Body Systems: Digestive System: Digestion in a Bag
Students model both mechanical and chemical digestion with simple materials.
Each student needs a zip-top bag, one or two crackers (saltines work well) and a small amount of soda.
The crackers are placed in the bag.
Students smash the crackers to represent mechanical digestion - breaking apart the food.
A small amount of soda is added to the bag. After observing for a few moments, students and squish the contents of the bag. The soda contains acid, like your stomach does, which helps break down the food even further. Once the food has been turned into a slurry, it is ready to be passed on to the intestines.