Today’s Google doodle honors the Danish chemist S.P.L. Sørensen.
As the head of Copenhagen’s Carlsberg Laboratory, Sørensen is known for inventing the pH scale to measure acidity and alkaline levels of substances and solutions.
Leading to a search for “S.P.L. Sørensen,” the animated doodle presents a tomato, an egg, broccoli, a lemon, soap and battery to quiz-takers, who must guess each object’s acidity level by clicking on the right or left arrows on either side of the illustrated Sørensen.
Born in Havrebjerg, Sørensen first studied medicine and then switched his studies to chemistry. His research around acidity levels involved the concentration of proteins and hydrogen within substances — thus the pH label. During his career, Sørensen worked in the Danish Polytechnic Institute lab and as a consultant for Denmark’s Royal Naval Dockyard.
The Google Doodle blog does not include any details on Sørensen or the doodle beyond where it is being shared. Today is not Sørensen’s birthday, so it’s a mystery why Google chose today to honor the chemist.