“WE ARE WASHINGTON: PEOPLE OF THE FAIR”LESSON ONE
Digestive Systems
Objective
Construct and analyze models of human and animal digestive systems.
Materials
• One resealable zippered plastic bag (such as Ziploc brand) per participant
• One piece of bread per participant
• One bottle of orange juice or cola (Additional bottles may be neededwith an increased number of participants. On average,
one two-liter bottle will work for 18 participants.)
• Optional: one 3 ounce cup (for holding liquid) per participant
• Paper towels (enough for each participant to have one regular sized piece, and for and cleanup after the lesson)
• Clock or stopwatch
• Trash bag
Preparation
1. Place one piece of bread in a resealable zippered bag for each participant.
2. Fill one 3 ounce cup full with liquid for each participant or plan on passing the bottle of cola or orange juice
around to participants.
Lesson
Discussion: Answer the following questions based on what you know and learned in the article:
• What is digestion and why is it important?
• What are the types of digestive systems explained?
• Which animals have digestive systems similar to humans’?
• What are the key differences between these two systems?
1.
Begin by passing out a resealable zippered bag with a piece of bread in it to each participant.
Explain that the bag is like a stomach: a muscle that contains and squeezes food.
2.
Pour about three ounces of orange juice or cola into the bag to act as the “digestive juices.”
3.
Once the bread and fluid are combined, have participants observe what begins to happen to the bread.
4. Ask participants what they see happening in their bag.
5.
Then, have participants predict what will happen if they squeeze their bags.
6.
Pass out a piece of paper towel to participants and have them place it around their bags so that they
cannot see what is happening.
7.
Have the participants gently squeeze the bag for two minutes. Participants need to be gentle to avoid
poking holes in the bag.
8.
While participants are squeezing their bags, ask them the following questions to review:
• What type of digestive system do humans have?
• What is a livestock species that has a similar stomach to humans?
• What type of digestive system do sheep and goats have?
• What is the difference between the ruminant and monogastric digestive system?
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