Exponential Growth & Paper Folding

Humans are terrible at understanding exponential changes. As an exercise to demonstrate this, I asked the kids in my group to start folding a piece of paper on itself. I asked them how thick would it become if they folded it more than 40 times. Everyone showed me with their hands on how thick they think it would become.

As an assignment, I told them to solve the question at home and show me how thick the folded paper would become if it was folded 42 times. We assumed the sheet of paper was 0.1 mm thick.

This tied in well with the STEM stuff they were doing at the time, learning measument units and conversions.

The following week I got many funny looks and kids thinking they got it all wrong when their calculations showed them that the sheet of paper would be more than 400,000 km in thickness. Keep in mind the moon is on average 384,000 km away from us.

We then spent some time going over the linear growth and exponential growth with charts, it seemed to work well. We will re-visit this topic again in the future.

Somebody on the internet did all the hard work of explaining this better, so here it goes.

http://wwvv.codersrevolution.com/blog/will-a-piece-of-paper-folded-42-times-reach-the-moon