This week, a simple demonstration of how the muscles in our hands are put together.
You will need
A matchstick or toothpick
A hand. The one at the end of your arm should do.
What to do
Hold your hand flat, in mid-air.
Lift up your middle finger.
Lay the matchstick between the nails of your second and fourth finger.
Holding your fingers straight, try to break the matchstick by pressing down with your middle finger while pressing up with your second and fourth fingers.
Can you break the matchstick?
What's happening?
Most people find it very difficult or even impossible to break the matchstick. Its all to do with how are hands are put together.
Our hands have evolved to grip things. We have lots of muscles on the inside of our hands that curl our finger around and grab things. On the other hand (so to speak), the muscles for straightening our fingers are not nearly as strong.
When you tried to break the matchstick, your middle finger was pushing down, using the muscles you normally use for curling your finger. However, you were also pushing up with your second and fourth fingers. This uses the muscles you normally use for straightening your fingers. Since these muscles aren't strong, it's almost impossible to push up hard enough to break the matchstick.
If you try placing your hand on a table, you'll find it's much easier to break the matchstick, because you can rest your fingers on the table instead of having to push up with them.
Place the matchstick between the nails of your second and fourth fingers.
Press down with your middle finger while pushing up with the fingers on either side.
