Kind: captions
Language: en
Okay, so we're at the University of
Sydney to experiment with Dr. Phil's
dead bird.
He's a famous scientist, this guy. He
helped us out back in uh the 16th
century.
It was a 17th century, isn't it?
17th century. 1600 1600s. Thank you.
Galileo
was uh was discussing gravity. Um a lot
of people, of course, thought that
different things fell at different
rates, but Galileo said, "No, no, no,
no, no. Gravity is the same for all
bodies, no matter how heavy or light.
Um, so we're going to prove that right
now, aren't we?
Okay, let's give it a shot.
Yeah. So, so, um, young, uh, Galileo
here, he's going to lend us a feather.
Feather's very light, but it's still
going to fall at the same acceleration
as this coin made of metal.
So, you're telling me they're going to
accelerate together towards the ground?
That's right.
And you know, I don't believe you. I've
How could you? I'm a scientist. All
right.
So, let's do the experiment and let's
see what happens.
Yeah. One, two, three.
That's actually going upwards.
[laughter]
All right. So, what was happening there?
Obviously, they didn't accelerate down
at the same rate.
Well, maybe there's some other factors
going on here. What do you reckon?
Maybe. Or maybe it's uh it's the dead
bird's fault.
Maybe it's the dead bird's fault. He was
blowing up. Blowing. It's air. Maybe we
need to get rid of the air. What do you
reckon?
Okay, let's get rid of the air and see
what happens.
As it happens, we've got a vacuum pump
here.
Okay.
So, if we put this feather
and this
coin
in here,
seal it up.
Then we can pump all the air out.
All right, let's do it. So, we're
sucking all the air out now. It's coming
out of the pipe, down the tube, out of
here, through the air. So, uh, we're
really getting rid of most of the air,
so there'll be no wind resistance as the
feather falls this time. It's kind of
like a vacuum cleaner, but it really
sucks.
[laughter]
All right. So, uh, let's try it out.
Let's see if, uh, they accelerate with
the same rate. Now,
you ready for this?
Yep.
One, two, three.
Wow, they did fall at the same rate.
[laughter]