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Sunday, December 02, 2012

10 Famous Thought Experiments That Just Boggle Your Mind Part 6

Read Part 5: The Ship of Theseus

5. Galileo's Gravity Experiment

In order to refute Aristotle’s claim that the speed of a falling object is dictated by its mass, Galileo devised a simple thought experiment:

According to Aristotelian logic, if a light object and a heavy object were tied together and dropped off a tower, then the heavier object would fall faster, and the rope between the two would become taut. This would allow the lighter object to create drag and slow the heavy one down. But Galileo reasoned that once this occurs, the weight of the two objects together should be heavier than the weight of either one by itself, therefore making the system as a whole fall faster. This contradiction proved that Aristotle’s hypothesis was wrong.

One of the most famous stories about Galileo is that he once dropped two metal balls off the Leaning Tower of Pisa to prove that heavier objects do not fall faster than lighter ones. In actuality, this story is probably just a legend. However an astronaut did perform this famous Galileo test with a hammer and a feather in vacuum with low gravity on the surface of the moon (see video below).

So what can I learn from this thought experiment? As a Computer Science researcher, many times it is easier for me to just sit down and code up experiments. But sometimes it might be a good idea to stand up and then write down the math formulations on the whiteboard. Simplifying the math calculations or jog down some proofs can actually dramatically reduce the amount of coding I have to do and also improve the performance of my algorithms. Of course, if I could do all these in my head it would be wonderful, but I am no Galileo, and I also have severe short-term memory deficit -- a strong sign and that I am almost ready to graduate!

Read part 7: Monkeys and Typewriters

Video of the Day:

Air Swimmers -- a fun "robot" toy for parties! You can get them here.