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  • Hey it's me Destin, welcome back to Smarter Every Day.

  • So today we're in the rocket van and I've got two little science helpers here right?

  • Kids: Yes, right.

  • Are you wearing your seatbelts?

  • Yes.

  • OK we're gonna do something pretty interesting. Check this out.

  • I've got a pendulum suspended from the top of our family van

  • and we're just gonna drive forward, we're gonna accelerate,

  • so if we're going that way, which direction do you think this pendulum should go? What do you think?

  • 3.. 2.. 1.. Go.

  • Kids: Yes.

  • Which way is it going?

  • Kids: My way.

  • That's right. It's because I'm accelerating right?

  • Does that make sense to you guys?

  • Yes sir.

  • OK very good, I was hoping it would make sense.

  • So we're gonna change it up just a little bit.

  • OK so now what I'm gonna do is I'm gonna replace this pendulum with a balloon.

  • We should see the same thing right? Let me cut this off.

  • So what we're gonna do is we're gonna accelerate that way

  • so we have the mass of the balloon and the acceleration that should net in a force and will have to react with this string right?

  • You guys ready?

  • Yes sir.

  • 3.. 2.. 1.. Go.

  • Wait a second. What just happened?

  • What happens when I stop?

  • The balloon goes backwards when I stop.

  • What's happening?

  • 3.. 2.. 1..Go.

  • There it is. It's coming right at me.

  • Why's it doing that?

  • Do you wanna know?

  • Yeah.

  • Alright, I brought something to show you.

  • You remember I told you I was gonna bring this jar earlier? Remember that?

  • So it's like this. Imagine this entire van is just like this jar,

  • and all the air inside this van is just like the water in the jar. Does that make sense?

  • So let's imagine that the balloon is this bubble on top,

  • because the helium in the balloon is lighter than air right?

  • So that causes it to do what?

  • Kids: Go up.

  • Go up, that's right.

  • So if I've got this air that's just like it, what happens if I move the jar that way?

  • All that water sloshes to the back.

  • And when that water sloshes back this way, which direction does the bubble go?

  • You see that? So the air bubble moves in the direction of acceleration,

  • does that make sense?

  • I know you're five but I think you can get this.

  • OK so I've got my seatbelt on. If I drive forward real fast right now which direction is the balloon gonna go?

  • Forward.

  • Why will it go forward?

  • Because all the air's sloshing back.

  • That's right! Very good! Watch this.

  • Look at that. You see that?

  • So you know what that means don't you?

  • That means you have more air to breathe than daddy does when I'm going fast.

  • Did you realise that?

  • Kids: Nooo!

  • Yeah that means when I go fast, that means more air sloshes back there to you and you have more oxygen to breathe.

  • Doesn't it feel good back there?

  • OK so now we have the plumb bob right next to the balloon, so if I go forward they should spread apart right?

  • Let's check it out.

  • Is it working?

  • Kids: Yeah.

  • So what I want to do is I want to tell everybody on Smarter Every Day that if they go download

  • a free audio book that it'll help Smarter Every Day by sponsoring us.

  • Audible will, if they go to audible.com/smarter.

  • And so they get a free audio book, but I'm gonna do it in a funny way.

  • Now lean in towards me and look straight at the camera.

  • I know you don't know what I'm gonna do but don't laugh

  • because I want people to realize that they can send you to school if they get a audio book.

  • Does that make sense?

  • Yeah.

  • So whatever happens don't laugh. OK?

  • Look straight at the camera. Ready?

  • You don't know what I'm doing, do you?

  • OK you ready?

  • (High pitched helium voice) Thank you for supporting Smarter Every Day and if you would please download an audio book at audible.com/smarter.

  • Did you know daddy could talk like this?

  • No.

  • You didn't know that happened, did you?

  • So if you go get a free audio book it'll support Smarter Every Day and it'll help me send these kids to school.

  • Does that sound like a good idea?

  • Yes.

  • You should never do that, by the way. That's only for adults.

  • How'd you do that?

  • It's magical. Anyway I'm Destin, you're getting Smarter Every Day.

  • Please subscribe to Smarter Every Day and support our sponsor audible,

  • I'll leave a link somewhere and you can check it out.

  • Thanks, bye.

  • How'd you change your voice?

  • OK now we have the sunroof, the side window and the back open.

  • I'm gonna go forward, where do you think it's gonna go?

  • Daughter: Forward.

  • Son: Backwards.

  • 3.. 2.. 1..

  • Dad: So this is air, not helium?

  • Yes sir.

  • OK I think it's gonna act like the pendulum.

  • Dad: 3.. 2.. 1.. Go.

  • (laughs) Backwards.

  • Oh it does. We're gonna use that one.

Hey it's me Destin, welcome back to Smarter Every Day.

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B1 smarter balloon audio book pendulum audible audio

A Baffling Balloon Behavior - Smarter Every Day 113

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    黃翊丞 posted on 2014/05/11
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