Children can learn about what happens inside the body to the food they eat and get hands-on instruction to reinforce the knowledge taught. Use the opportunity to reinforce healthy eating habits. Teach them the importance of the nutrients received through food and how it relates to health and nutrition. Explain the entire process, including what happens to leftover food the body doesn't use.
The digestive process begins in the mouth. Have the child make a model of the human mouth they can use to explore the process of digestion in the mouth. Use a mould of the upper and lower teeth to make a model using plaster of Paris. Connect the upper and lower teeth by attaching a hinge so the parts are movable. Let the child experiment with different foods to see how the food reacts with the teeth. Have a squirt bottle on hand to spray in the mouth to simulate saliva. Discuss what foods take longer than others to break down in the mouth.
A diagram of the digestive tract makes a craft appropriate for many grade levels. Have the child cut out large and small intestines, stomach and oesophagus shapes using construction paper. Glue the shapes in the appropriate order onto poster board. Discuss the mechanics of the digestive system. Give the child a broad overview of what happens to food while they do the craft. Encourage the child to ask questions about the digestive process.
This craft idea will get the child engaged in the process of the digestive system while allowing them to get their hands messy. Give the child three petri dishes. Use a variety of easily mashed foods such as various berries. Cut up fruit into bite-size pieces and place into the first dish. Have the child mash the fruit a little bit and put it in the second dish. Mash the food completely and place in the third dish. Encourage the child to mash the fruit as much as possible using her hands. Discuss the stages of digestion with the child and when the breakdown of food happens inside the body as they go through the process of 'digesting' the food.
A balloon and water make a craft to use while discussing the process of stomach digestion. Fill a clear balloon about half way with water. Have the child put in strips of paper and blow the balloon up the rest of the way. Tie off the balloon. Let the child document what happens to the paper as time passes. Discuss with the child what happens inside the stomach and how stomach acid breaks down food. Discuss what happens if you eat too much food or if you eat bad food.