There’s an old gag that challenges someone to fold a dollar bill in half eight times. If they can do it, they get to keep it.
The trick is that it gets so thick, so fast, that six folds are usually the limit.
You can try it yourself with a dollar bill, a sheet of printer paper, or even a double sheet of newspaper! Fold it in half, turn it sideways, and fold it again.
In each case, you’ll find seven times is about as far as you can get by hand without hurting yourself.
Of course, if you use a huge sheet of very thin paper, you can get a few more folds out of it. The current record is 12 folds using long tissue paper.
But the real point behind this trick is showing how doubling something again and again can lead to very big numbers very quickly.
You don’t have to use the word exponential yet, if your young scientist is working on addition right now, but even the youngest can see what’s happening.
Fold in half once, you have two layers.
Fold in half again and you have four layers.
One more time and suddenly you have eight layers! It does go quick.
Then 16, 32, and maybe 64 layers thick in only seven folds. Phew!
I remember a brain-teaser that I saw way back when I was a young scientist of maybe twelve years. It went something like this…
A college professor, who was very rich, had fallen into a river and was drowning. Two students jumped in after him and, working together, they pulled him to safety.
The professor was very grateful and offered each of the men their choice of a reward.
He would give them a check for one million dollars right now or give them one penny now and double that amount each day for 30 days.
One student spoke up immediately and said, “You are very generous, sir. I will take the one million dollars now, please.”
As the professor wrote out a soggy check, the other student had time to think a bit.
He said, “Sir, you are very generous to offer a penny doubled each day for a month and I will choose that.”
The professor smiled and said, “My boy, you are very bright and will go far in this world. Here is your penny. See me tomorrow for two.”
…..
If you’d enjoy using a calculator to work it out yourself, you’ll be amazed how much it adds up to.
If you’re on the go and want to see it done for you, look here.
In any event, grab a sheet of paper and see how many times you can fold it in half!
