How My Stomach Works

Children will experiment with what happens to food when they eat it.


Lesson Objective

Children will perform an experiment to understand how the body processes the food we eat.


What You'll Need

  • Cookies or crackers – 2 per child (at least!)
  • Water
  • Sandwich-size zip close bags – 2 per child
  • Paper plates – 1 per child

What To Do

  1. Discuss with the children information about where food goes when we eat it (see Did You Know?).
  2. Tell the children that they will perform an experiment to find out how the stomach digests food.
  3. Distribute the bags and cookies or crackers to the children.
  4. Show the children how to place 1 cookie or cracker into each bag and zip it closed.
  5. Have the children squeeze 1 of the bags, breaking up the cookies or crackers into small pieces (representing chewing the food with your teeth). Repeat with the other bag.
  6. Add enough water to the contents of one of each child’s bags to make the mixture into a thin liquid (representing digestive juices from the stomach).
  7. Have the children continue to mix and churn the bag with the water, representing the stomach action.
  8. Next, cut a very small hole in the bottom corner of the bag of dry ingredients. Have the children try to squeeze the dry ingredients onto the plate.
  9. Cut a small hole in the bottom corner of the bag with the water (this bag represents the stomach), squeezing the liquid mixture onto the plate.
  10. Discuss which of the bags was easier to squeeze so that the ingredients would come out onto the plate, and discuss the important job of the stomach (see Guiding Student Inquiry).

Guiding Student Inquiry

  • Tell me what your teeth do with food when it is in your mouth.
  • Describe how your food gets to your stomach.
  • Explain what happens to food when it gets to your stomach.

Explore, Extend & Integrate

  • Make an experiment with the children by providing different textures of foods for them to try chewing and swallowing, such as bananas, peanut butter, and dry wheat cereal. Discuss which foods are easier to swallow.
  • Make a batch of muffins from a dry mix with the children. Discuss what happens to the consistency of the dry mix by adding the liquid.

Check for Children’s Understanding

  • Could children explain what their teeth do with food?
  • Could children explain what the stomach does with the food?
  • Could children understand what might happen to food without the assistance of digestive juices?


Did You Know?

Every time you take a bite of food, your body starts the process of breaking the food down into something useful for your body. You take a bite, and your teeth grind up the food to make it small enough to swallow. Your saliva mixes with the food in your mouth to help it slide down your throat. Next, the muscles in your throat squeeze the food, like a toothpaste tube, into your stomach.

Your stomach works like a mixer, churning and mashing the food into even smaller pieces. In the stomach, the food is mixed with digestive juices to help it move on to the next step. The food continues to your intestines to allow the vitamins, minerals, protein, and other good stuff from the food to be used by your body. This entire process can take a whole day or sometimes 2 days to complete! 

Vocabulary: Child-Friendly Definitions

  • stomach – the organ in the body that processes food.
  • digestive juices – any or all of the fluids produced by the body to digest food.
  • mixer – a device used for mixing things together.
  • churn – to move or stir with great force.
  • squeeze – to press firmly together.
  • saliva – a liquid produced in the mouth that helps people process food.

Lesson Tips

  • Some of the children may be hungry; provide extra cookies or crackers to share with the children for a small snack before performing the experiment.
  • Be sure that the holes you cut in the corners of the bags are very small holes; by doing this, you are ensuring that the dry ingredients are more difficult to squeeze out of the bags.


  • Where Does Your Food Go? by Wiley Blevins
  • What Happens to a Hamburger? by Paul Showers
  • How Do Dinosaurs Eat Their Food? by Jane Yolen
  • Eat Your Peas, Louise! by Pegeen Snow

Home School Resources

Home educators: use these printable lesson PDFs to teach this lesson to your home schoolers. They're available in English and Spanish.

Home/School Connections

Las Conexiones a la Casa

While we believe that the books and resources recommended may be of value to you, keep in mind that these are suggestions only and you must do your own due diligence to determine whether the materials are appropriate and suitable for your use. PNC has no sponsorship or endorsement agreement with the authors or publishers of the materials listed.

Content Provided By

Common Core State Standards Initiative – These lessons are aligned with the Common Core State Standards ("CCSS"). The CCSS provide a consistent, clear understanding of the concepts and skills children are expected to learn and guide teachers to provide their students with opportunities to gain these important skills and foundational knowledge [1]. Visit the CCSS