(bright upbeat music) - [Mr. C] What time is it?

- [All] It's science time!

♪ Science, science, science time ♪ ♪ Let's all stop and just unwind ♪ ♪ One, two, three, four, here we go ♪ ♪ Learn so much your brain explodes ♪ ♪ Lessons so cool and so fresh ♪ It's so great you'll lose your breath ♪ ♪ Learn new facts and real cool stuff ♪ ♪ Scream for more, can't get enough ♪ ♪ It's, it's science time ♪ It's fun, you best believe it ♪ ♪ Explore and learn new things ♪ Come and join me please - I'm Mr. C and this super smart group is my science crew.

Lyla is our notebook navigator, Alfred is our experiment expert, Rylee is our dynamite demonstrator, and London is our research wrangler.

Working with my team is the best.

It makes learning so much fun.

Actually, you should join us.

Today, we're learning about kinetic and potential energy.

What time is it?

- [All] It's science time.

- Welcome back to another episode of DIY Science Time.

I'm Mr. C and I'm so glad that you're here to be part of our science crew today.

(whip cracking logo theme) In fact, we have some fan mail.

I can't believe it.

We got some fan mail.

(Mr. C woofing) Yeah, let's see what's inside.

(envelope creaking) What?

That's not even cool.

Someone played a trick on us.

What is this thing?

Oh my gosh!

It's like those... Look at this.

You wind it up.

(laughs) That's hilarious.

And then when you let it go, (upbeat music) all of the stored energy makes it spin.

And it makes all the sound because, well, it's hitting that paper.

I think this is a great idea for our show today.

I see, potentially, the greatest show ever.

Yeah.

Let's do potential and kinetic energy.

Let's talk about how this, right now, stores energy, and when we let it go, it puts it in motion.

I've got some great ideas that we can do.

Alfred, what materials are we gonna need?

- You'll need the following materials for your racer.

A straw, two plastic or foam cups with lids, rubber bands, tape, a few paperclips, and, of course, our science notebook!

- A science notebook is a tool that every scientist should have, and it gives us a place to record all of our learning.

Taking good notes and being organized allows us to be better scientists.

A science notebook allows us to go back and review all the data and information we've gathered during our experiments.

Plus, it allows us to share results with other scientists who might be interested in learning more about what we've discovered.

Whenever you see the notebook pop up on the screen like this, it's a reminder that this is a good place for us to jot down new information.

You can see I've already added a title and the list of materials for today's activity.

Our crew is still going to have lots of information to collect and organize as we go through the experiment.

So keep your notebook handy.

Most importantly, the more you use the science notebook, the better you'll get at taking notes and recording data.

If you don't have a science notebook yet, download a copy of Mr. C's science notebook from the website.

- Let's actually build a rubber band cup racer.

We're gonna take this idea of potential energy that's stored in the rubber band when we twist it and turn it into kinetic energy, energy in motion, so that we can actually have these racers.

Well, you'll have a racer that you can race with friends and family at home.

So we have our materials and it doesn't really matter what size rubber band you have.

My only recommendation is that you have to have the same.

So I have these red ones, these yellow ones, these brown ones and we're going to simply just pick two of them.

I'm gonna go with red because you can see 'em through the cups really easily.

So I have my two rubber bands and I'm gonna start with these plastic cups.

These cups also have lids on them.

So you're gonna want two cups that have lids because that's going to allow you to seal it and to connect everything together.

So the first thing we do...

The first thing we do is we poke a hole in the center and I'm using a push pin because I can grab onto it and put a little hole in the bottom of both of these.

(cups popping) I wanna take a pair of scissors and I'm going to make the hole bigger.

And I twist that so I get a nice hole to put the rubber band through.

You wanna try to get it in the center as much as possible because we're gonna run these rubber bands through here.

Now, what we're gonna do is we're gonna stack them.

All right.

I think we'll be okay.

And then we're gonna take a piece of tape.

Got some blue tape.

Take a nice long piece and I'm going to connect these two right in the center.

And let's make sure we're rolling.

Yeah.

Look at that.

Set that over to the side, just for a second.

And now comes the part where we have to connect two rubber bands.

And the way we do that is we take one rubber band and we pull it through like this and then we go underneath the same part.

Magic.

(Mr. C laughing) That didn't work.

All right.

So I have my two rubber bands and I'm going to pull one rubber band through just like this.

I'm gonna hold it.

And now I'm gonna pull this one through underneath.

There we go.

And now the most difficult part of the day, getting this through here and I'm gonna use my pencil to help guide it.

That wasn't too bad.

All right.

I'm gonna keep the pencil in there, just for a second, because it's gonna help prevent the rubber band from shooting through.

I'm going to put a lid on this side here in just a second, but I have to bring this rubber band through here.

I'm gonna bring it through the hole on my lid just like that.

And now on this side, I'm just gonna put a paper clip like that, just to hold it just for a second.

All right.

And that's gonna keep the rubber band from shooting back through because we're actually stretching it and it's starting to stretch and it's starting to store energy because we're stretching it and it's going to want to actually rip out.

So now that I have this one, I'm gonna pull my pencil out just like that.

And we're gonna do the same thing on the other side.

(upbeat music) I'm gonna push this through the opening.

Whoops!

(cups creaking) Pop that on.

And we're going to take a paper clip and we're gonna hold it in place.

And so now we have the insides ready to go.

So we have the engine which is the rubber bands.

And when we get the rubber bands to spin, it stores up energy, but right now it's gonna be hard to spin it.

So what we have to also do on this side is you're gonna pick one of the sides, and you're gonna take one of these washers, (upbeat music) and I'm also gonna take one of these pony beads.

Let's see, orange, my favorite color.

(upbeat music) Pull that through.

And now I'm going to take a straw.

I'm using, that's a jumbo straw.

I have other straws too, just in case, 'cause I'm not sure how the jumbo straw is gonna work.

I'm gonna put that there to hold it, and then I'm gonna pull that out.

I'm gonna pull that paper clip out.

I'm nervous 'cause it's pulling in.

So we'll see how this works.

But now, look at that.

We have our car.

You're wondering how do we get it to work.

Well, you have to wind up one side.

(upbeat music) And you can keep winding and winding and then when you set it down... (Mr. C laughing) Can you send that back?

(Mr. C laughing) Come back, my little car.

That's so awesome.

And look when I take it off, it spins a little bit because that's the stored energy in the rubber band.

So that is a really easy and fun way to build a rubber band car racer.

And here's the thing, if you have more than one, you can race them with your friends and family.

Three.

Two, one.

Whoa!

He was going the wrong way.

(laughs) Whoa!

Whoa!

(rubber band car racer smacks on the floor) It went right off the table.

- Ahoy, matey!

Grab an empty juice carton and use rubber bands to hold the two craft sticks to the sides.

Cut a piece of cardboard and cover it with tape to help make it more water resistant.

Connect the paddle to the rubber band and wind up your boat.

Place it to the water and let it go.

Shiver me timbers!

You got your very own pirate ship.

- Check this out.

I built this really cool track and it's like a roller coaster for these steel marbles.

(steel marbles rolling) Isn't that awesome?

You can see the motion of the marble, back and forth, back and forth.

But here's the question I have for you.

Which of these tracks is going to allow the marble to travel back and forth the fastest?

I think we should try that.

And then we'll talk about the track and how we built it and why it actually works the way it does.

All right, here we go.

(upbeat music) Three, two, one.

(steel marbles rolling) Whoa!

Did you see that?

This track here allowed the marble to travel over faster and return faster than the top track.

And the question is: why?

Why?

So in order to understand this, we really have to talk about kinetic and potential energy.

These tracks are both set at the same height.

So they're both starting at the same point.

So I can have the marbles start at the same exact point and when I let go, (steel marbles rolling) something changes right here.

It's the potential to kinetic energy conversion.

When the marble is here on both tracks, they both have the same potential energy, stored energy, because they're off the ground the same amount.

When the ball starts rolling, they're both traveling the same speed right here because they've had the same amount of potential energy converted into kinetic and they're rolling here at the same rate.

But at this point, when this marble up here continues going flat, across the upper bridge, this one here drops.

And when it drops, it takes more of that potential energy and converts into kinetic energy, which causes it to travel faster.

So right here we have where it takes off faster and it does that on both sides.

So if you watch really carefully again, (upbeat music) (steel marbles rolling) you can actually see that they're both basically at the same point, and then when it hits the ramp here, it just takes off.

I'm gonna take these one inch steel marbles and replace it with this two inch.

Oh my gosh!

They're so much heavier.

They are literally just monsters.

So we're gonna actually try this one now on the ramp and let's see if it does the same thing.

Do you think it's going to have an impact?

Let's give it a try.

In three, two, one.

(steel marbles rolling) It behaves exactly the same way.

That is super cool.

That is super cool.

And so this is just a fun way that we can actually look at the conversion from potential energy to kinetic energy.

And you could build something like this at your house even if you don't have metal rails like this or a big piece of wood, grab some straws and a marble, build a track where the marble can cross over the straws and travel along that.

And you can build little ramps and see if it does the same thing.

Potential energy, also known as stored energy, is energy that is held by an object because of its position relative to other objects.

Kinetic energy is energy in motion.

As we take an object and lift it higher off the ground, it gains more potential energy.

When you hold an object above the ground, it has potential energy, but no kinetic energy.

However, the moment you let go, the potential energy of the object decreases as it falls while the kinetic energy increases.

All right, get that tied up there.

bring the string down.

And what we have here is a pendulum.

Look at this.

I tied a piece of string up to the ceiling.

I have my bob which is the weight on the bottom of a pendulum.

And this is actually a lacrosse ball.

Side note, my daughter plays lacrosse.

It's an awesome sport.

And then I have it attached to the string here and I have the string coming out of the top of the screw.

So I drilled a screw in there so that I could get this to swing back and forth.

Now, a pendulum does exactly what it's doing right now.

It's swings back and forth.

And another cool thing about a pendulum is that when you swing it back, the time it takes for it to get from Point A, over there to you, and back to here is called the period.

So I can let this go.

Let's come back really far.

Let it go.

And that's the period.

So we can actually count it (mumbles) one, 1000, two, 1000.

So the period of swing for this pendulum is two seconds.

The period is two seconds.

And the really cool thing about a pendulum is that right here, it's at rest.

So the string is stretched as far as it can go and it's hanging right here.

It's moving just a little bit, but it's hanging right here.

And we can say right here that it isn't doing anything.

But when I start to move the pendulum this direction, it's actually gaining potential energy.

See the height of the bob is getting up further away from the table as I stretch it out and that is potential energy.

It's gaining potential energy.

The higher I bring it, the higher the potential energy.

And then when I let it go, that potential energy is converted to kinetic energy or energy in motion.

And what's happening here is... We're gonna stop it.

This right here is the highest point for the swing.

That means it has the most potential energy that it can have in the system.

When I let it go and it swings and then stops, well, it doesn't stop, but when I go as it's moving through the swing, the lowest point, once I let go, that's where it has its highest kinetic energy, the most energy in motion because at that point there is no potential energy because it's at its lowest point.

So in this system, we're converting from potential, kinetic, potential, kinetic, potential, kinetic, potential, kinetic.

That motion keeps going and going and going.

And what I love about this is you can have some fun with it also.

So I stacked up some cups over here to my left, to your right.

Yeah, over here.

And what I'm gonna do is I'm gonna actually take this and I'm just gonna give it a little push.

(plastic cups clanging) Push!

(Mr. C laughing) That is the power of lacrosse ball swinging as a pendulum.

But here's the thing, we're gonna try that again, but this time we're gonna use my little friend, Little C. This is actually a doll of my daughter and we use her for science experiments sometimes.

Are you ready?

"I'm ready Mr. C. Let's do this."

All right Little C, here we go.

So we're gonna do the same thing.

We're gonna bring this, I gotta make sure it doesn't hit the container, right up to her chin.

And the question is: is it gonna hit her chin?

And we're only doing this with a stuffed animal because we don't wanna do this with a real person.

We don't wanna get anybody hurt.

And so I'm gonna let this go in three, two, one.

(upbeat music) It doesn't get her.

The question is: why does it not get her and it knocked over those orange cups?

And the answer is simple.

I don't know if you paid attention, but when I had the orange cups, I actually gave it a little push and I gave it extra energy which caused it to come back up.

And we'll do that here with her.

We're gonna give it just a little extra push.

And there it hits her, but when we just hold it and let go, it can't hit her.

And that's because the system has the most energy right here, right now, and when I let go, it can't get any more energy from anywhere.

Even though it's going potential, kinetic, potential kinetic, potential, kinetic, potential, kinetic, it doesn't change the fact that it's not gaining energy, in fact, it's losing energy to friction.

The string up there where it's pivoting is rubbing a little bit so it's slowing it down.

The ball is moving through air and air creates air resistance which is the type of friction.

So this is not a perfect system, but what's really cool is you can have some fun working with pendulums.

And watch this.

I bring this all the way back from me to you.

Whoa!

And it doesn't get me.

And that's all because of potential and kinetic energy.

- The first roller coaster opened on June 16, 1884 in Brooklyn, New York.

Roller coasters are able to race on their tracks because of potential energy.

If you've ever ridden on a roller coaster, you know that the first hill is the tallest and honestly the best.

In order for the cart to make it over to second hill, the first hill must be taller.

Yippee!

- Build two pendulums and attach them to a single suspended string.

Pull back on one of the pendulums and let it swing.

Watch the pendulums and before you know it, the first pendulum begins to slow down and the second pendulum begins to swing.

This isn't magic, it's science.

The first pendulum's energy is transferred through the string and goes to the other pendulum.

This causes the second pendulum to begin swinging.

This process will continue back and forth until there isn't any energy left in the system.

- (gasps) A can!

It's a can.

Can you believe it?

I can.

All right, little can.

I know you've got it in you.

Here we go.

(upbeat music) Wait a minute.

That can can roll all by itself.

Can you believe it?

Something is happening inside of this can.

What do you think it is?

I think it has a little bit of potential.

What do you think?

All right, let's build one of these.

So I've got some materials over here.

You're gonna need a rubber band, something that has some mass, I'm gonna use this nine-volt battery.

You could also use some hex nuts and some paperclips.

So a pretty simple build, but the most important thing is you're going to need a cylinder of some sort that you can poke a hole in the bottom and poke a hole on the top.

Once you have a hole in the bottom and the top, you're gonna unscrew the lid.

And then what you're gonna do is you're gonna take your mass.

Now, my mass, if I have it... My hand doesn't fit very well.

If I have it like this, it's not gonna fit too well.

So I'm gonna actually have it horizontal in there versus vertical.

So I'm gonna lay that down horizontally, and then I'm going to take one of my thicker rubber bands, give it a little bit of a stretch at the start, and I'm gonna put it right there and I'm gonna tape that down with some tape.

(upbeat music) So I'm trying to tape it right in the middle.

(upbeat music) And then you can see that I'm gonna have to stretch it from one side to the other in my container.

So that's nice and good there.

I'm gonna put this into this just like this, and slide this part of the rubber band through, and I'm gonna take one of my paperclips.

(groans) My hand!

And then I'm gonna get that on there.

Now, when I pull the rubber band and stretch it, it doesn't pop through and we do that to the other side as well.

I'm gonna have to extended it past the opening.

That is powerful rubber band, let me tell you.

(groans) (Mr. C laughing) There we go.

Get that on there.

I'ma twist that.

(upbeat music) Pop this through there, so the rubber band can't come through and now we have our self retrieving can.

Yeah.

Here we go.

Move away my other materials.

So this is how it works.

Look, I didn't even touch it and it's already going.

(upbeat music) Isn't that awesome?

So what happens is when we twist the rubber band, the rubber band twists and it winds up.

It's storing elastic energy which gives it potential energy.

Because this mass is right there, it doesn't allow the rubber band to spin with the rest of the container.

And because of that, it gets twisted and when I let it go, it's gonna go in the opposite direction.

Yikes!

Come back.

Nice.

I knew you could do it.

You're just as good as this can.

In fact, I like this one better 'cause I can see what's happening.

And when I spin it forward towards you, you can probably see the rubber band winding up.

And if I really simply, just give it a little bit twist, you can see that the nine-volt battery spins around that's because of the stored energy.

So this time, instead of the container spinning, the battery spun in the opposite direction.

See if I push it out... Come back!

That is so awesome.

What if we try this?

All right.

I'll turn it this way so we can see everything.

Well, you can't see anything in this can, but this one you can.

All right, here we go.

Let's push them away from each other.

(cans slamming) (laughs) That's so cool.

I bet you can build one of these also.

Give it a try.

- This could potentially be my favorite set of experiments we've done.

We've been so busy learning about potential and kinetic energy.

From the cup racer to the up and down energy track.

We've seen some seriously cool energy conversions today.

Mr. C's designs are great, but I bet there's some ways to improve them.

Take the DIY challenge today.

- You are absolutely right, Lyla.

All of my designs and my experiments always have room for improvement.

And working with my crew, that's what this is all about because together we have so much potential.

My crew here and all of you at home, when we're having fun learning together, man, we can explore anything and know that we can be successful.

And speaking of which, you wanna make sure you have your science notebook so you can record all of the data and information that you gather during your experiments.

If you don't have one yet, hop online and download it.

I don't even know where to start.

Whether it's our retrieving cans, this track, our moving boats.

What an amazing day!

Keep learning.

Keep having fun.

Keep exploring and remember science is wherever you are.

(lively music) See ya!

♪ It's science time So let's actually build a rubber band.

And then I'm gonna take a pencil, and simply make that hole bigger, maybe.

I'm gonna take a pair of scissors.

(roars) All right, here we go.

And I'm gonna leave that up to you.

All right.

Keep building.

Keep racing.

Keep having fun.

♪ For everyone, everyone ♪ It's science time ♪ Yes, you best believe