Making Poo: Modeling the Digestive System
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Body Systems, Enzymes and Digestion, Food Science and Nutrition
Alternative titles: Digestive System in Action
Summary
Students create a hands-on model of the digestive system using everyday materials to show how food is broken down, nutrients are absorbed, and waste is excreted as poo. This activity helps students visualize and understand the stages of digestion and the role of each organ.
Procedure
- Place 50 ml of vinegar into a plastic sandwich bag to represent stomach acid.
- Break up a cracker and part of a banana into pieces and place them in the bag to represent chewed food.
- Add 50 ml of water to represent saliva, seal the bag, and squeeze out the air.
- Mash the mixture by hand for 2–3 minutes to model the stomach churning food into chyme.
- Cut a small hole in the corner of the bag and squeeze the contents into a stocking over a tray, modeling food entering the small intestine.
- Continue squeezing until the liquid drains out, representing nutrient absorption into the bloodstream.
- Optional: Squeeze the mix in a sponge to remove more liquids, representing the large intestine.
- Cut off the toe of the stocking and push the remaining solids into a cup with a hole in the bottom to represent the large intestine.
- Push the solids through the hole in the cup into the tray to model excretion of waste as poo.
Links
How to Make Poo : A Food Digestion Demonstration for kids - Danny Nicholson : Think Bank Education:
Making Poo:The Digestive System - O2LearnThinkBig:
📄 Making Poo - Telethon Kids institute: https://discoverycentre.thekids.org.au/siteassets/pdfs/poo-and-you/for-teachers/8---lesson-plan---making-poo-final.pdf
Variations
- Add food coloring to represent digestive juices from the liver, gallbladder, or pancreas.
- Use different foods (e.g., bread, fruit) to show how various types break down.
- Extend the activity with a drama performance where students act as different organs in the digestive system.
Safety Precautions
- Cover tables with plastic sheets or newspaper to contain mess.
- Students should wash hands thoroughly after the activity.
- Use safety scissors for cutting the bag and stocking.
- Do not eat any food used in the demonstration.
Questions to Consider
- What happens to food when we eat it? (It is broken down into smaller pieces, digested, and nutrients are absorbed.)
- Why does food look so different when it becomes poo? (It has been chemically and physically broken down, nutrients removed, and waste remains.)
- Where do nutrients from food go after digestion? (They are absorbed into the bloodstream and carried to where the body needs them.)
- What gets left behind after digestion? (Waste materials and substances the body cannot use.)
- How does each part of the digestive system contribute to digestion?
- What might happen if one part of the digestive system didn’t exist? (Certain steps of digestion or nutrient absorption would not occur properly.)
- Why do scientists study poo? (To learn about gut bacteria, digestion, and health.)