Surprising, Quick and Easy Science Trick
July 07, 2011
I was always one of those teachers who hated to see my students act bored. My goal was to have many quick lessons with tons of transitions from one activity to another. On this one particular day, my students looked rather lethargic sitting in their seats. As an effort to intrigue them, I recalled a quick and interesting science fact that could be turned into a mini activity.
One person is holding a dollar bill (or any amount) with two fingers upright in the air. Smooth the bill so there are no wrinkles.
The goal is for the other person to catch the dollar bill between two fingers before the bill falls past. The person to catch the bill must have two fingers open and ready to pinch the bill. They should be positioned in the middle of the bill on George Washington's face. If the fingers are positioned lower, then it changes the outcome. A crinkled bill will also change the outcome.
Back in 1997 was my first year teaching. I was so confident that nobody would catch the bill that I offered a $20 reward. Most of my students attempted it many times but to no avail. If the catcher honestly reacts to the person letting go of the bill, it is impossible to catch. You see, the human reaction time is slower than the rate it takes the bill to fall through the air. In my 15 years working with students, I’ve only had two students catch the bill. Unfortunately, one of those times was the time I offered a $20 reward. Don’t remember my student’s name but I know he was a basketball player. He reacted before I let go of the bill and nonetheless was able to catch it. I’ve learned my lesson and now only offer a $1 reward.
My daughters got a kick out of trying this. We discussed the meaning of human reaction time and the factors that affect the speed at which things travel in air. Our conversation went off on a tangent to paper airplanes. We discussed how the long skinny paper airplanes will travel faster than the short fat ones and the reason for the differences. Since we were discussing a topic that was important to them (paper airplanes) they didn’t mind all the science talk.