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Digestive System Lesson

Updated on November 6, 2015

This is part 4 of a 7 part hands-on unit study on anatomy of the human body. Demonstrate how each part of the digestive system works using crackers and pantyhose, create teeth molds, prepare and eat a salad while discussing healthy eating habits, and more! These lessons are geared toward 4th-5th grade level children and their siblings. They were created by another creative mom for our weekly homeschool co-op. We meet each week for 2 1/2 hours and have 16 children between the ages of 1-13. Use these fun lessons with your classroom, family, camp, after school program, or co-op!

Types of Teeth Photo Credit: http://www.childrenshospital.org
Types of Teeth Photo Credit: http://www.childrenshospital.org

Your Teeth

1. Pray. Read & discuss Matthew 6:25-34.

2. Review the other human body systems and introduce the digestive system.

3. Mechanical digestion starts in the mouth. The teeth grind up the food with the help of the strongest muscle in the body, the masseter.

Play-dough teeth mold
Play-dough teeth mold
Using Plaster of Paris to make permanent teeth molds (optional)
Using Plaster of Paris to make permanent teeth molds (optional)

Teeth Molds

4. Make your own tooth cast/mold. Have the children roll up a small ball of play-dough/clay into a small cylinder. Wrap the clay in syran wrap and then form it into a U-shape. Place it in their mouth and then bite down once so that your teeth leave an imprint. Ask children what they notice about their teeth from their imprints.
-If you would like to make permanent molds, unwrap the clay from the syran wrap and place it on a piece of aluminum foil. Fold up the sides of the aluminum foil around the clay to catch any Plaster of Paris. Mix some plaster of Paris with water. Place 1-2 spoonfuls on each mold and let the children push the plaster around so that it covers all the teeth marks. Don't spread it too thin or it will break when you remove the clay later. Set it aside to dry. After about 10 minutes, the molds should be ready to remove from the clay.
YOU WILL NEED: play-dough/clay, syran wrap, aluminum foil (if making permanent molds), prepared plaster of Paris (if making permanent molds), & disposable spoons (if making permanent molds)

If you need ideas on what to say...

Exploring Creation with Human Anatomy and Physiology (Young Explorer Series)
Exploring Creation with Human Anatomy and Physiology (Young Explorer Series)

Throughout this lesson, when describing various parts of the digestive system and what they do, I based what I said on what I read from this book. The author does a great job of explaining advanced parts about the human body in terms that children can easily understand. The book is written in a conversational manner rather than like a dry textbook, so my children actually enjoy reading it and listening to it. If you can only get one book for this unit, this is the best option.

 
Using different teeth to bite and chew apples
Using different teeth to bite and chew apples

5. If you are not limited by time, read "I Know Why I Brush My Teeth" by Kate Rowan.

6. Have the children use mirrors to look at their teeth. Then have them touch the tips of their various teeth as you go through the names and purposes of each of them. The shape of each type of tooth is perfectly created for its function. The incisors are sharp and used for biting. The cuspids/canines are sharp and used for tearing food. The flat premolars and molars in the back are used for grinding food. Have children bite and chew an apple slice using only their incisors, cuspids, and then molars. What do they notice? Then have bite and chew an apple slice the way they normally do and focus on which teeth they are using and when.

YOU WILL NEED PER CHILD: 2 apple slices, a napkin, & a mirror (such as a compact mirror)

I Know Why I Brush My Teeth (Sam's Science)
I Know Why I Brush My Teeth (Sam's Science)

This is a fun book that is presented as a back-and-forth conversation between a son and his mother. Types of teeth, basic parts of the tooth, and taking care of your teeth (plaque) are all mentioned and explained. "How Many Teeth?" by Paul Showers is another good, basic picture book on teeth.

 
Showing different types of teeth (compliments of the "Tooth Fairy" who has been saving her child's teeth)
Showing different types of teeth (compliments of the "Tooth Fairy" who has been saving her child's teeth)

7. Discuss the parts of a tooth (enamel, dentin, pulp, gum root, and blood vessels.) and briefly discuss each part as children color and label (optional) a worksheet that shows the parts of a tooth. Afterward, pass around a tooth and point out the various parts:

YOU WILL NEED: crayons or markers, coloring sheets that show the parts of a tooth such as the one from enchantedlearning.com (unlabeled - good for children who want to write and can write quickly) or the one from abcteach.com (labeled - good for children who don’t want to write), and one of more teeth (Ask families if they've saved a tooth that fell out from one of their children.)


Digestive System Worksheets

8. If you are not limited by time, have the children paste together the parts of the digestive system. You can use the free printable parts of the digestive system worksheets found in the Appendix L (pp. 22-23) of http://www.coreknowledge.org , or you can use the pieces from Considering God's Creation. Discuss the names of the organs and their functions as you glue them on.

YOU WILL NEED: glue sticks, scissors, and digestive system pieces from coreknowledge.com and paper or worksheets from Considering God's Creation

Eagle's Wings Considering God's Creation (A Creative Biblical Approach to Natural Science)
Eagle's Wings Considering God's Creation (A Creative Biblical Approach to Natural Science)

This is a great addition to every science unit! It is so easy to follow, and it has excellent worksheets that encourage children to really study God's creation. We have used the flower and tree field guide identification worksheets, the human body anatomy cut-and-paste activities, and more. This is something I would recommend to everyone!

 
Saliva demo on starches and proteins using crackers and cheese
Saliva demo on starches and proteins using crackers and cheese

Saliva and Tongue.

9. Ask children when they think their bodies begin breaking down food. Most people think the process begins in the stomach. It begins in your mouth! Not only does mechanical digestion begin in the mouth, but so does chemical digestion. Mechanical digestion is chewing food into smaller pieces. Let children chew up and swallow a cracker. Chemical digestion is breaking down food into small chemical components so your body can use it. Amylase in your saliva starts to break down the starches in sugars. Have the children suck on a saltine cracker and let it dissolve. Ask, "Do you think this happens with all foods?" Pass out a pieces of cheese and have the kids suck on it. Sugar/carbohydrates will dissolve partly in your mouth from your saliva, but protein has to be chewed to digest it.

YOU WILL NEED: crackers and cheese

10. Briefly mention how the tongue forms the food into a ball called a bolus and moves it into your esophagus Show a picture of a tongue magnified in order to see the parts that actually push the bolus back.

YOU WILL NEED: a picture of the tongue that has been magnified


Peristalsis activity with a sock (esophagus) and a ball (bolus)
Peristalsis activity with a sock (esophagus) and a ball (bolus)

Esophagus and Peristalsis

11. Ask if anyone has ever laughed so hard that they had milk come out of their nose or if they swallowed something quickly and then had to cough it up because "it went down the wrong pipe." This usually doesn't happen because under normal circumstances after you swallow your food, your epiglottis closes up over your windpipe/trachea that leads down to your lungs and your soft palate lifts up to block the way to your nose. Have everyone use their tongues to feel their soft palate on the roof of their mouth.

12. Ask children how they think food travels down through their esophagus. It's not gravity. Have children each get a mouthful of water, touch their toes (so they are upside-down), and swallow the water. You can stills wallow when you're upside-down. Food travels through your digestive system by peristalsis, which is wave-like muscle contractions.

YOU WILL NEED: cups of water

13. Demonstrate peristalsis by having the children put 1-3 balls in the foot of a long sock and then pushing them down through the sock.

YOU WILL NEED PER CHILD: a long sock (such as a soccer sock or tube sock) and 1-3 balls that fits snugly in the sock (such as baseballs)

Chyme in the stomach made using vinegar and crackers and a sandwich bag
Chyme in the stomach made using vinegar and crackers and a sandwich bag

Stomach

14. You food then travels to your stomach, which is like a plastic bag. When it is empty, it is like a crumpled up bag. [Show a crumpled up plastic bag.] When food enters it, your stomach unfolds and opens up. [Show an open plastic bag.] The stomach also has 2 holes just like the plastic bag. The holes are called sphincters. The one at the top lets the bolus in, and the one at the bottom lets the digested bolus (now called chyme) into the small intestine. The stomach lining produces gastric juices, which everyone has tasted when they have thrown up. Some of the gastric juices include hyrdochloric acid and protein-digesting pepsin. Not only do the gastric juices further digest the food, but they also kill harmful bacteria so that they don't make you sick. Hand each child a sandwich bag. They should pour in the small amount of vinegar water (which will represent our gastric juices) and a few crackers. They can mash them around a bit. The crackers should dissolve into what we now call chyme.

YOU WILL NEED: 1 plastic bag with a small hole in the bottom, 1 ziplock sandwich bag per child, 1 cup of vinegar water (1 Tbsp. vinegar + 1/4 c. of water) per child, and 5 crackers per child

15. Briefly mention how bases offset acids. Your stomach has acids in it. When you have an upset stomach, it may be due to your stomach producing too much acid. That's why a cup of milk or an anti-acid tablet like Tums, which is high in calcium, might help.

Digestive Juices

Bile Breaks fat into Blobs.

The chief stomach enzyme is pepsin: Picture an Indian Chief drinking Pepsi to help his digestion.

Parietal cells (the first letter of each word): Produce Acid, Release Intrinsic factor, ET AL.

Good Picture Book on the Digestive System

The Quest to Digest
The Quest to Digest

Of all the picture books we read, this provided the most detailed information about the digestive system. The illustrations were enjoyable enough that even my 3 year old enjoyed listening to the book.

 
Holding a 20 foot rope to show the length of the small intestine
Holding a 20 foot rope to show the length of the small intestine

Small Intestines

16. Next your food goes into your small intestines. Your small intestines are about 20 feet long. Ask for 2 volunteers. Have the volunteers hold each end of a 20 feet long piece of yarn, string, or rope. Ask, "How does that fit inside your body?" It's all wrapped up. Your large intestine is about 5 feet long. Why is your small intestine called "small"? It has a smaller diameter compared with your large intestine. Your small intestine is divided into 3 parts: the duodenum (the first food which is where most of the chemical digestion occurs), jejunum (the next 8 feet), and the ileum. The jejunum and ileum are where most of the nutrients are absorbed into your blood.

YOU WILL NEED: 20 feet long piece of yarn, string, or rope with a string tied to it to mark the first foot (to show the length of the duodenum) and a string tied to it to make 8 feet later (to show the length of the jejunum)

Small intestine activity using pantyhose and sponges (for villi)
Small intestine activity using pantyhose and sponges (for villi)
A duster glove with "fingers" that can show what villi would look like
A duster glove with "fingers" that can show what villi would look like

17. Your small intestine absorbs the nutrients after your stomach and pancreas have broken them down. The inside of your small intestine is covered with villi, which are kind of like absorbent fingers. (If you have a duster with fingers, like the one in the photo on the right, you can show it to the children so they can get an idea of what villi would look like.) To demonstrate this, use a 12 inch long piece of pantyhose to represent the small intestine. Have the children work in pairs to first stuff cut up bits of a kitchen sponge (representing villi) into the pantyhose. Have each pair combine their sandwich bag of chyme (so that they are working with one stomach). Then use scissors to cut open a pyloric sphincter on their stomach bag to allow the cracker/vinegar chyme goo drip through. One child can hold open the pantyhose while the other child holds the stomach sandwich bag. They should hold them over a disposable bowl. Emphasize that the sponges/villi are absorbing the liquids and then distributing the nutrients throughout your body. Again, your food mush is moved through the intestines by peristalsis.

YOU WILL NEED FOR EACH PAIR OF CHILDREN: 12 inch piece of pantyhose, 4- 8 small bits of kitchen sponges, a disposable bowl, and scissors and just to show the group: a duster with "fingers" (optional)

Large intestines absorbing the water activity
Large intestines absorbing the water activity

Large Intestines

18. Finally what is left moves through the large intestine, where water is removed and whatever is leftover (feces) is stored until you have a bowel movement. Give each pair of children a few sheets of paper towels and have them absorb the water from their disposable bowls. This water will go back into your body. What is left will go into the toilet. A trash can will represent the toilet, so children can put everything in the toilet and then wash their hands.

YOU WILL NEED: paper towels

19. Review how the digestive system works asking the children about each of the parts and what activities we did today to represent those parts.

YOU WILL NEED: a picture of the digestive system from a book or from on-line

Bowels

Just remember the market news: Dow Jones Industrial Averages Closing Stock Report = Duodenum, Jejunum, Ileum, Appendix, Colon, Sigmoid, & Rectum.

(Cecum is left out but this will help you remember the rest.)

(http://www.valuemd.com/physiology.php)

Good Picture Books on the Digestive System

Gurgles and Growls: Learning About Your Stomach (The Amazing Body)
Gurgles and Growls: Learning About Your Stomach (The Amazing Body)

This has illustrations that keep the attention of all my children (ages 2-9) and has a decent enough amount of information to make it worthwhile to read to all of them.

 
A Journey through the Digestive System with Max Axiom, Super Scientist (Graphic Science)
A Journey through the Digestive System with Max Axiom, Super Scientist (Graphic Science)

My boys especially love this series written in comic book style (graphic). It's one step up from the Magic School Bus series.

 

Healthy Eating

20. If you are not limited by time, read "Did You Eat Your Vitamins Today?" by Ena Sabih, "Eat Healthy, Feel Great" by William Sears, or other book discussing how to eat healthy. Briefly discuss how important a healthy diet is to help your body function properly.

Eat Healthy, Feel Great
Eat Healthy, Feel Great

The labels foods as red light (unhealthy = don't eat), yellow light (okay to eat in moderation), and green light (healthy = eat all you want) foods. Of all the books we read on healthy eating, this is the one that really stuck with my 5 year old. Months later he continued to ask, "This is a green light food, isn't it?" This is good for early elementary and preschool children.

 
Healthy salad
Healthy salad

21. Discuss the food groups and nutrients of each of the salad components, and allow children to create and eat their own salads. If you're not limited by time, have the children help to prepare fruits, vegetables, hard-boiled eggs, etc. for the salad.) Also provide cups of water. We mentioned food groups, macro-nutrients (proteins, carbohydrates, fats, and water), and vitamins in each of the food items.

YOU WILL NEED: plates, forks, cups for water, large bowls, tongs, ingredients for a salad (options include: lettuce, broccoli, cucumbers, carrots, bell peppers, cherry tomatoes, strawberries, apples, shredded cheese, diced deli meat, diced egg, walnuts, croutons, and salad dressing)

More Good Picture Books on Healthy Eating

"Did You Eat Your Vitamins Today?" by Ena Sabih, "Showdown At The Food Pyramid" by Rex Barron, "Oh the Things You Can Do That Are Good for You! (Cat in the Hat's Learning Library)" by Tish Rabe, "The Vegetables We Eat" by Gail Gibbons, & "The Edible Pyramid" by Loreen Leedy are also fun picture books on healthy eating.

Good Enough to Eat: A Kid's Guide to Food and Nutrition
Good Enough to Eat: A Kid's Guide to Food and Nutrition

This is a nice introduction to healthy eating for early elementary and preschool children.

 
Stories of the Discovery of Vitamins: The Young Doctors Collection
Stories of the Discovery of Vitamins: The Young Doctors Collection

This is a great picture book about the discovery of vitamins written in a manner that is engaging to children but still providing plenty of factual information.

 

Favorite Books on the Digestive System

"Why Do We Eat?" by Stephanie Turnbull is another good picture book. "Dr. Beaumont and the Man with a Hole in his Stomach" by Sam Epstein is a good chapter book for elementary aged children.

The Magic School Bus Inside the Human Body (Magic School Bus (Pb))
The Magic School Bus Inside the Human Body (Magic School Bus (Pb))

All of my children (ages 2-9) enjoyed this book as Ms. Frizzle and her class travel through Arnold's digestive system and some other parts inside his body.

 
What Happens to a Hamburger? (Let's-Read-and-Find-Out Science 2)
What Happens to a Hamburger? (Let's-Read-and-Find-Out Science 2)

All my children (ages 2-9) enjoyed this book and learned from it as you follow the food you ate through your digestive system.

 

Material List for the Lesson

*This list does not include materials for activities listed as "If you are not limited by time."

ITEMS FOR FAMILIES TO BRING PER CHILD:
-mirror (such as a compact mirror) that can be used for children to examine their teeth
-play-dough or clay (1/4 of a can of play-dough will be enough)
-a tooth (various types if you have them – such as baby teeth that have fallen out that you have saved) (optional)
-crayons, markers, or colored pencils
-a coloring sheet that shows the parts of a tooth such as http://www.enchantedlearning.com/subjects/anatomy/teeth/label/labeltooth.shtml (unlabeled - good for children who want to write and can write quickly) or http://www.abcteach.com/documents/diagram-tooth-labeled-11480 (labeled - good for children who don’t want to write)
-a long sock such as a tube sock (You can bring one for every 2 children if they can work in pairs.)
-a ball that will fit snugly in the sock and not fall out (You can bring one for every 2 children if they can work in pairs.)
-pair of scissors (1 per family)

ITEMS TO BRING TO SHARE WITH THE GROUP:
-syran wrap, aluminum foil (if making permanent molds), prepared plaster of Paris (if making permanent molds), & disposable spoons (if making permanent molds)
-PER CHILD: 2 apple slices, a napkin
-crackers and cheese
-a picture of the tongue that has been magnified
-cups of water
-1 plastic bag with a small hole in the bottom, 1 ziplock sandwich bag per child, 1 cup of vinegar water (1 Tbsp. vinegar + 1/4 c. of water) per child, and 5 crackers per child
-20 feet long piece of yarn, string, or rope with a string tied to it to mark the first foot (to show the length of the duodenum) and a string tied to it to make 8 feet later (to show the length of the jejunum)
-FOR EACH PAIR OF CHILDREN: 12 inch piece of pantyhose, 4- 8 small bits of kitchen sponges, a disposable bowl, and scissors and just to show the group: a duster with "fingers" (optional)
-paper towels
-a picture of the digestive system from a book or from on-line
-plates, forks, cups for water, large bowls, tongs, ingredients for a salad (options include: lettuce, broccoli, cucumbers, carrots, bell peppers, cherry tomatoes, strawberries, apples, shredded cheese, diced deli meat, diced egg, walnuts, croutons, and salad dressing)

Good Video Clips on the Digestive System

Ready for the next lesson?

Making an edible DNA model during Lesson 1: Cells and DNA
Making an edible DNA model during Lesson 1: Cells and DNA

Create edible DNA models, made models of the insides of bones, dissect deer organs, create a working model of the respiratory system, play immune system freeze tag, and more in this fun 7-8 lesson unit on human anatomy! (An optional lesson on genetics and DNA is included.)

  • Cells and DNA Lesson - This is part 1 of a 7 part hands-on unit study on anatomy of the human body. Create edible models of human cells and DNA, look at cheek cells under a microscope, and more!
  • Genetics Lesson – This is an optional but very worthwhile lesson for the Human Anatomy Unit Study. Use M&M's to determine genetic traits, extract DNA from a strawberry using normal household materials, create edible DNA strands using marshmallows and licorice, design dog breeds as you select alleles, and more in this fun lesson on Genetics!
  • Skeletal and Muscular Systems Lesson - This is part 2 of a 7 part hands-on unit study on anatomy of the human body. Create models of bone parts, use stickers to label the bones on your body, dissect soup bones, measure the range of motion of your joints, and more!
  • Nervous System Lesson - This is part 3 of a 7 part hands-on unit study on anatomy of the human body. Create a clay model of the brain, twist together a pipe cleaner neuron, train your reflexes, dissect a deer brain and a cow eyeball (optional), and more!
  • Digestive System Lesson - This is part 4 of a 7 part hands-on unit study on anatomy of the human body. Demonstrate how each part of the digestive system works using crackers, pantyhose, create teeth molds, prepare and eat a salad while discussing healthy eating habits, and more!
  • Circulatory System Lesson - This is part 5 of a 7 part hands-on unit study on anatomy of the human body. Walk through your circulatory system, create a blood model and fake movie blood, measure your heart rate, dissect a heart, and more!
  • Respiratory System Lesson - This is part 6 of a 7 part hands-on unit study on anatomy of the human body. Create a lung model, measure lung capacity, dissect a lung, play a respiratory relay race, and more!
  • Immune System Lesson - This is part 7 of a 7 part hands-on unit study on anatomy of the human body. Play immune system freeze tag, watch how germs spread, observe bacteria under a microscope, and more! These lessons are geared toward 4th-5th grade level children and their.
  • Human Body Unit Study Presentations and Field Trip Ideas - This is the culminating activity for the 7 part hands-on unit study on anatomy of the human body. Children presented game show themed games related to the human body or other creative presentations, and we had a systems-of-the-human-body-themed meal. Recipes are included! Also included are the field trips we attended during this unit.

Konos Volume III
Konos Volume III

Konos Curriculum

Would you like to teach this way every day?

Konos Curriculum

I use Konos Curriculum as a springboard from which to plan my lessons. It's a wonderful Christian curriculum and was created by moms with active children!

Konos Home School Mentor

If you're new to homeschooling or in need of some fresh guidance, I highly recommend Konos' HomeSchoolMentor.com program! Watch videos on-line of what to do each day and how to teach it in this great hands-on format!

© 2012 iijuan12

Comments, Questions, or Ideas? - Please leave a note to let me know you dropped by! I love getting feedback from you!

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    • DianaHarper LM profile image

      DianaHarper LM 5 years ago

      Thanks for the ideas. Liked. Pinned. Blessed by a Squid Angel.

    • Cari Kay 11 profile image

      Kay 5 years ago

      You have some terrific ideas here and as a homeschooling mom, they are ideas I'll use. Thank you!

    • KimGiancaterino profile image

      KimGiancaterino 4 years ago

      Excellent job!

    • Millionairemomma profile image

      Millionairemomma 4 years ago

      I loved these ideas!

    • Tamara14 profile image

      Tamara Kajari 4 years ago from Zagreb, Croatia, Europe

      All the classes in our schools should look exactly like this. Children are like sponges but they don't get enough to absorb due to the poor educational system in many countries including mine :( Excellent lens!

    • SailingPassion LM profile image

      SailingPassion LM 4 years ago

      Good info :-)

    • iijuan12 profile image
      Author

      iijuan12 4 years ago from Florida

      @SailingPassion LM: Thank you!

    • profile image

      dessertlover 4 years ago

      Interesting lens! Lots of good stuff here!

    • iijuan12 profile image
      Author

      iijuan12 4 years ago from Florida

      @dessertlover: Thank you!

    • alex89 lm profile image

      alex89 lm 4 years ago

      Unfortunately I am far too familiar with my digestive system, as I have Crohns and the doctors keep wanting to take videos and scans and everything else, but this is a great lens.

    • iijuan12 profile image
      Author

      iijuan12 4 years ago from Florida

      @alex89 lm: I'm sorry to hear about your struggle with Crohns. Thank you for visiting!

    • profile image

      Torrs13 4 years ago

      This was a cool lens! I have had digestive problems for the past 8 years so I think it's good to educate people on how the body acts during the normal process so they know if something is wrong or feels off.

    • iijuan12 profile image
      Author

      iijuan12 4 years ago from Florida

      @Torrs13: Thank you!

    • prosper168 profile image

      prosper168 4 years ago

      Wow, really love your lenses! They are just what I am looking for to teach my daughter science in a fun way! Thanks so much!

    • iijuan12 profile image
      Author

      iijuan12 4 years ago from Florida

      @prosper168: Great! Thank you!

    • profile image

      jamy-vo 3 years ago

      Awesome activities!! Thanks so much for sharing!!

    • iijuan12 profile image
      Author

      iijuan12 3 years ago from Florida

      @jamy-vo: You're welcome! Thank you for visiting!

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