Thursday, July 6, 2017

Galileo Just Needed a Vacuum Chamber - A Brigid Guest Post

No writings today - it was an exceptionally long work day.  But I'm sharing a video for you fellow science geeks.

Galileo's Hypothesis.

From the earliest times, gravity meant the tendency of most bodies to fall to earth. In contrast, things that leaped upwards, like flames of fire, were said to have “levity”. Aristotle was the first writer to attempt a quantitative description of falling motion: he wrote that an object fell at a constant speed, attained shortly after being released, and heavier things fell faster in proportion to their mass. Of course this is nonsense, but in his defense, falling motion is pretty fast it’s hard to see the speed variation when you drop something to the ground.

Aristotle most likely observed the slower motion of things falling through water, where buoyancy and fluid resistance dominate, and assumed that to be a slowed-down version of falling through air which it isn’t.

Galileo was the first to get it right. (True, others had improved on Aristotle, but Galileo was the first to get the big picture.)

He realized that a falling body picked up speed at a constant rate in other words, it had constant acceleration (as he termed it, the word means “addition of speed” in Italian). He also made the crucial observation that, if air resistance and buoyancy can be neglected, all bodies fall with the same acceleration, bodies of different weights dropped together reach the ground at the same time. This was a revolutionary idea as was his assertion that it should be checked by experiment rather than by the traditional method of trying to decipher what ancient authorities might have meant.  He mentioned that a cannonball and a feather, if dropped from the same height will touch. With current technology, it has been experimentally demonstrated.

Turn your sound up, click on the video to view and  watch full screen to view. - Brigid

1 comment:

SiGraybeard said...

They make it look like the guys in the control room were genuinely surprised at the results. Sorry, but that can't be.

Not that it wouldn't be fun to do, but surprised? ... No.

To me, the fun fact is that Galileo did his initial experiments on an inclined plane, and timed the experiment using his pulse. That's a completely unemotional guy!