--- 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 title: Google Doodle Honors The Chemist Behind The pH Scale image: https://static.time.com/v3/assets/bltea6093859af6183b/blt36386bf907cc0520/698931a94ee2621232311ef0/screen-shot-2018-05-29-at-10-49-00-am1.png?branch=production&width=1440&quality=75&auto=webp&crop=16:9 ---  * [Newsfeed](/tag/time-section-newsfeed/) ## Newsfeed Update your preferences in [Account Settings](/account/preferences/) Close # Google Doodle Celebrates S.P.L. Sørensen, the Trailblazing Chemist Behind the pH Scale ## 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](/author/casey-quackenbush/) ## Casey Quackenbush Update your preferences in [Account Settings](/account/preferences/) Close May 29, 2018 5:14 AM CUT  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](/author/casey-quackenbush/) ## Casey Quackenbush Update your preferences in [Account Settings](/account/preferences/) Close May 29, 2018 5:14 AM CUT How well do you remember the pH scale from chemistry class? Today’s Google Doodle [presents](https://www.google.com/doodles/celebrating-spl-srensen "undefined") 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 "undefined"), 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 "undefined") 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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