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The Digestive System

So last week we were studying the Circulatory and Respiratory systems.  This week, we have moved on to the Digestive system.  (again, thank all that is good we are in life science...I am rockin' out the instruction here ;)  ) Though there is nothing revolutionary to report, these are all simple things that you can do in your own class during your unit.
We started with my favorite.....BrainPOP.  The video on the Digestive System has just enough information to give the kids a basic understanding of how it all works.  While they were watching, I had them labeling a little picture of the system in their science journals.

I realize not everyone has a subscription to BrainPOP, so I found these two videos on YouTube (and if you go here to Classroom Magic by my friend Selina, she has a great tutorial on uploading YouTube videos to a flash drive) 

During science lab, we modeled the process of digestion.  To do this model, you will need for each student/group of students:

2 baggies
tablespoon of water
shot glass size of orange juice

First, the students placed the cracker into the baggie and started to mash it up with their fingers.  This was the "mouth" part of digestion.  Then, adding water, we showed how the saliva makes the cracker mushy enough for the tongue to push it back into the esophagus. 

photo of an experiment dealing with the digestive system
Once it enters the stomach, acid interacts with the mush.  The kids then added the OJ.  The muscle action of the stomach is then shown by the kids "kneeding" the baggie.  For some of my kids, their bag began to leak..probably due to the previous grinding and the added acid.  We discussed how the stomach would do that too were it not for the special mucus.  To simulate the mucus, we just placed the baggie and all of its contents inside of a second baggie.  Leaking problem solved and the kids learned a bit about the power of the acid!

Next, we talked about how that all entered the small intestine and the nutrients were absorbed.  To demonstrate *why* the small intestine is all smushed up, I took a long piece of construction paper.  I told them to imagine it was the small intestine.  We thought back to math and our discussions on surface area.  It made sense to the kids that since the nutrients were passing over the small intestine, it would want the most surface area possible to grab the important food for the cells.  I then accordion folded the construction paper to show how much smaller it would become by being folded altogether.  In order to take up the same length as the orginal piece, I would need to use 3 more accordion folded strips.  That is 3 times the surface area to pick up nutrients.  The kids had this lightbulb moment right then and there!

Finally, the food moves into the large intestine.  I will warn you, this part was messy, gooey, and a bit gross....but the kids LOVED LOVED LOVED it.

I explained that once all the nutrients were sucked out of the chyme (the name of the stuff in the small intestine) all that was left was a watery mass of waste.  Well, we know from previous studies that our body is 70% water.  If we just got rid of all that water, we would be dehydrated in no time.  So the large intestine's job is to suck all that water back into the body.  I took some oatmeal that I had previously made to simulate the waste/water combination.  Then, I poured it into a pantyhose.  Using my own two hands, I squeezed out as much of the water as possible.  Here was the end product.

photo of showing the kids how the large intestine works

I told you, it came out looking gross...but the kids got the point.  The understood the main purpose of the large intestine, and we even were left with some waste to "eliminate" through the rectum.  And no, I did NOT demonstrate that ;)

5th grade
Finally, we put it all together by creating a model poster from this book Easy Make & Learn Projects: Human Body (Grades 2-4).  Again, just like with the circulation models, I left off the information parts, and had the kids research the information using their science and health books. 

So there you have it.  Some simple, yet effective ways to teach the digestive system.


  1. Oooo, this is such a fun idea! We used to teach the digestive system, but they are removing it from our curriculum next year and I am so bummed :( Simulations like these make the human body so much fun to learn!

    Thanks for the great YouTube links! I am your newest follower :)

    3rd Grade Thoughts

  2. Yes! Great idea, I'm super excited to do this with my class. I was looking for an activity to bring the concept to life and make it fun. : )

    Thanks so much!

  3. I love how you collected so many materials in one place! I love BrainPop, too :)

    Luckeyfrog's Lilypad

  4. Thanks so much for the shout out! By the way, these are the exact same things I did for digestion:) Wish we taught together!


  5. What a great lesson Steph!
    I will totally have to incorporate it into my Science curriculum next year. I love the model poster. Great way to recap it all.

    ❤ Mor Zrihen from...
    A Teacher's Treasure
    Teaching Treasures Shop

  6. I am teaching about the body next week so I will have to try out your ideas! And thank you for posting on TBA today! You are overflowing with creative ideas!

  7. I am doing this tomorrow! My students are excited for this hands on lab! Thanks for the great ideas.


  8. As a high school teacher who is going to do a health course this coming year, this information was spot on! Obviously, your audience is far younger than mine, but kids never outgrow good videos and hands-on demonstrations like these. Great launching point activity for our lesson on digestion and excretion - thank you for sharing it with us!

  9. your graphic organizers are so good. I like them,

  10. E Brochure iBrouchure with numerous exceptional capacity to make your undertaking intriguing. It tells the story and interactive.


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