Human Digestion Demonstration Part 1 – Mushy Crackers

Do you really want to show your students what digestion looks like? These hands-on demonstrations below are extremely simple to do and show clearly what happens to food between the time it enters your mouth until it passes into your small intestine. The student reactions are great and when they’re done your course, they may forget many things but they will never forget the crackers & the bread in the bag demonstrations!

In this Post I will cover Demonstration #1 – Crackers in the mouth

This activity as well as others are found within my Human Digestion Lesson which can be found HERE. If you enjoy the activity please check it out.

This activity can also be found within my Biology Unit – Cells and Body SystemsClick HERE for a preview.

Demonstration #1 – Crackers in the mouth

Materials: Everyday crackers (2 per student)

This demonstration shows how your saliva a) works to break apart the bonds holding the cracker together and b) mixes with the food to produce a swallowable material.

Step 1 – Put a regular cracker into your mouth and chew. Record what it tastes like? Was it sweet? Plain? Hard? Soft? Etc.

Step 2 – Place a new cracker in your mouth and let it sit for 1.5 minutes before chewing and answer the following questions (number 2 should be answered at the 1 minute mark).

Observations – 1) What does it feel like initially? 2) What is feels like after 1 minutes in your mouth 3) What it feels like after 1.5 minutes in your mouth 4) What it feels like when you chew it?

Class discussion:

What was the main texture (feeling) difference in your mouth between chewing right away and waiting 1.5 minutes before chowing down?

Ask your students how mechanical digestion is shown in this demonstration as well.

Explain:

When the cracker is in your mouth, your saliva starts to break the bonds holding the cracker together as well as mix with it. This makes the cracker softer and easier to swallow. The act of chewing is the mechanical digestion as chewing helps to break the cracker into smaller pieces so that it’s easier to swallow. If your class advanced, you can mention that breaking something into smaller pieces also increases the surface area therefore, makes chemical digestion more efficient.
I have performed this demonstration many times and I’m telling you, the kids love it! They are totally grossed out, but they love it.

Click here to be directed to Part 2 of this post where I explain a demonstration which shows digestion in the remainder of the body.

This activity as well as others are found within my Human Digestion Lesson which can be found HERE. If you enjoy the activity please check it out.

This activity can also be found within my Biology Unit – Cells and Body Systems Click HERE for a preview.