You and Your Students!
Vicki Cobb, Education World Science Editor
Teach about properties by passing a coin through a solid.
Setting the Scene (Background)
Do you silently moan and groan when you have to teach properties of matter? Generalizations that seem unrelated to daily life (state of matter, density, color, and so on) are boring to learn about and are boring to teach. But a property of a particular kind of matter becomes fascinating when it is unusual and allows you to do something unexpected or magical
Everyone knows a solid can't pass through a solid. But, with a little preparation, you can make a quarter appear to pass through a solid latex membrane. Suddenly, properties of matter become a topic worthy of attention!
This is close-up magic that requires you to prepare ahead of time without any students watching. This demonstration is most effective when done with a small group standing around you. The kids will want to know how you did what you are about to do; letting them in on the secret is where the lesson becomes powerful.
Act I: The Set-Up
Act II: The Performance
Now invite your audience over to watch. Claim that you can make the coin pass through the latex without making a hole in the latex. Give the coin a tap from above. It will drop like a shot into the jar, leaving the latex undamaged.
Behind the Scenes
The property of latex that allows you to do this trick is its elasticity. Latex is a material that has a memory. You can bend it or stretch it, but when the distorting force is removed, the rubber returns to its original shape. You're exploiting this property twice in this trick.
Materials engineers are always looking for applications that take advantage of a material's unusual properties.
Article By Vicki Cobb
Copyright © 2005 Education World