3 Perplexing Physics Problems

Why does shaken soda explode? Does ice melt first in fresh or salt water?
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This video features experiments that have been shown to me by science teachers over the years. Does ice melt fast in salt water or fresh water was an experiment introduced to me at the Utah Science Teachers' conference. The ring of metal over a chain demo came from a teachers event in Florida. The idea shaking a carbonated drink increases pressure came from an email.

Special thanks to Petr Lebedev for building the pressure gauge.

Links to literature are below:
Victims of the pop bottle, by Ted Willhoft. New Scientist, 21 August 1986 p.28

Carbonation speculation
The Physics Teacher 30, 173 (1992); https://doi.org/10.1119/1.2343501

Agitation solution
The Physics Teacher 30, 325 (1992); https://doi.org/10.1119/1.2343556

Filmed by Cristian Carretero, Jordan Schnabel, Jonny Hyman, and Raquel Nuno

Music from https://epidemicsound.com "Seaweed" "Quietly Tense" "Mind Shift" "Observations"