Gravity


< Back to our Gravity Meeting	This is how we made a straw balance at the end of our fingers. First we needed to move the balancing point to one end of the straw, instead of the middle. You can do it too.
You Will Need:	° plastic drinking straw ° pipe cleaner (or stiff wire) ° metal washer (or a piece of clay)
	Here's what you do:
	1) Put one end of the pipe cleaner through the washer and twist it around a couple of times, like this:
	2) Take the other end of the pipe cleaner and wrap it tightly around one end of the straw. Attach it as close to the end as you can (but leave a little room for your finger).
	Now for the tricky part.	Look at the picture for help.
	3) Carefully bend the pipe cleaner DOWN and also AWAY from the end of the straw, so the metal washer sticks out PAST THE END OF THE STRAW.

		If you put your finger under the middle of the straw, you can see that you changed the balancing point of the straw.
	Now if you put your finger at the end of the straw you can make it balance on the tip of your finger. It looks like it should fall but it doesn't!

You might have to slide the pipe cleaner a little bit forward or a little bit backward.	You might need to bend it a little more if it doesn't work the first time. Play with it a little until you get it just right.
	Try balancing the straw on something other than your finger. See if you can balance it on the eraser end of a pencil.

If you want, you could try different weights, instead of the metal washer. You could use a ball of clay or a cork instead. You don't have to use a straw either. You might want to try using a ruler or a stick, but then you will need a heavier weight.

USE YOUR

IMAGINATION

To make the balancing tricks work, you have to move the weight around. You have to find a place where the weight is the same on both sides. Most people call this middle place the center of gravity.			You can find out more about gravity in our Curiosity Crew Library.

			Back to our Gravity Meeting

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