Picture of How to make a synthetic muscle

My friend and I are high school seniors who are currently interning with a ninth grade physics teacher at another school as part of our last senior project before we're off to college. These past few weeks we have been prototyping a project that our mentor wants to assign to his future class of freshmen, and so we have built a small, synthetic muscle. We experimented with different types and quantities of materials, but first we'll start off with instructing how to build a simple synthetic muscle.

Here are the supplies we used that you will need in order to create the muscle:

  1. 15-20 test fishing line
  2. Heat gun
  3. Strain,Spring, or Force Gauge
  4. 2 tacks, nails, or screws
  5. A 100 gram weight
  6. Power Drill
  7. Scissors
  8. Two paperclips

It should be noted that while this project can be completed individually, you may need a second person to assist you with some of the steps. Also, we used a force gauge and a classroom wall, but you can similarly use a wood board and a strain or spring if you don't have either of the items we used.

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Step 1: Add tacks/nails/screws

Picture of Add tacks/nails/screws

Insert one of the above tools onto a wall or a board (we used one of the walls of our engineering classroom). Make sure is not completely inserted to the wall, but well enough to remain sturdy and in place if you are using a nail or a screw.

Step 2: Set-up the Force Gauge

Picture of Set-up the Force Gauge

Place the force gauge on the screw with the hook pointing downwards.

Step 3: Place bottom tack/nail/screw

Picture of Place bottom tack/nail/screw

Have the second item ready when synthetic muscle is built. This one can be placed about a foot away from the top nail and will be connected to paperclip attached to the bottom end of the muscle later on.

Step 4: Cut some fishing line

Picture of Cut some fishing line

Measure and cut 14 inches of fishing line. The intended goal is to have at least a foot of fishing line because you will need to tie both ends of the fishing line to the paper clips, and that will require a bit more fishing line. The muscle will be approximately 20% of the original length because it will shrink as it coils.

Nice demonstration of the contractile property of many plastics when heated. How much force did you achieve and how many cycles would it go through?


It sure would neat to see a video of it in action.