Introduction

And now, for your post-Thanksgiving dinner entertainment!

Objectives

To learn about friction, inertia, and Newton’s First Law of Motion

Materials

• 12 coins (nickels work well)
•  Butter knife or flat rubber spatula
• Table/flat surface

Procedure

Stack the 12 nickels on a table. Try to get the bottom coin out of the stack without making the tower of coins topple over by using the dinner fork or spatula. After practicing this to learn how much force is necessary, you should be able to push the bottom nickel out without making the money tower collapse!

Conclusion

The stack of nickels is at rest, or not moving. As Newton’s First Law of Motion states, an object at rest will remain at rest unless acted upon by a force. To make the bottom coin move, it is necessary to push it quickly to overcome friction. If you push the bottom nickel slowly, friction helps pull the stack long with it by “sticking” the coins together. However, if you push quickly, the coins still rub, but the friction force doesn’t have time to get the stack moving. You may have to practice but the results are worth it!