Can something fall faster than gravity? Breakthroughs can come from simple ideas
Many people are familiar with this classic science question: will a tennis ball, with a small mass, reach the ground later than a bowling ball? The answer to this thought experiment which was once famously conducted by Galileo off of the Tower of Pisa is: No.
The laws of physics dictate that gravity accelerates falling objects at the same rate, irrespective of their mass. On Earth, countless applications of physics depend on the fact that gravity stays constant for most (not all) falling objects.
One study from Cornell University and its research of the properties of chains stand in the way of me using the word “all.”
They first looked at the way a normal chain with oval loops linked together falls. In the case of a chain falling onto a table, usually what we imagine is that the part that hits the table doesn’t have any effect on the section of the chain above it that is still falling. And by recording two looped chains falling, one on a table and the other to the floor, that is exactly what they observed. The last link that connects the parts at rest and in free fall is disconnected, which means that it doesn’t transfer any force nor change how fast the chain falls.
But what the researchers realized is that, in principle, the last link could put a force on the section above it. They achieved this effect by building a chain looking more like a ladder with two ropes strung through the ends of several slanted wooden dowels (see image).
The way it works is that, as the lower end of the dowel hits the table, it pivots and speeds up the other end thereby pulling on the dowel above it. It speeds up for the same reason that a person roller skating will turn quickly if they grab onto a stationary pole. The interesting result is that the chain actually pulls itself toward the ground faster than the normal force of gravity. What? Defying gravity?!?
I was drawn to this research because, as far as I know, this phenomenon has only been described in this study which was done in 2011. And from watching their video of the chains, it’s clear that it works.
By looking at something as unassuming as a chain, these researchers were able to come up with a startling result. Evidently, it shows that breakthroughs can come from looking at simple ideas.
To watch this amazing experiment, visit: http://ruina.tam.cornell.edu/research/topics/fallingchains/Falling_Chain_experiments.html
Shion Britten is a senior at Southridge High School and enjoys playing the trumpet, baseball & hiking. To prepare for college, this will be Shion’s last teen essay. Good luck Shion!