For a science project focusing on the digestive system, kids can make a model stomach and a model small intestine. They can also make a wide array of digestive components, but the stomach and small intestine are the easiest and most enjoyable for children.
Children can use a plastic sandwich bag, crackers of any type and orange juice to recreate a stomach environment. To create the effect that chewing has on crackers, students can crumble them up with their hands. The crackers will then be placed into the plastic bag that is representing the stomach. Pouring orange juice into the plastic bag will be the symbol for the stomach acid. Students can note how the orange juice made the cracker pieces soft. By squeezing the bag with their hands, students can replicate the stomach contractions that are in the digestive system. This project results in the crackers and orange juice mixture becoming completely liquid, as it would in the stomach.
To create a science project for the small intestine, students will need one leg of pantyhose, 2 cups of cooked oatmeal, scissors and something to cover up the work surface. An adult should cut the pantyhose so that there is a hole in each end. The student can then pour the two cups of oatmeal into the pantyhose and observe how it flows slowly through the "intestine." By squeezing the pantyhose, the student can recreate the effect of the small intestine contractions which will cause the oatmeal to flow through the pantyhose more quickly.