Today's Classroom Activities :

Learing About Friction

Friction Studies
Science With the class, set up a hypothesis about friction and moving objects. Then ask your students to plan the following scientific experiment to test your hypothesis. First, roll a ball down a specified length of tiled floor. Roll the ball down the same distance on a carpeted floor and again on the grass. What differences were observed? What were the conclusions drawn?

Using just a shoe, a protractor and a large board, students can get an inside look at the mechanics of friction. Read how in John Cowens' article Get A Grip!.

Musical Wine Glass
Fill a thin-walled wine glass halfway with water. Dip your cleansed index finger into the water and rub slowly around the rim of the glass. With a little practice, a lovely, resonating note is produced.

Explanation:
As your index finger rubs over the glass, friction is produced. Soon afterwards, the glass starts to vibrate and produces a sound. (Watch the water as you rub the rim in a circular motion. The vibrations can be seen clearly on the water surface.) The pitch of the sound depends on the amount of water in the glass.

Repeat this experiment but use three or four thin-walled wine glasses with different amounts of water in each glass. Can you turn the sounds into a pleasing chord or harmony?