I’ve been looking for something to do with Logan to start explaining how things work. I found this on the web:
We traced an adult sized hand on cardboard and carefully cut it out:
We glued the bendable straws on each finger, so that the bendy part was on the hand and the long part of the straw was on the fingers. We trimmed the edges of the straw to align with the edge of the fingers.
We took our pencil and marked on the fingers of the cardboard hand the location of the joints and knuckles from the real-life hand. Then we took the utility knife and carefully scored the back side of the hand on those lines, so that the fingers would curl and bend properly.
Using our pencil marks as a guide, we carefully sliced a section of the straw off (at 45 degree angles) where the joints are located. This helps the ‘fingers’ to bend properly as well.
When we are done with all the joint cuts, it looks like this:
We took string and ran it through each straw, leaving a long tail out both the top and bottom of the straw. We cut the rubber bands so that they would be a long strip instead of a circle. At the top of each finger, we tied the string and rubber band ends together in a small knot.
Turning the hand over, and with fingers straightened out and laid flat, we hot glued the loose ends of the rubber band down to the back of the hand. The glue should only be right at the end of the rubber band. The rest of it needs to stay loose so that it can freely move and guide the fingers. The rubber bands help the fingers to return to their natural state after being curled up.
Once the hand was completed, we had lots of opportunity to ‘play’ with it and see how the tendons in a hand function, by pulling downward on the strings.
One of the favorite things to do with the hand was to make sign language letters and spell out words and phrases….or to say “I love you”!
This was a great project and we were very happy with the outcome. Everyone who has seen it is fascinated by it, and it clearly demonstrates the movements of a hand. I highly recommend this project!
Source: “Be The One” : Apologia Anatomy & Physiology Unit Three: Build A Model Robotic Hand
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