Digestion in a balloon

Discover how the digestive system breaks down what you consume

Discovery Place Nature

What is large, full of acid and digests food constantly? It’s your stomach! In this experience we will explore the major portions of the digestive system, which consists of multiple organs including the stomach, intestines and esophagus. Your digestive system breaks down food into very small particles until it can be absorbed into the body. It is also responsible for removing waste, otherwise known as poop.

In this experiment, we will learn the basics of the digestive system through a fun, hands-on activity that is very popular in our Explore More Me lab at Discovery Place Science.

This activity includes approximately 10 minutes of prep time and 30 minutes of learning. It is great for all ages.


  • A Balloon
  • Vegetable oil or Olive oil
  • Bread
  • Vinegar
  • Releasable/Reusable zip ties (or rubber band)


  1. Place 10 drops of oil into the balloon and spread it to create a lining inside of the balloon. This represent the mucus membrane layer of the stomach.
  2. Place the zip tie on the neck of the balloon, closest to the bulb. This represents the circular sphincter muscle.
  3. “Eat” the bread by adding it into the balloon. Once all of the bread is inside the balloon the stomach is “full.” (Well, maybe there’s still room for dessert!)
  4. Using a dropper, place 10 drops of vinegar (or 1 teaspoon if you add more bread) into the balloon. This represents stomach acid.
  5. Close the zip tie, then “digest” the food by gently mixing and mashing the contents of the balloon.
  6. The balloon models the stomach, rectum and intestines. Open the zip tie and squeeze the contents of the balloon onto the tray by starting at the largest part of the balloon. The digestion process is finished and the waste (poop) is on the tray.

How to adjust for younger and older learners

For younger kids, try different foods, like fruit, cheese and whole wheat bread to see how that changes the color and consistency of what comes out of the balloon. Also, challenge each other to use descriptive words to describe the consistency of each outcome.

For older kids and adults, consider the changes in how well your digestive system works. How would diarrhea be simulated? Add water to the balloon after the contents have been mashed. This would represent the large intestine that did not remove enough water. Now the end result will be more runny, like diarrhea. What would happen if we added less vinegar? The large intestines would remove too much water. The person would be constipated, and the result would be a drier product.


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