Teaching Physics and Creative Problem Solving With Knots

I love paracord. So when I was trying to think up maker programs that can be done inexpensively in only 45 minutes for our maker club at work (I work as a children's librarian) I naturally got to thinking about paracord.

The kids ended up all making an emergency paracord bracelet to take home, but in order to make it “maker” I started with an exercise to show them how paracord works and how different knots should be used for different situations. For further information of the connection between knots and physics, check out this paper by Sir Michael Atiyah.

I was pleasantly surprised with how well this turned out as a program. The kids got really into it, debating which knot they thought would work best, and coming up with testing methods on their own, such as tug-of-war to test the knot’s strength. Definitely maker!

Materials:

paracord rope - one approximately 2 ft long piece per group of kids (we had them into teams of two, but whatever works)
thicker rope (does not matter what kind, but the more slippery the material the better) - one approximately 2 ft long piece per group
a bucket with weights in it (we just used rocks for weights)
large print-outs of how to make different knots: buntline hitch, half hitch, square knot, sheet bend, zeppelin bend

Step 1:

Talk a little bit about what paracord (relatively thin rope with a lot of strength developed for use in parachutes by the military) is and give some examples of situations where one would need such a strong rope and need to know which knots to use (i.e.: parachuting, towing objects, creating a life line to save someone from drowning, etc.)

Step 2:

Have the teams decide amongst themselves which knot is best to tie the two pieces of rope together: square knot (not good for anything with weight to it) vs. sheet bend (ropes of unequal size, therefore the right answer) vs. zeppelin bend (two ropes of same size)

Step 3:

Have the teams decide amongst themselves which knot is best for tying to the bucket: buntline hitch (best) vs. half hitch (too weak)

Step 4:

Let the teams take turns tying one end of their rope to the bucket and hoisting it up by the other end. There should be fairly obvious strain and slippage of the knots if the wrong knot(s) have been used, which you can point out. The team that got the most right wins. In lieu of actual prizes, which we are getting low on, we just let the winning team get first choice of which colour of paracord they wanted to make their bracelet.