Name: 降落伞的游戏时间|儿童物理（Playtime with Parachutes | Physics for Kids）
Uploaded: 2021-05-07T13:24:23.000Z
Duration: 3 min 37 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Have you ever played under a parachute at school?

You and your friends hold on the edge, flip it up toward the sky, and then slip inside

祈使句型

and watch it slowly float down on top of you.

Or maybe you've seen a skydiver jump out of an airplane!

After he jumps, he falls through the air, and then...he opens up his parachute!

The parachute slows the skydiver down, so he falls gently towards the ground and can

But have you ever thought about how parachutes work?

Well, in the end, parachutes work because of … air!

And, air, like everything else that you can feel, or that takes up space, is made

That's what scientists call, just, stuff!

The parachute, the air, the ocean, you, me, everything.

And since air is made up of matter, when you walk through the air, you're actually

pushing matter out of the way, with every move you make!

But here's the thing … that matter is pushing back on you, too!

You probably don't feel it when you're just walking around.

But when you start running, you might feel it a little bit.

And when you start to go even faster, like when you're speeding around on your bike

That feeling is the air pushing against you!

And this force has a name: It's called drag.

Drag is the force of the air pushing back on you, or on anything, when it moves.

And the faster something is moving, the more drag it feels.

So, you don't really feel the force of the air as you walk around.

But have you ever held your hand outside the window of a moving car?

You can feel the air pushing against your hand, and it can be hard to even keep it still!

But, have you noticed that it's easier to hold your hand flat, like this, than it

is to hold your hand so your thumb's pointing up, like this?

It's because when you hold your hand straight up like this, more air is bumping into your hand.

But when you put your hand flat, like this, only a small part of your hand is pushing

There's less of your hand for the air to run up against, which means less drag, so

your can glide through the air more smoothly.

So, what if you're a skydiver, and you're jumping out of an airplane?

How do you slow yourself down so you can land safely?

You'd want to do something that would make more air bump into you.

And that's how a parachute helps; it makes more space for the air to run into.

There's so much drag on the parachute, so much air pushing against it, that it slows

Now, a lot of other things experience drag, too!

When a boat moves through the ocean, the water that pushes back against it is also making drag.

And cars and trucks experience drag when they're driving down a highway.

A little car feels less drag than a big truck, because it has less space for air to push

So, drag is the force that you feel when you're moving through something, like the air, and

But it's what makes lots of things, from skydiving to playtime with parachutes, possible!

Do you have a question about parachutes, force, or anything else at all?

Ask a grownup for help, and leave us a comment down below, or send us an email to kids@thescishow.com!