Melissa called the display "The Helping Hand" and made a display showing different functions of the hand, including how it is used in braille and American Sign Language.
For Melissa's investigation, she put together a shoe box full of ten items from around the house and backyard. (pinecone, bouncy ball, stick, rock, toy rubber mouse, rubber popper, crayon, eraser, rubber band, and a leaf). She then covered them with a cloth, and tested ten different people, asking them to identify the items using only their sense of touch. Her hypothesis, based on the number of touch receptors in the fingers, was that people could guess all the items correctly 90% of the time, which would demonstrate how sensitive and important the hand is. At the conclusion of her investigation, she found that 6 out of the 10 people actually were able to guess all items correctly 100%. This showed that the hand was even better than she thought it would be!
Some extras Melissa made for her display included hand shaped sugar cookies to share, as well as a model robotic hand that we learned about from Supercharged Science.
Here is the background paper that Melissa wrote about the hand:
Isaiah 41:13 “For I the LORD thy God will hold thy right hand, saying unto thee, Fear not; I will help thee.”
This verse shows that hands are strong enough to hold you up. Of course, you use other muscles as well, but you cannot use your arm muscles to hold onto something or someone - you have to use your hand.
From your wrist to your finger tips there are twenty-seven muscles in just that one area! Although the hand moves from the forearm muscles, the fingers move from the hand muscles. It is also said that fingers on just one hand will be flexed and extended about twenty-five million times over the course of one’s lifetime.
There are two different types of gripping: power grip and precision grip. The power grip is used for carrying heavy bags or holding onto a handle, for example, you grab a grocery bag and you hold the handle of the bag in the palm of your hand. The flexor tendon then pulls the fingers and thumb to tightly close around the object. The precision grip, on the other hand, (not literally) is used for handling and moving an object, such as when you are writing, sewing, or drawing. The thumb and index finger work like forceps.
The reason why your fingers are the most sensitive in your entire body,(unless you’ve burned them too many times), is because there are seventeen-thousand touch receptors and nerves in them. They pass on sensations of pressure, movement, and vibration.
Without your hand you would not be able to eat, type, sew, or do anything that you enjoy. God knew all of that before scientists even discovered how the hand worked inside. The hand shows how amazing and wonderful God really is.
Since we are studying Apologia Anatomy & Physiology this year, this science project was merely an extension of our studies. It was fun to put together, and we learned quite a bit by doing it!
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