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No Pain, No Gain


You and Your Students!

Script By

Vicki Cobb, Education World Science Editor


Kids use their tongues to test pain endurance.


Human Body, Senses

Props Required

  • cans of soda/pop (unopened)
  • paper cups
  • a watch with a second hand

Setting the Scene (Background)

Want to capitalize on the popularity of reality shows such as "Fear Factor" and "Survivor"? Set up a pain-endurance competition for your students! This Show-Biz Science experiment will be a great motivator for your kids, and it will create a wonderful "teachable moment" that imparts a good bit of science.

Stage Direction




This is a good activity to do at lunchtime, or at a time when your class is having refreshments. You will want to pay special attention to the timing of the experiment. Soda/pop can go flat pretty quickly -- so you need to do this activity while the soda/pop is at its most fresh and lively. I've found this experiment works best with individual cans of soda that students can pop and pour into cups at a signal. Conduct this experiment as a race with all students starting at precisely the same time.


Act I
Tell students they will be participating in an experiment today. The experiment will test just how tough they are: a pain endurance contest. Tell them you will be giving them a couple of signals.

The First Signal
Provide for each student a paper cup and a can of soda/pop. At a signal, students will pop their soda cans and fill their paper cups. Give the signal!

The Second Signal
Now the contest is ready to begin. Tell students that at the next signal they are to stick their tongues into the soda -- and leave them there for as long as they can! How long can they keep their tongues in the soda?

At the second signal, count off 5-second intervals as students keep their tongues in the soda. Do some students have better pain endurance than others have? Most people can hardly last a minute!

Behind the Scenes

The reason students feel pain when they hold their tongues in the soda is because their saliva changes the carbon dioxide in the bubbles into carbonic acid. Carbonic acid is a weak acid that the body's nerves find irritating. This experiment is stimulating the pain receptors in students' tongues.


Students can usually drink carbonated sodas without feeling pain because they swish around the liquid in their mouths; no one place on their tongues is continually bombarded with bubbles.

How do we know this to be true? Two experiments help us understand why.

  • In one experiment, scientists found that when people were treated with a drug that blocked the acid-producing action of the saliva enzyme, they no longer felt the sting of the bubbles.
  • In another experiment, people drank soda in a high-pressure chamber used by deep-sea divers. There the soda has no bubbles; the carbon dioxide is forced into solution. But the dissolved carbon dioxide still produced the tingling sensation in the mouth.

The End

For additional experiments related to the senses, don't miss Vicki Cobb's Feeling Your Way: Discover Your Sense of Touch (Millbrook Press, Lerner Books). 

Article By Vicki Cobb
Education World®
Copyright © 2005 Education World