Scientific Evidence and Secrets of the Stomach: A Fun Lesson for Students

To uncover a secret, scientists look for evidence.  Long ago, scientists investigated to find out how the stomach works. The scientists did some surprising things.  One investigated digestion by collecting stomach juices from a man with a hole leading to his stomach! The scientists did all of these things to find evidence about how the stomach breaks down food.

In the Seeds of Science/Roots of Reading® student book Secrets of the Stomach, the work of three scientists who investigated how the stomach digests food is described.  It outlines how each of them found evidence that added to the scientific community’s understanding of digestion.  By sharing one of the investigations from this book, you can help students learn that scientists base their explanations on evidence.  After hearing the story, students learn that acid juices in the stomach aid in the digestion of food.

Students learn:

• Science investigations begin with a question.
• The stomach is a bag-like structure that holds food.
• The stomach mixes food up and breaks it down with acid.

Beaumont Gets the Inside Story

Share this amazing story with your students.  They will be fascinated to hear of a man who had

a hole in his side leading straight into his stomach!

William Beaumont (1785-1853) gave scientists lots of evidence about how the stomach worked.  Beaumont was a doctor in the United States.  He had a very unusual patient, a young fur trapper who had been hurt in an accident.  The trapper had a wound in his stomach.  Beaumont took good care of the trapper, and he survived.

The trapper’s wound took a year to heal.  Even when it had finally healed, there was still a small hole leading straight into the trapper’s stomach.  Beaumont could look through the hole and see the inside of the stomach.

Beaumont knew he had a chance to uncover the stomach’s secrets.  He would be able to observe what was happening inside the body.  He could also collect stomach juices for investigations outside the body.

Beaumont asked this question: Do the juices in the stomach act the same way outside the body as they do inside the body. Here is a good stopping point to pause and get opinions from the students.  Do they think the stomach juices will act the same way outside the body?

He investigated by collecting a small amount of juice from the trapper’s stomach. He put the juice and a piece of meat in a test tube and sealed it.  He used a thermometer to find out the temperature inside the trapper’s stomach.  Then he put the test tube in hot water and kept it at the same temperature as the trapper’s stomach.

At the same time, Beaumont put a piece of meat directly into the trapper’s stomach, through the hole.  He tied a string to the meat so he could pull it out again.  The piece of meat in the test tube and the piece of meat tied to the string were exactly the same size.

Beaumont observed the pieces of meat over time.  The acid juices in the stomach soon turned the meat into a soupy liquid.  The juices in the test tube worked more slowly, but they digested the meat just as well as the juices in the stomach did.

Beaumont tried this investigation many times using different kinds of food, and it worked every time.  Here is a table showing how long it took for different kids of foods to be digested.

Beaumont wrote a book about his investigations that led to evidence supporting his claim that stomach’s juices digest food.  Scientists and doctors all over the world read it and agreed with his explanation that it was the stomach’s juices that broke down food.

Opportunities to Reinforce Important Vocabulary

Once you’ve shared this story, you can spend some time reinforcing the vocabulary used to discuss how the scientist studied the stomach.

Introduce investigation.

Write “investigation” on the board.  Say that investigate means to study or try to learn more about something.  Ask the students for the example of the investigation used in the story. [Beaumont observed the inside of a human stomach.]

Introduce claim.

Tell the students that scientists usually begin an investigation with a question.  Say, “In this story, the scientist had the question ‘How does the stomach digest food?'” Write “claim” on the board.  Say, “A claim is the scientists’s idea for an answer to a question.”  Ask the students for the example from the story of the scientist’s claim. [Beaumont thought that the stomach juices could digest food by themselves.]

Review evidence.

Write “evidence” on the board.  Say “When scientists make a claim, they need to investigate to find evidence to support their claim.”  Tell the students that the evidence (or clues) scientists find during an investigation may help them evaluate the claim and decide if it needs to be changed.

Introduce explanation.

Tell the students that a scientist’s claim and evidence together make up his explanation.  Say, “The scientist started with a question he wanted to answer.  He conducted an investigation to collect evidence that could support a claim about how the stomach works.  The claim and evidence formed explanations.”

For more information about the student book Secrets of the Stomach and the Digestion and Body Systems science and literacy unit, visit http://www.scienceandliteracy.org.

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