I used my muscles a lot this weekend, hauling heavy equipment cases through airports, to TV stations for interviews, for outreach shows and to the power plant. That got me thinking about an experiment that involved muscles. We have so many different muscles, for doing so many different things. Finally I decided on a group of muscles that are very small and often overlooked.
For this experiment, you will need:
For this experiment, we are going to give you goosebumps. You may also know them as chill bumps, because they often appear when you are cold. That is one way we can produce them. Put some water into a bowl and add several ice cubes. Swirl it around to make the water very cold. Now comes the fun part. You are going to get your friend to dribble some of the ice water down the back of your neck. As you are waiting for the ice water, watch the skin on your arms. As the ice water hits your neck, you should see tiny bumps appear on your arms. These are goosebumps.
Another way to see them is to have someone tickle the back of your neck very lightly with a feather or a strip of tissue paper. Have them just barely touch the feather to the base of your neck and gently stroke it upwards. This should send chills down your back and produce a nice crop of goosebumps.
OK, now that we have you all bumpy, lets think for a minute about what is happening. You have about 5 million hairs on your skin, and each of them has a tiny muscle attached to it. These are not voluntary muscles, which means that you can't wiggle your hair whenever you want. (Wouldn't that be neat!) Instead, the muscles tighten when you get cold, are scared or angry, or when something tickles the back of your neck. When these muscles tighten, they cause your hair to stand up. As the muscle contracts, it gets shorter and thicker, producing a bump on your skin.
People are not the only ones that have these muscles. If you have ever seen a cat that is angry or frightened, you probably saw that it puffed up to almost twice its normal size. This is especially visible on the tail, which may look more like a bottle brush. Dogs also bristle their hair, especially the hair around their neck and shoulders. This makes them look bigger and more threatening to an enemy.
Even if you don't get enough reaction to get large goosebumps, you should still be able to feel the strange, shivery sensation as these tiny muscles flex and move the hairs on your arms. Of course, if you want to keep trying, I am sure that your friend would be glad to pour lots of cold water down your neck.
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