Duration: 30 minutes
Notes / Activity
Discrepant events: Rolling can which rolls back
PS3.B: Energy is present whenever there are moving objects, sound, light, or heat. When objects collide, energy can be transferred from one object to another, thereby changing their motion. In such collisions, some energy is typically also transferred to the surrounding air; as a result, the air gets heated and sound is produced. (4-PS3-2),(4-PS3-3)
By the end of this lesson, the student should able to:
Prepare before lesson:
Coffee tin / plastic container
Drill or pinch device
2 elastic bands
Paper clip
Tape
Cotton thread / string
Small weigh (e.g. washer)
Prepare the tin by doing the following:
Information for teacher:
Roll the tin away from you: This should “wind up” the elastic, causing the can to roll back again. This can be quite mystifying to those seeing it for the first time.The weight in the tin can hang down as the tin rolls in one direction. The kinetic energy of the rolling can will be stored as potential energy in the tightly twisted rubber band - some will be lost as heat and sound.
Coffee tin / plastic container
Drill or pinch device
2 elastic bands
Paper clip
Tape
Cotton thread / string
Small weigh (e.g. washer)
What is energy?
Elicit from students:
Can you name some forms of energy?
Is there any form of energy when the can is rolling? Why or why not? What are they?