HANDS-ON SCIENCE (No Lab Required).

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Author: Unknown

Would a thicker or a thinner rubber band store more energy?

18 oz. empty oatmeal can • 1 sharpened pencil • 2 size-33 rubber bands • 6 metal washers (quarter-size) • 2 cotton swabs • cardboard (28 cm by 38 cm, or 11 in. by 15 in.) • ruler • textbook • tape • 2 size-64 rubber bands

1. Use a sharpened pencil, to carefully make a small hole in the center of the oatmeal container's lid and another in the center of the container's bottom.
2. Loop together two size-33 rubber bands (see illustrations, above).
3. Thread the looped rubber band through the center of 6 metal washers, and tie a knot tightly around the washers. (Make sure that the washers are in the center of the rubber band.)
4. Thread one end of the rubber 'band through the hole in the can's bottom. Then, slip a cotton swab through the rubber band loop poking through the hole. The swab will secure the band.
5. Thread the other end of the rubber band through the hole in the lid. Then, use another cotton swab to secure the loop poking through the hole.
6. Look inside the container to make sure that the rubber bands aren't twisted and that the washers aren't touching the container's sides.
7. Place a textbook flat on a smooth floor, giving yourself a cleared space of 2.5 m (8 ft).
8. Prop one end of a piece of cardboard (28 cm by 38 cm, or 11 in. by 15 in.) onto the book, with the other end on the floor. Tape the cardboard--your ramp--to the textbook.
9. Measure 18 cm (7 in.) up the ramp from the floor and draw a line across the cardboard. This line is the "roller's" starting point.
10. Line up the edge of the "roller" with the line. Release the container down the ramp.
11. Place a piece of tape on the spot where the "roller" stops rolling forward. Let the container roll backwards, and place a piece of tape where it stops again.
12. Measure the distance between the two pieces of tape and record the results. Remove the tape marks.
13. Look inside the container to make sure the rubber bands aren't twisted. Repeat Steps 10 to 12 two more times.
14. Take apart the roller. Then, repeat Steps 2 to 13 using two size-64 rubber bands.

1. Why do you think the roller moved backward?
2. Which rubber bands--size 33 or size 64--sent the roller backward the farthest? Which had the greatest stored energy?
3. What else could you do to increase the roller's stored energy and energy of motion?

PHOTO (COLOR)