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Gravity, it's one of those weird things in life.
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We all kind of know what it is
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but we kind of don't as well.
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And there's something I've always
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found really hard to believe.
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400 years ago, Galileo said, "If you drop
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"two things of different weights, they'll both
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"hit the ground at the same time."
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Which doesn't seem to make any sense
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because surely the heavy thing would hit the ground first.
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So if I weigh 73 kgs and this orange weighs 100 grams
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and I jump out of a plane with the orange,
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which one is gonna hit the ground first?
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In this episode I thoroughly test Galileo's theory
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by using a roller coaster to experience gravity
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on another planet.
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Jeez.
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(engine whirring)
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Achieve weightlessness without going into space
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and then I jump out of a plane with an orange.
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(screams)
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I've always been fascinated with how the world works
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and I've got lots of questions about why things happen.
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To find out the answers, I'm gonna blow stuff up.
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I'm pretty sure if Galileo was alive today
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that he would've wanted to have jumped out of a plane
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to test his idea as well.
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We tend to think of gravity like this.
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(egg splattering)
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Stuff falling.
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But the law of gravity is way, way weirder
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than you could ever imagine.
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So I drop this egg and it falls to the earth, right?
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Well, not quite, something else happens.
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The law of gravity says that both the egg
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and the earth are attracted to each other.
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That's how gravity works.
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Everything is attracted to everything else.
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So a large bridge seemed the best place to experience this.
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You know that expression, "putting on a brave face"?
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Well that's mine, right there.
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(Nigel grunting)
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People think that stuff falls, stuff like eggs
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and in this situation me, but the law of gravity
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combined with Newton's third law says that something
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way, way weirder is happening.
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I might be falling but the earth
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is also falling towards me.
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(Nigel laughing)
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To be fair though, the earth does have
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80 billion trillion times more mass than I do.
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So it does most of the attracting
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and I do most of the falling.
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But in a very tiny, tiny way,
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the earth also moves towards me.
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So if this orange and this apple
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were floating in space, then gravity would slowly
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start to draw them together.
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And as they got closer together, the strength
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of gravity would increase until after
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about 84.5 hours they'd meet.
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The thing which complicates everything is air.
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We all know, that if you drop a feather and a coin,
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the coin's gonna hit the ground first.
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That's true, but it's not the whole story
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which is why I'm dropping the coin
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and the feather in a vacuum chamber.
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Galileo was a really clever bloke.
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He worked out two objects of different masses
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will fall at the same rate in a vacuum.
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With the air pumped out of our vacuum chamber,
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the feather and the coin land at exactly the same time.
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Whereas when the chamber was filled with air,
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the coin landed first.
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In what historians think was only
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ever a thought experiment, Galileo suggested
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if you drop two objects of different masses
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off the Leaning Tower of Pisa, a cannonball
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and a wooden ball, they'd both hit the ground
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at the same time.
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But thought experiments are for babies
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so I'm gonna test the theory by jumping
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out of a plane with an orange
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to see who hits the ground first.
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The problem is, I'm not gonna be jumping
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out of a plane into a vacuum so I've got to figure out
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someway to account for air resistance.
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The atmosphere is made up of lots and lots of stuff.
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And those gases and other bits and pieces
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act like a brake, slowing things down.
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We call this breaking effect air resistance.
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Because I don't have a 10,000 foot high vacuum chamber
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to free fall in with my orange, I'm gonna have
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to jump out of a plane into the actual air.
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Which means first, I'm gonna have to drop
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a whole bunch of stuff from this crane
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to see what impact air resistance has on falling.
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First up, something light compared with something heavy.
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Obviously dropping them both at the same instant
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is really important so how we're doing that
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is compressed air cylinder.
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So when I push a button, that fires off two
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air operated pistons, it releases both carabiners
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at the same time, and they drop at exactly
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the same instant.
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Fridges aren't exactly renowned
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for their aerodynamic qualities.
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A match up with this feather pillow
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is likely to be a one sided demonstration.
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Professor Stuart Bradley knows a lot about gravity,
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so he's going to make sure we get the sciency bits right.
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My prediction is, that because of the issue
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or air resistance, the fridge will hit the ground first.
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Which isn't a ground breaking theory per se,
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but it should still be ground breaking
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in a more literal sense.
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All right, so now it's live.
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Three, two, one.
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(latch snaps)
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Whoa.
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(fridge smashing)
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Scientifically, hurt your thoughts? (laughs)
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I think the fridge is out cold.
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(laughs)
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The pillow ended up about a block down the street,
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while the fridge definitely hit the ground first.
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So what does this tell us?
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The two main factors affecting the outcome
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of this contest were the weight of the fridge
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and the aerodynamic qualities of the pillow,
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which was more effected by air resistance
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relative to its weight so it fell slower.
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Now let's drop two objects with similar aerodynamic
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qualities just like Galileo's Leaning Tower experiment.
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An oversized tennis ball and a bowling ball.
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They're both round and about the same size,
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so I'm expecting they'll handle air resistance
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in a similar manner.
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The difference is the bowling ball weighs a lot more,
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therefor the smart money has the bowling ball
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landing well before the tennis ball.
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So three, two, one.
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(latch snaps)
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I was right (balls crashing) but not by much.
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(laughs)
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Now we know what happens to a bowling ball, don't we?
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Never drop a bowling ball off a crane.
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(laughs)
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Turns out the bowling ball and tennis ball
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were fairly different.
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The bowling ball was heavier and the fuzz
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on the tennis ball created more air resistance
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than the smooth surface of the bowling ball
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so it landed a full two seconds later.
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But what about me and my orange?
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What might happen to us as I jump from a plane?
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Time to drop a dummy me and a real orange
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from a crane to find out.
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Because I've never jumped out of a plane before,
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you don't have to jump in tandem so we've added
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some diving weights to our dummies to bulk
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them up to 162 kgs to match the combined weight of me
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and the tandem master.
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If it will weigh over 1000 times more than the orange,
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we need to get some idea what difference
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air resistance makes to see if this is even
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going to be possible to film.
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Three, two, one.
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(latch snaps)
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Oh.
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See I'm not thinking about this experiment,
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I'm thinking about the actual
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jumping out of a plane at this point.
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(dummies crashing)
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Interestingly, the 100 gram orange, having a dimpled
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surface with aerodynamic qualities closer
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to our bowling ball than our tennis ball,
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fell almost as fast as the 162 kg dummies did.
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Which makes me hopeful we can actually film this.
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Next I use a rollercoaster to see what gravity
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feels like on different planets.
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I've got a twisty twisty (laughs).
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And dodge it at 5000 feet.
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Gravity's a constant so unlike us it never rests.
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And that also means that it effects us
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in all kinds of interesting ways.
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So in the morning
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I'm this tall.
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But when I return home at the end of the day
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what I find is that I'm now about a centimeter shorter.
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And that's because over the course of the day,
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the mass of my body has been attracted
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by the gravitational pull of the mass
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of the earth and I've shrunk.
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And it's not until nighttime when I lie down
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and let my spine stretch out that I return
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to my normal height.
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Try the experiment yourself if you'd like.
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The earths mass is six billion trillion tons
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which is why it's gravitational pull is so strong.
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But gravity is both powerful and weak
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because this small magnet is strong enough
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to overcome the earths gravity and stick to the lamp.
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At small scales like our magnet, gravity is very weak
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when compared to other forces like magnetism.
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But the bigger an object gets
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the more important gravity becomes.
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And once an object is very, very big like the earth,
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gravity eventually wins out over all other forces.
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You can see this when you jump or kick a ball.
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It's easy to get a ball flying through the air
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but it's much, much harder to get the ball into space
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because gravity is constant and relentless.
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With the help of an app developed
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by the University of Auckland I want to demonstrate
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that anything, whether it be a bullet
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that you've just fired from a gun or a ball
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that you've just kicked, falls towards the earth
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at a constant rate of 9.8 meters per second squared.
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That sounds strange but it's true.
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The app cleverly shows us that what we think
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we see happening, isn't.
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It looks like the ball is accelerating upwards
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but the app shows its vertical speed
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is actually decreasing.
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When it reaches the top of the arch,
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the vertical speed becomes negative as the ball
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starts to fall back to the ground.
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The graph shows the ball accelerates downwards
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at a constant rate the whole time.
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Which means me and my orange will as well.
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And it must be true because the app said it is.
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(electronic music)
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I know what gravity feels like here on earth
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but what about on a much bigger planet
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or a much smaller one?
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Here on the earth, we call our everyday gravity one g.
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But what does it feel like when gravity's increased
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to say, two g on a bigger planet, or less than one g
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on a smaller one.
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What I need is a machine that manipulates
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my experience of gravity.
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Something with a lot of acceleration
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and deceleration as well a device for measuring
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how many gs I'm experiencing.
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Well luckily for me, such a machine already exists,
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the Rainbow's End rollercoaster.
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With kitted my seat out with an accelerometer.
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The small steel ball moves on a spring inside the tube
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and we'll be able to see it move up and down
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as the g forces change.
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Basically a rollercoaster is a simple machine
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that uses gravity.
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So what happens, as you're going up the noisy part
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you're storing gravitational energy.
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The higher you go the more energy you're storing
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and at the top, gravitational energy turns
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into kinetic energy which is the fun stuff.
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The up shot of all the twisting and turning
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is that my experience of gravity changes.
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Less than one g, all the way up to four gs,
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which is about twice what I'd feel on Jupiter.
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That's about two and half back to one.
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(electronic music)
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I've got a twisty twisty (laughs).
266
00:13:45,186 --> 00:13:47,686
Somewhere on the way back up to the top
267
00:13:47,686 --> 00:13:50,620
of the rollercoaster after about my 20th circuit
268
00:13:50,620 --> 00:13:52,430
and feeling a little like a 10 year old
269
00:13:52,430 --> 00:13:54,370
who's eaten one too many hot dogs,
270
00:13:54,370 --> 00:13:57,990
the novelty and wonder of gravity wore off.
271
00:13:57,990 --> 00:14:00,660
I started to wonder instead if there was a way
272
00:14:00,660 --> 00:14:02,533
escape gravity for a while.
273
00:14:07,690 --> 00:14:10,090
Next I use a converted jumbo jet
274
00:14:10,090 --> 00:14:13,530
to allow be it astronauts to experience weightlessness.
275
00:14:13,530 --> 00:14:14,850
It's pretty simple really.
276
00:14:14,850 --> 00:14:16,970
The jet climbs at a really steep angle,
277
00:14:16,970 --> 00:14:20,010
it levels off and then dives, creating a path
278
00:14:20,010 --> 00:14:22,090
called a parabolic arch.
279
00:14:22,090 --> 00:14:25,040
Now this isn't America, and we don't have a NASA.
280
00:14:25,040 --> 00:14:28,640
So instead, I'm going to achieve weightlessness
281
00:14:28,640 --> 00:14:29,753
in this little puppy.
282
00:14:31,527 --> 00:14:33,165
Head goggles inside.
283
00:14:33,165 --> 00:14:34,007
Get these locked.
284
00:14:35,360 --> 00:14:38,100
This is Wayne Ormrod, he's an aerobatic pilot.
285
00:14:38,100 --> 00:14:40,284
He does this stuff all the time.
286
00:14:40,284 --> 00:14:42,920
(engine whirring)
287
00:14:42,920 --> 00:14:45,480
His plane is called a Racing Robin.
288
00:14:45,480 --> 00:14:47,570
And while it might be little, it's capable
289
00:14:47,570 --> 00:14:50,810
of speeds in excess of 300 kilometers per hour
290
00:14:50,810 --> 00:14:53,700
and is able to fly anywhere from minus three gs
291
00:14:53,700 --> 00:14:57,493
to six gs, which makes the rollercoaster sound timid.
292
00:14:59,380 --> 00:15:02,440
He's confident now, that in between all the swooping
293
00:15:02,440 --> 00:15:05,493
and diving, we can experience weightlessness.
294
00:15:06,563 --> 00:15:09,396
(engine whirring)
295
00:15:11,770 --> 00:15:14,430
A parabolic arch is pretty simple.
296
00:15:14,430 --> 00:15:18,810
Robin climbs fairly high, dives steeply to build up speed
297
00:15:18,810 --> 00:15:20,730
and then loops up in a flight path
298
00:15:20,730 --> 00:15:22,170
called a parabolic arch.
299
00:15:23,960 --> 00:15:27,593
NASA do this in a jumbo jet at 30,000 feet.
300
00:15:28,610 --> 00:15:30,490
We're a lot closer to the ground here
301
00:15:30,490 --> 00:15:34,050
which adds to the anxiety but as promised,
302
00:15:34,050 --> 00:15:37,440
when the wee Robin goes over the top of the arch,
303
00:15:37,440 --> 00:15:41,600
I experience what feels like weightlessness.
304
00:15:41,600 --> 00:15:44,060
I brought a clear globe filled with water
305
00:15:44,060 --> 00:15:45,743
to show the effects of gravity.
306
00:15:51,100 --> 00:15:54,110
We haven't escaped gravity but momentum
307
00:15:54,110 --> 00:15:57,550
of our flight path makes it feel like we have.
308
00:15:57,550 --> 00:16:00,833
It only lasts a few seconds, but it's magic.
309
00:16:15,120 --> 00:16:16,890
Enough of all this mucking about
310
00:16:16,890 --> 00:16:20,320
with orbs of floating water and levitating frogs.
311
00:16:20,320 --> 00:16:22,550
No matter how cool it might be,
312
00:16:22,550 --> 00:16:25,063
it's time to try out our orange.
313
00:16:26,123 --> 00:16:28,956
(uplifting music)
314
00:16:41,130 --> 00:16:44,860
Even if only for a moment or two, the orange,
315
00:16:44,860 --> 00:16:49,013
the plane and I all hang suspended above the earth.
316
00:16:51,241 --> 00:16:54,074
(engine whirring)
317
00:16:56,930 --> 00:16:59,970
So Galileo's famous thought experiment
318
00:16:59,970 --> 00:17:01,803
is looking pretty sound.
319
00:17:02,970 --> 00:17:05,300
But I didn't get where I am today by thinking
320
00:17:07,300 --> 00:17:09,687
so it's time to put all the science to the test,
321
00:17:09,687 --> 00:17:12,460
ignore that nibbling voice saying, "I'll die"
322
00:17:12,460 --> 00:17:14,303
and jump out of a plane.
323
00:17:15,389 --> 00:17:18,056
(Nigel screams)
324
00:17:23,841 --> 00:17:27,320
(electronic music)
325
00:17:27,320 --> 00:17:29,490
Galileo was a clever man.
326
00:17:29,490 --> 00:17:31,680
He theorized if you drop two objects
327
00:17:31,680 --> 00:17:34,840
with different masses, a cannonball and a wooden ball,
328
00:17:34,840 --> 00:17:38,140
off the Leaning Tower of Pisa, they'd fall at the same rate.
329
00:17:38,140 --> 00:17:40,850
My plan is to push his thought experiment
330
00:17:40,850 --> 00:17:43,680
into the 21st Century by throwing myself
331
00:17:43,680 --> 00:17:48,410
out of an airplane with an orange at 12,000 feet.
332
00:17:48,410 --> 00:17:51,320
Along the way, I've tested the law of gravity
333
00:17:51,320 --> 00:17:52,450
to its extremes.
334
00:17:52,450 --> 00:17:55,060
From experiencing all too brief moments
335
00:17:55,060 --> 00:17:57,410
of weightlessness in a stunt plane,
336
00:17:57,410 --> 00:18:00,290
to being squashed down on my seat under four gs
337
00:18:00,290 --> 00:18:01,723
of force on a rollercoaster.
338
00:18:02,920 --> 00:18:04,007
I've had a twisty, twisty (laughs).
339
00:18:07,458 --> 00:18:09,240
What I can't stop thinking about though
340
00:18:09,240 --> 00:18:11,370
is if the orange and I hit the ground
341
00:18:11,370 --> 00:18:14,030
from a great height, then I'll be dead.
342
00:18:14,030 --> 00:18:16,270
So I'm going to need a parachute,
343
00:18:16,270 --> 00:18:19,100
but I've never parachuted or free fallen before
344
00:18:19,100 --> 00:18:22,440
so to prove Galileo right, I'm also going to need
345
00:18:22,440 --> 00:18:24,920
a tandem jump master.
346
00:18:24,920 --> 00:18:27,990
I'm here in Taupo because it's time
347
00:18:27,990 --> 00:18:32,990
to jump out of a plane with my orange at 12,000 feet.
348
00:18:38,689 --> 00:18:40,683
Perfect, start those legs.
349
00:18:44,120 --> 00:18:45,310
It's a bit Biggles isn't it?
350
00:18:45,310 --> 00:18:47,703
I feel like I should be flying Sopwith Camel.
351
00:18:49,840 --> 00:18:51,380
I have to confess at this point
352
00:18:51,380 --> 00:18:53,540
that I said I'd never do a parachute jump
353
00:18:53,540 --> 00:18:55,450
because I've always been convinced the parachute
354
00:18:55,450 --> 00:18:57,230
wouldn't open and I'd die.
355
00:18:57,230 --> 00:18:59,280
Still, here we are.
356
00:18:59,280 --> 00:19:01,980
According to the experts, this is a complete
357
00:19:01,980 --> 00:19:03,220
waste of time.
358
00:19:03,220 --> 00:19:05,420
What's more likely to happen, is the orange
359
00:19:05,420 --> 00:19:07,890
will take off and never be seen again.
360
00:19:07,890 --> 00:19:11,050
But if Galileo and I have one thing in common,
361
00:19:11,050 --> 00:19:12,120
it's stubbornness.
362
00:19:12,120 --> 00:19:15,197
And like Galileo said, "In questions of science
363
00:19:15,197 --> 00:19:17,347
"the authority of 1,000 is not worth
364
00:19:17,347 --> 00:19:20,040
"the humble reasoning of a single individual."
365
00:19:20,040 --> 00:19:20,990
Good enough for me.
366
00:19:21,950 --> 00:19:23,510
The hardest thing about this, is that when
367
00:19:23,510 --> 00:19:26,120
we jump out, I'm holding the orange
368
00:19:26,120 --> 00:19:28,280
and my brain is gonna be telling me
369
00:19:28,280 --> 00:19:30,760
to squeeze whatever's in my hand really hard
370
00:19:30,760 --> 00:19:34,055
because that's the only thing stopping me from falling.
371
00:19:34,055 --> 00:19:34,950
(laughs)
372
00:19:34,950 --> 00:19:36,860
And I know that's dumb, but I know that's
373
00:19:36,860 --> 00:19:38,010
what my brain will say.
374
00:19:39,010 --> 00:19:41,274
And this won't work if I crush the orange.
375
00:19:41,274 --> 00:19:44,107
(engine whirring)
376
00:19:48,752 --> 00:19:53,091
All I can think about at this point is falling and dying.
377
00:19:53,091 --> 00:19:56,091
(suspenseful music)
378
00:20:04,180 --> 00:20:06,390
So we're jumping at twelve?
379
00:20:06,390 --> 00:20:08,930
When we reach 12,000 feet, I'm leaving
380
00:20:08,930 --> 00:20:12,400
this perfectly nice plane and all the way down,
381
00:20:12,400 --> 00:20:14,850
when the parachute fails I'll be telling myself
382
00:20:14,850 --> 00:20:17,560
that I knew this was going to happen.
383
00:20:17,560 --> 00:20:20,203
Still, no backing out now.
384
00:20:20,203 --> 00:20:23,203
(suspenseful music)
385
00:20:48,580 --> 00:20:52,633
The feeling when you first jump is mind blowing.
386
00:20:58,830 --> 00:20:59,673
Here we go,
387
00:21:00,580 --> 00:21:02,290
it's floating.
388
00:21:02,290 --> 00:21:04,790
Just like in the plane, it actually looks
389
00:21:04,790 --> 00:21:07,150
like the orange is floating.
390
00:21:07,150 --> 00:21:10,120
Incredibly, and against all hope,
391
00:21:10,120 --> 00:21:12,333
we all hang together in midair.
392
00:21:13,200 --> 00:21:15,910
And suddenly, I'm not thinking about dying,
393
00:21:15,910 --> 00:21:19,000
I'm thinking about Galileo and gravity
394
00:21:19,000 --> 00:21:21,283
and how science lets us understand things
395
00:21:21,283 --> 00:21:23,970
like the oddly beautiful sight
396
00:21:23,970 --> 00:21:27,033
of an orange falling from 12,000 feet.
397
00:21:28,280 --> 00:21:30,120
My tandem jump master and I
398
00:21:30,120 --> 00:21:32,100
are putting up too much air resistance
399
00:21:32,100 --> 00:21:34,400
to fall quite as fast as the orange,
400
00:21:34,400 --> 00:21:36,470
but our cameraman is able to change
401
00:21:36,470 --> 00:21:39,370
his body position, reduce his air resistance
402
00:21:39,370 --> 00:21:42,430
and save the orange from a splattery death.
403
00:21:42,430 --> 00:21:45,263
(uplifting music)
404
00:21:46,708 --> 00:21:48,541
It's flawless, genius.
405
00:21:49,709 --> 00:21:52,089
That was everything
It caught us.
406
00:21:52,089 --> 00:21:54,172
(laughs)
407
00:21:57,350 --> 00:21:59,100
That was really good.
408
00:22:01,830 --> 00:22:05,460
Our experiment has been a complete success.
409
00:22:05,460 --> 00:22:08,393
Turns out Galileo was right, who would've guessed?
410
00:22:09,240 --> 00:22:11,970
My tandem master and I, have a combined weight
411
00:22:11,970 --> 00:22:16,470
of 162 kilograms yet we fell at the same speed
412
00:22:16,470 --> 00:22:19,750
as a piece of fruit, one and half thousand times
413
00:22:19,750 --> 00:22:21,070
lighter than us.
414
00:22:21,070 --> 00:22:24,560
It seems to defy all logic, so what happened?
415
00:22:24,560 --> 00:22:27,520
Well, this illustrates one of the weird things
416
00:22:27,520 --> 00:22:28,710
about gravity.
417
00:22:28,710 --> 00:22:31,600
The weight, or mass, of me and the orange
418
00:22:31,600 --> 00:22:33,430
isn't the deciding factor.
419
00:22:33,430 --> 00:22:35,640
It's the mass of the earth that counts.
420
00:22:35,640 --> 00:22:38,570
All those billions of trillions of tons
421
00:22:38,570 --> 00:22:41,450
exert the same power of attraction over me
422
00:22:41,450 --> 00:22:43,043
as it does to my orange.
423
00:22:44,930 --> 00:22:49,930
So gravity's a complicated but elegantly simple thing
424
00:22:49,960 --> 00:22:54,660
because basically what we've seen is that
425
00:22:54,660 --> 00:22:58,780
if you account for mass, which is pulling you down
426
00:22:58,780 --> 00:23:01,800
and wind resistance which is pushing you up,
427
00:23:01,800 --> 00:23:03,900
then two objects of quite different weight
428
00:23:04,760 --> 00:23:07,220
can fall at pretty much the same speed.
429
00:23:07,220 --> 00:23:08,363
Me and my orange.
430
00:23:09,360 --> 00:23:11,160
But mostly I think we've just proven
431
00:23:12,117 --> 00:23:14,873
that Galileo was a genius.
432
00:23:14,873 --> 00:23:17,706
(uplifting music)
33292
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