How Do Muscles Work?

how do muscles work

Nicholas has been learning about the muscles in his body.   He’s learned about the tree types of muscles – smooth, skeletal, and cardiac.   He is working on learning the names and locations of some of the major skeletal muscles in his body.

How Do Muscles Work?

We have read about how a muscle works through contracting and extending but there is nothing like a hands-on project to bring learning to life.

So my son made a model of his arm, complete with bicep and tricep muscles, so he could learn first hand how these muscles work.

He first had to build the bones that the muscles attach to.   For this, he used a cardboard tube from a roll of wrapping paper and cut out a piece the length of his humerus bone.

Then he measured his forearm and cut out another piece of cardboard to match. He cut this forearm piece in half lengthwise and taped them together to form 2 more narrow bones – his radius and ulna bones.

making bones for muscle model

He labeled his bone model carefully. He straightened out a paper clip and punched it through the ends of his pieces of bones to connect them, just like a joint would do. He attached the forearm bones together with a rubber band in place of a wrist.

making a muscle model

Make a Muscle

To make the muscles for his model, Nicholas used two long red balloons – the skinny ones you use to make balloon animals.   He blew them up   just slightly and pressed the air to the center of the balloon, leaving lots of unused balloon on either end.   Next he tied each of the ends of the balloons to his bones to form the bicep and tricep muscles of his model.

Now he has his own model of a muscle that he can use to demonstrate how the bicep muscle extends when the arm is straight and how the muscle contracts when the forearm is pulled up.

muscle model collage

The human body is a fascinating wonder of science.   The Quirky Mommas love using fun hands-on projects to teach their kids about their own bodies.   Here are just a few of their ideas:


  1. Very intellegent

  2. nice bt i want a modelss

  3. Great idea ……. I think this will help kids to understand the actual functioning of a muscle.

  4. Nothing teaches children science better than creating hands on models and experiments! Thank you so much for this post!

  5. Yesterday, while I was at work, my cousin stole my iphone and
    tested to see if it can survive a 25 foot drop, just so she can be a youtube sensation.
    My iPad is now broken and she has 83 views.
    I know this is totally off topic but I had to share it with someone!

  6. Hey! Quick question that’s totally off topic. Do you know how to make your site mobile friendly? My blog looks weird when browsing from my iphone. I’m trying to find a template or plugin that might be able to correct this
    problem. If you have any recommendations, please share.

  7. Katherine says:

    Okay, so I tried this for a science co-op I’m in. I thought I should test it out before we have the kiddos do it, and I’m glad I did. This is much harder than it looks. Be sure, if you do this, to have a pump for the balloon. Also, watch out for the ends of the paperclip. I had to turn mine inward so it wouldn’t poke the balloon…again. Oh and by the way, this project only produces the flexing of the bicep muscle, not both bicep and tricep. For some reason I though both muscles were suppose to move. Now I see the tricep didn’t move, it’s just the picture was taken at a closer angle.

  8. Thanks for the notes.I will try it myself first before doing it with the kids too.

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