So, if gravity pulls everything down, then why don't things on the bottom of the
Earth get pulled down into space? In this episode of Crash Course Kids,
Sabrina talks about gravity and explains that when we talk about gravity pulling
things down, what we really mean is gravity is pulling things TOWARD the Earth.
Really, it's all about attraction.
If I told you that you just won the lottery, what would you do? If you're like me,
you'd jump up and down and scream. And after you are done freaking out and
jumping in the air, you'd *landing sound land on your feet, right?
But WHY would you land back on the ground instead of just floating off into space?
It's because of a little something we call gravity. Gravity is what pulls everything
toward the ground. Including you! Without the force of gravity, there would be no
life on Earth. Air, water, animals? Everything would fly off into space. There'd be
no you, no me, on french fries; nada. Think of gravity like the invisible superglue
that holds our massive world together. You can't SEE it, but it's always there.
An English scientist, named Isaac Newton, was the first person to seriously study
gravity (over 300 years ago). There's a famous story about him that you might
have heard. Supposedly, Sir Issac was hanging out underneath an apple tree
thinking, -PROBABLY partly napping- when an apple fell from the tree and
conked him on the head. That's when Sir Issac had an "aha moment.
” Why did the apple fall down to the ground, and not up, or sideways?
He realized that a special kind of force, which we now know as gravity,
was acting on all of the objects on earth; pulling them toward it.
Once the apple became too heavy for its stem to hold it anymore, the
gravitational pull of Earth brought the apple down on to Newton's noggin.
Newton also realized it doesn't matter how heavy an object is either.
Whether you're holding an apple, or a bowling ball, or a feather. if you let
go of it, that sucker's going down. We're gonna make a whole video about
this late. Basically he determined that what goes up must come down.
Sir Isaac was a pretty smart dude. Okay, so you know that if you jump up,
you'll eventually land back on the ground and you know that an apple
drop-down will land on the ground too, To see how gravity will act, pick
up the tennis ball or any small, round object and hold it in your hand.
Let's toss it in the air and watch it fall to the ground. No surprise here,
okay now pick it up and hold it over your head. Let go and watch it fall
once more. Again, not a shocker. Now throw it to your left. Ball down.
Pitch it to the right and watch it go down again. No matter where you throw
the ball, it's going down. So, we've determined that near the surface
of the earth (where we all are), gravity is the cause that produces the
effect of all unsupported objects falling down. The ball will go up or to
the left or to the right for a little bit, but eventually it's going to be pulled
back down to the ground, no matter what.
Gravity's got a hold on... well, everything.
1. Define what gravity is.
2. Would you like to experience zero gravity and weightlessness
3. Would you like to go to the moon or travel into space? Why or why not?