roller coaster goes upside-down.
Let's test out this force!
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roller coaster goes upside-down. Let's test out this force! |
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string |
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a ballpoint pen or pencil |
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water |
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a paper cup (7- or 8-ounce cups work best) |
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First, make your own min-bucket. With the pen, poke a hole near the rim of the cup. Then poke one directly across from it on the other side of the cup. |
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Cut 2 pieces of string about 2 feet (60 cm) long each. Attach each string to a side of the cup by looping it through the hole and tying a knot. |
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Now fill your
"bucket" halfway with water. Take the ends of the strings in your hand
and whip the bucket around in a circle over your head. Be sure to stand
away from your friends and any breakable objects.
(You may want to sway the bucket back and forth a bit before you make a full circle.) |
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Try to repeat the experiment, but this time fill the cup 3/4 of the way with water. (You can also try to do it with a penny in the cup instead of water.) |
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How is this like a roller coaster going upside down? Tell us what you think! |
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Sir Isaac Newton,
a scientist who lived 300 years ago, made observations that explain the
behavior of moving objects - like kids on roller coasters.
One of the important things he noticed is that "a body in motion will move in a straight line unless acted upon by an outside force." When a roller coaster launches into a loop, you might wonder why you don't fall out. Actually, what you should wonder is why you don't go shooting into the sky! Your body tries to "remain in motion" - in a straight line toward the sky! Luckily, you're acted on "by an outside force" - coming from the seat and the floor of the car. They stop you so that you don't go flying! |
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