21 grams experiment
The idea that a soul weighs 21 grams has been mentioned in many media. For example, in a 2013 issue of the manga Gantz, a 2013 podcast of  Welcome to Night Vale, the 2015 movie The Empire of Corpses a 2021 episode of Ted Lasso, and a 2023 issue of the manga One Piece. There are also songs called “21 Grams” that talk about the weight of a soul. These songs were released by Looptroop Rockers (2005), Niykee Heaton (2015), Fedez (2015), August Burns Red (2015), Thundamentals (2017) and Arena (2022). Travis Scott mentioned the idea in his 2018 song “No Bystanders”. MacDougall and his experiments are talked about in the 1978 documentary movie Beyond and Back, and episode five of the season one of Dark Matters: Twisted But True. A made-up American scientist named “Mr. MacDougall” is in Gail Carriger's 2009 novel Soulless. Mr. MacDougall is an expert in measuring souls.