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Student Guide: Ow, My Tummy Hurts! The Biology and Chemistry of Gas Relief

Downloadable and printable Student Guide PDF.
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Summary

Have you ever felt bloated, or had your stomach ache and feel blown up like a balloon? It could be because too much gas was trapped in your digestive system. How do some drugs relieve trapped gas, and help make your stomach ache go away? Find out using soapy water and simethicone, a drug that helps get rid of gas trapped in your digestive system and helps you not feel bloated anymore.

Useful Vocabulary

  • Gastrointestinal tract: Also known as the digestive system, this includes your stomach, intestines, and other organs that work together to break down food you eat so your body can use it.
  • Gastrointestinal gas: Many tiny, microscopic organisms live in your gastrointestinal tract and help you break down food. They make gas when they do this, and gas bubbles can get trapped within broken-down food.
  • Flatulent: When you have too many gas bubbles trapped in your gastrointestinal tract.
  • Surface tension: How a liquid, like water, is held together at its surface, where the liquid and air meet. Surface tension is what enables a single drop of water to sit like a small bead on a counter top. The surface tension of water is large enough that it is difficult to make bubbles using plain water, but if you add soap to water you get lots of bubbles. This is because bubbles need just the right amount of surface tension to form; plain water has too much surface tension, and soap decreases it so that bubbles can form.
  • Simethicone: A drug that helps relieve flatulence by making gas leave your body more quickly. Simethicone does this by decreasing surface tension a lot — more than soap. What do you think this decrease in surface tension does to the trapped gas bubbles?

Materials

To do this activity you will need:

  • Jar, drinking glass, or vase with crushed simethicone tablets (1)
  • Empty jar, drinking glass, or vase (1)
  • Enough water to fill both jars
  • Liquid dishwashing detergent (10 drops)
  • Straws (2)
  • Timer or clock that shows seconds (1)

Directions

  1. Fill both jars halfway with water. How does the water look in each jar? Keep track of which jar has the simethicone and which does not.
Classroom Activity Gas Simethicone picture of crushed simethicone tablets in a jar with water
Figure 1. Fill each jar halfway with water.
  1. Add five drops of liquid dishwashing detergent to each jar.
  2. Fill both jars with water until they are filled to about an inch from the top of the jar.
Classroom Activity Gas Simethicone picture of crushed simethicone tablets in a full jar with water
Figure 2. After adding detergent to each jar, fill them almost full with water.
  1. Put a clean straw into each jar.
Classroom Activity Gas Simethicone picture of jars of water with straws
Figure 3. Put a straw in each jar.
  1. Carefully mix each jar with its straw. How does the water look in each jar after mixing? Do you see any bubbles?
  2. In the jar that does not have simethicone, slowly blow through the straw for ten seconds. What happens to the water in the jar? Do bubbles come out of the straw? Do the bubbles form a layer on top of the water?
  3. In the jar that does have simethicone, slowly blow through the straw for ten seconds. Try to blow just as hard as you did with the other jar. What happens to the water in the jar? Do bubbles come out of the straw? Do the bubbles form a layer on top of the water?
  4. What do your observations tell you about how the drug simethicone helps get rid of gas trapped in your gastrointestinal tract?