Gilbert's Pop Top-A Kid Favorite!


To observe how gas forms in a chemical reaction


  • Film container with snap lid (you can buy online if you can’t find a free one any longer)
  • Effervescent antacid tablet
  • Warm water


Break the antacid tablet into smaller pieces. Place one of the broken pieces into the film container. Fill the container about half full of water. Place the lid on the container. Place the container on the floor or a flat surface. Stand back and watch what happens!


The water causes the antacid to react. Carbon dioxide gas builds up pressure in the film canister until the lid pops off.