As the World Turns: The Coriolis Effect

Purpose: To learn how the rotation of the Earth causes global wind patterns

Materials

• compass
• unsharpened pencil
• transparency or white paper
• erasable marker
• tape
• scissors
• hole puncher

Procedure

1. Using your compass, draw a 17-cm diameter circle on the transparency or white paper.
2. Mark the center of the circle with a small dot.
3. Cut out the circle, and using the hole puncher, punch a hole at the center mark.
4. Place the pencil through the punched hole with the eraser side at the top. Tape the pencil in place so that it is directly next to the bottom of the unsharpened side of the pencil and almost flat with the surface.
5. Have your partner spin the pencil so that the disk twirls.
6. While the disk is spinning, use a marker to try to draw a straight line from the center of the disk to the outer edge.
7. Have your partner stop spinning the disk and observe.

Conclusion

1. Was the line straight? Why or why not?
2. Explain how this effect is similar to the global wind patterns?