Find a smooth, cylindrical support column, such as those used to support open-air roofs for breezeways and outdoor hallways (check your local public school or local church). Wind a length of rope one time around the column, and pull on one end while three friends pull on the other in a tug-of-war fashion.
Experiment with the number of friends and the number of winds around the column. Can you hold your end with just two fingers against an entire team of football players? You bet!
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Here's what you need:
- nylon long rope (10 feet or longer)
- column or pillar (as talked about in the video)
- at least two people, but more is better
What’s going on? This is a great example of what “exponential growth” truly means. There is friction between the rope and the support column – you can feel it as you tug on the rope. With every additional turn around the pole, the amount of friction increases (exponentially grows), until it skyrockets so much the rope feels as if it’s welded to the pole.
Download Student Worksheet & Exercises
Einstein himself stated that “exponential growth” was the eighth wonder of the world!
Exercises
- How much money would you earn on Day 20 if I gave you one penny on Day 1, and doubled it every day after so Day 2 you received 2 pennies, and Day 3 you got 4 pennies?
- Why do you think this experiment with friction works? Does it work with a flat surface the same way as a curved surface?
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