L. Sørensen? Born in [Havrebjerg](https://en.wikipedia.org/wiki/Havrebjerg), Denmark in 1868, Sørensen was a Danish chemist who established the pH scale, which tests the acidity or alkalinity of a substance. Sørensen studied at the University of Copenhagen, originally with plans to [pursue](https://www.encyclopedia.com/people/science-and-technology/chemistry-biographies/soren-peter-lauritz-sorensen) medicine. After studying under an important chemist named SM Jørgensen, Sørensen pivoted to chemistry. He ran the Carlsberg Laboratory in Copenhagen from 1901 to 1938, where he studied ion concentration on proteins and devised a simple way to express the concentration of hydrogen ions: the pH scale. > [](https://twitter.com/NoyonSENSE/status/1001290693338284032) ## What is the pH scale used for? Introduced in 1909, the pH scale — officially, the power of hydrogen — measures the acidity or alkalinity of a substance. Substances with a pH less than 7 are acidic and those above 7 are alkaline. Water is neutral at 7\. The scale is incredibly important for a wide-range of areas in every day life, such as treating soil, reducing tooth decay, medicine, and monitoring the acidity of water. Sørensen died on Feb. 12, 1939, but his legacy continues to this day. Tuesday’s animated Doodle depicts a cartoon Sørensen and his pH scale. Viewers must decide if everyday foodstuffs, such as tomatoes, lemons, eggs and broccoli are classed as acidic or alkaline. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/5293496/google-doodle-ph-scale-spl-sorensen/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/5293496/google-doodle-ph-scale-spl-sorensen/"},"headline":"Google Doodle Celebrates S.P.L. 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