Digestive System – Making Poop Lab/Demo
What is your measurable objective?
 Students will be able to describe the functions of the individual organs in the digestive
system.
 Students will be able to identify the interrelationships between the organ systems.
How are you going to “hook” the students?
Today we are going to make “poop”! Ask the students to list the 6 kinds of nutrients we need to
survive. See how many organs of the digestive system they can list without assistance.
What are the students going to do to master the objective?
Participate in the demo and complete the handout.
What are you going to do make sure the students master the objective (checking for
understanding, teaching strategies, etc.)?
Teacher will model the passage of food through the digestive system. Students will participate in
the demo by becoming the “organs” or “enzymes”.
Materials:
 Top of 2-liter or 20-oz bottle
 Paper towel cardboard tube
 Ziploc bags
 Cups
 Water
 Knife
 Raw food
 Food coloring
 Knee highs
 Scissors
 Paper towels
Procedure: **You can pick students to help you with the different stages**
1. Give each table of four a cup, a dropper of water, a spoon or knife and some raw food.
Have the students chop the food into pieces. They may add water from the dropper. (Try
to include food from different food groups. Be sure to have crackers or bread for bulk).
This stage is modeling food being chewed. Discuss the purpose of saliva and how it is
contains an enzyme that has already started breaking down the food . You can also say
this is a physical change since the food is being “crushed” by the teeth.
2. Connect a funnel (top of a 2-liter bottle) to a cardboard tube (paper towel roll) and a large
plastic bag (gallon size ziploc bag). These represent the back of the mouth, esophagus
and stomach. Have one person from each group dump the cup of “chewed” food down
the throat to mimic swallowing. Use a pushing action on the cardboard tube to simulate
perstalsis. At this point you can talk about acid reflux and heartburn if there is time.
3. Knead the food in the stomach for a moment then detach the back from the cardboard
tube for a better visual of the stomach action. Have different students add different
shades of food coloring for stomach acid, enzymes and mucus.
4. Once it is mixed, tell the students the mixture they have created is now called “chyme”
which will now enter the first part of the small intestines, the duodenum (sp?). Keep the
mixture in the bag but push it to one corner. Have one student add green food coloring
for the bile and discuss the importance of bile. What happens when someone has their
gall bladder removed? What do they have to limit in their diet? (fats) Add another color for
insulin and one last color for the other enzymes. Discuss with the students the
importance of insulin and the other enzymes, which come from the pancreas.
5. Cut a hole in the corner of the bag where the chyme is located and squeeze the mixture
into a leg of pantyhose. Students will be able to see the “nutrients” leaving the hose. This
mimics nutrients being absorbed by the villi which then pass the nutrients into the blood
vessels of the villi. You will get messy at this point so you might want to wear a lab coat
and gloves. Make sure you have plenty of paper towels on hand. You can also discuss
the various “noises” you hear during digestion. This info can be found at yucky.com.
6. Set the “small intestine” on a set of sponges or paper towels so that students can see the
drying action of the large intestine. The purpose of the lg. intestine is to absorb water so
discuss what happens if not enough water is absorbed (when you are sick and the
mixture moves through your system quickly)… you have diarrhea or when too much
water is absorbed…constipation. What is the doctor checking for when they push on your
stomach and lower abdomen? One reason is to see if you are “flowing” appropriately or if
you are constipated. If enough water is removed, it is possible to press semi-solid “feces”
out of the pantyhose. Feel free to pass around your creation so that students can see the
finished product. Students will often ask about the smell. You can find this info on
yucky.com as well.
Lastly, discuss what happens to the digestive system when you are in a fight/flight situation. The
blood from your digestive system decreases to be used elsewhere for oxygen. If time, discuss
how the nutrients you eat help various organs function along with the food pyramid.
How are the students going to prove to you that they have mastered the objective?
Exit card: Which organ do you think is the most important within the digestive system? Why?
Which is the least important? Why?
Digestive System – Making Poop Lab
Student Page
Warm-up:
1. List the 6 kinds of nutrients we need to survive:
2. List as many organs of the digestive system as you can, without using your book:
How Does Food Get Inside You? A Model Demonstration!
(Observe each step of the demonstration before you write anything.)
Describe what you saw in STEP 1:
1. Ingestion takes place when you put food in your ____________. Digestion also
begins in your ____________. Your ____________ and _____________ break up
the food. Your mouth also adds a watery substance called _____________ which
contains mucus and an enzyme called _____________ (which causes __________
to break down to _______________).
Describe what you saw in STEP 2:
2. It takes about _______ seconds for food to pass through your ______________ to
your stomach. Smooth (involuntary) muscles squeeze in waves of contractions,
called ___________________, which moves the food along.
Describe what you saw in STEP 3:
3. Food stays in your _____________ for about 4 hours, where it is mixed and has
acid, _______________ and ________________ added. It is now no longer called
food; instead it is called chime, which is a __________, watery ____________.
Describe what you saw in STEP 4:
4. Most of digestion takes place in the ___________________, the first part of the
small ________________. A greenish fluid called _____________ is added,
which acts like a __________________ to break down fats. Your ____________
adds insulin and other enzymes. By now, the chime has become a _________ of
molecules ready to be absorbed by the ___________ (tiny, finger-like projections)
of the _____________ _____________________. Molecules of nutrients pass
into the blood _____________ of the villi.
Describe what you saw in STEP 5:
5. The main job of the ____________ ___________________ is to ____________
the water from the undigested chime, which may stay in the large _____________
as long as _____ days, becoming more and more solid. Feces consist of solidified
wastes, mostly undigested __________________ and _________________.
Conclusion: Label the parts of the digestive system.
1. Your body processes food in 4 stages: ingestion, ________________, absorption
and _______________________.
2. Digestion is a process that breaks ___________ down into small pieces so that
they can be ________________, or taken into the ___________ of your body.
3. The major organs of your digestive tract include the mouth, _______________,
stomach, small __________________, __________ intestine, ___________ and
anus. Food passes through all of these. Your liver, _______________ and gall
______________ are also part of your digestive system, but never contain food;
they just add _______________ to your food.
4. Digestion is both mechanical (through chewing, mixing and separating into
smaller parts) and _____________ (through chemical changes).
5. Enzymes are _________________ that regulate _______________ digestion.
They are not __________________ during a chemical reaction.