(upbeat music) - [Mr.

C] What time is it?

It's science time.

♪ Oh it's 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, so fresh ♪ ♪ Feats so big, you'll lose your breath ♪ ♪ Learning facts some real cool stuff ♪ ♪ Scream for more, can't get enough ♪ ♪ It's it's science time ♪ ♪ It's fun, you best believe ♪ ♪ Explore and learn new things ♪ ♪ Come and join me, please ♪ - I'm Mr.

C, and this super smart group is my science crew.

Working together with my crew makes learning so much fun.

Actually, you should join us.

Let's give science a try with a simple DIY.

Today, we're exploring buoyancy.

What time is it?

It's science time.

Welcome back to "DIY Science Time".

My name is Mr.

C, and I'm so excited that you're here to be part of our crew today.

(computer whooshing) Today, we're talking about buoyancy.

That's right.

♪ Buoyancy, buoyancy, buh buh buoyancy.

♪ What?

♪ Buoyancy, buoyancy, buh buh buoyancy.

♪ Okay, I'll stop.

But we're gonna be talking about buoyancy, which is a property of fluid.

So whether we're talking about water or air, buoyancy applies.

And it makes me wonder.

Look at some of these objects that I have on the table.

Will they sink or will they float?

(upbeat music) Lacrosse ball.

(crew member sighing) Sinks.

Soda.

(computer whirring) Semi-floats.

Different soda.

(computer whirring) A lemon.

(crew laughing) (Mr.

C laughing) An apple.

(upbeat music) A metal steel ball.

Oh.

And you know what really floats my boat?

A boat.

Whee.

So gather some of the following materials so that you can also join me as we explore buoyancy.

Let's go.

- Sink or float?

We'll find out when you build your own aluminum boat of science.

You'll need to grab the following materials to participate in this engineering design challenge: pennies, scissors, tape, aluminum foil, a bucket or tank with water, and you'll definitely want to have your splishy splashy science notebook.

(computer whooshing) - A science notebook is a tool that every scientist should have because it gives us a place to record all of our learning.

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

A science notebook allows us to go back and review all of the data and information we 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 during the show.

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

But our crew is still going to have lots of information to collect and organize as we go through our experiments.

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

If you don't have a science notebook already, download a copy of "Mr.

C's Science Notebook" from the website.

- Boats float.

Say it with me, boats float.

And why do they float?

Because water has weight.

Water is heavy.

And that means things like huge ginormous ships can float in water.

Or I have a 3D printed little boat that can also float in water.

Now, this boat's not as heavy as a big metal ship, but I did put big heavy metal coins, half dollars, into the hull of my ship so that it'll add a little bit more mass for this experiment.

I'm going to place this boat into this water.

The water is going to displace.

And what that means is the water is going to go up because the boat is pushing its weight in water away.

And that means the water will go up, and we'll have water pour out of this side, hopefully.

So let's give it a try and let's see what happens.

(printed boat being twisted) (upbeat music) As you can see, the water starts to run out of the straw into my cup.

And what we're going to do here in a moment, we're going to take the water that's being displaced and weigh it to see if it weighs exactly as much as our boat with the coins.

And it should.

Because anything that floats displaces its mass in the weight of the water that it displaces.

Those two things should be equal.

However, everything displaces water.

Things that float displace water, and things that sink displace water.

Check out this little cup over here I have.

Well, it's actually a beaker.

I've got a beaker here with 150 milliliters of water in it already.

If I add this ball of clay into it, first let's see if it sinks or floats, it sinks.

And when it sinks, it doesn't displace its mass or its weight.

Instead, it displaces its volume.

That's the super cool thing about whether things float or they sink.

Either way, they displace water.

Say it with me, they displace water.

- [Computerized Voice] They displace water.

- This is going to keep running out.

And we're gonna let that go.

And once it's done, we'll measure the two and compare our numbers.

As you can see, the last driblets of water are coming out.

We wanna capture them all so that the mass of the water is as close to the mass of the boat with the coins as possible.

Before I take the boat out of the water and put it onto the scale, I just wanna show you that our scale is balanced.

The beaker has a mass of roughly 94 grams.

And I've countered that mass with just additional coins I had laying around the house.

I just wanted to make sure that this was balanced before I add any weight to the system.

So let's take our boat out.

I'm gonna dry the bottom off to avoid getting water, (printed boat twisting) extra weight, onto our scale on this side.

So we're gonna put the boat on.

And it takes the scale out of balance.

But what we're going to do now is we're going to carefully add the water that was displaced into this container, which should match this boat and the mass.

(upbeat music) It's almost perfectly balanced.

That is amazing.

And what's even cooler is I can take this off and I can put this onto the scale, turn it on.

(upbeat music) And I can put this water in here.

I hit the tare button, which means it makes it zero so it knows what it's measuring.

I can add the water (upbeat whimsical music) and we're at 259 grams.

Now I can take this off and I can put my boat on here also.

(upbeat whimsical music continues) Oops, I forgot to tare it.

Zero.

(upbeat music) And it weighs exactly the same amount.

It has the exact same mass.

Because objects that float displace their weight in water, which means the water that came out weighs exactly the same as the object that was pushing down into the water.

And one cool last thing I can show you is we can take the water and we can pour it into this mold.

I built a mold for my boat.

And it sits in here pretty well.

It didn't fit perfectly, but it should work.

Here we go, we're gonna pour this in here and we're gonna see.

It should fill it up almost exactly to the edge.

(upbeat music) Look at that.

I think my table's a little crooked.

But isn't that awesome?

- [Computerized Voice] Isn't that awesome?

- The water that was displaced by the boat weighs exactly as much as the boat with the coins and it fits back into the mold of the boat.

That is buoyancy.

♪ Buoyancy, buh buh buh buoyancy, buoyancy ♪ ♪ Buoyance, buoyancy ♪ Buoyancy is the force that helps things float in water.

Whenever a boat is placed into water, the boat displaces water and it allows it to float.

When a boat sits in water, it pushes the water out of the way.

We call that displacement.

It is placing the water somewhere else since it's using that space.

The water also pushes back up on the boat with an upward force.

If that upward buoyant force is equal to or greater than the weight of the boat, it floats.

While boats can be made of different materials like metal, plastic, or wood, they're shaped to spread the weight over a large area which allows the boat to float.

♪ Buoyancy, buh buh buh buoyancy ♪ ♪ Buoyancy, buh buh buoyancy ♪ Here I have a tennis ball.

Or should we say a tennis boat?

We're gonna put this into the water.

And the question I have for you is, will it sink or will it float?

Let's give it a try.

(upbeat music) Oh, it floats.

Is that what you expected?

I hope so because the inside of this tennis ball is hollow.

The tennis ball starts to sink until it actually starts to float because the buoyant force is pushing upwards.

But what if we take that tennis ball and cut it in half, like this?

What's going to happen now when we place it in the water?

It actually floats.

But do you notice it kind of sits higher up in the water?

And that's because it weighs half of what the tennis ball weighs.

So therefore, it's going to not require as much water being displaced because it's not being pushed down into the water as much.

But what if we take the other half of the tennis ball and we add a sail and a mast, and there's a little bit of weight inside here also?

Let's see what happens here.

Whoa, look how much farther it sinks into the water.

That's because it has more weight.

The tennis ball sinks down until it displaces the same amount of weight it has in the water.

Isn't that cool?

And here, if I apply a little bit of force and add weight to it, I can actually push down and you can see that the water level is going up.

More water is displaced when I apply more force because now there is more weight, so more water is being displaced.

Give this a try.

Have some fun and explore buoyancy with your fish tank and your tennis boats.

- When I say buoyant, you say buoy, buoyant, buoy, buoyant, buoy, buoyant, buoyant, buoyant, buoy.

Buoys have been around since the late 13th century.

Buoys are anchored in the water and help with marine navigation.

They typically mark dangers such as shallow water, submerged structures, or rocks.

These buoyant buoys do a great job preventing boaters from entering unsafe areas.

Watch out for those rocks.

Oh buoy, that could really do some damage.

(metal walls sliding down) (upbeat music) (computer whooshing) - I'm back at the McWane Science Center with my science crew.

And today, we're using foil to see if it can float or sink.

So, what do you guys think?

I have a little piece of foil that's curled up and squeezed together.

Sink or float?

- Sink.

- Float.

- Sink.

- Sink, float.

A couple of sinks, a couple of floats.

Okay, here we go: three, two, one.

It sank.

So that is a piece of metal, the aluminum scrunched together.

And I'm going to challenge you.

Because I have the same piece of aluminum here that is in here but it's sinking.

But I'm going to challenge you to take the same material and build something that's able to float.

All right, so I'm gonna give you a couple minutes to design what you think will work.

And then you're going to be able to test it here in a little bit.

And then when we put it in here later, we're going to put pennies into it to see how many pennies your thing has or can hold before it actually sinks to the bottom of the tank.

You guys ready?

- Yeah.

- Let's get to it.

(computerized waves splashing) (upbeat music) The crew got to work designing their boats and then shared their ideas with another crew member.

(upbeat music) (aluminum foil crinkling) After sharing their ideas, each crew member took their aluminum foil and began shaping their boats.

(aluminum foil crinkling) (upbeat music) Have you tested it?

- I have, it does float.

- It does float?

- Yes.

- And can you apply any pressure to it?

- Mm-hmm.

- Oh, wow, that's a lot of pressure.

- Yeah.

- [Mr.

C] Everyone used the practice ponds to test their boats to see if they would float or sink.

This was going to prepare them for the final test.

(aluminum foil crinkling) (computer generated waves splashing) - Time's up.

Hands off.

It's time to test.

Who wants to go first?

- Here.

- Cole.

Looks like you got volunteered.

All right, come on up.

So I have pennies.

You're gonna place your boat in, and then you are gonna put the pennies in.

'Cause I want no responsibility for what's about to happen.

You think it's gonna hold a lot?

- Yeah.

- Okay.

(upbeat music) And if it sinks, we're just gonna let it sink to the bottom, okay?

All right.

(aluminum foil crinkling) (upbeat music) - I knew that if I had taller walls and the weight of the coins started pushing the boat down, then the walls would make it last longer.

Because water couldn't get in quicker than if the walls were shorter.

(upbeat music) - 50, 51, 52, 53?

53 did it.

- All right.

- 54, all right, so we have a sunken ship.

53 pennies.

Great job, nice job.

Let's give him a round of applause.

(crew applauding) - All right, Camille?

- Yes.

- All right, let's give it a try.

Did yours turn out like you wanted it to?

- Kind of, but I kind of should have made it bigger.

- That's okay.

let's see what it does.

So you think a bigger scale would hold more pennies?

- Yes.

- Okay.

- I think it's gonna sink immediately.

- Well, your prediction- - It's probably right.

- Is incorrect.

- Wait.

- It floats.

Your foil floats, my foil sank.

So it is the way you organize it allows the boat to float.

All right, here we go.

Let's see how many pennies we can get, Camille.

- I had a lot of fun trying to design the boat.

It was kind of trial and error.

'Cause I wanted it to look like my sketch that I had made.

But I didn't really know how to make it exactly like that.

I wanted it to be just a little bit different, but still in a fun way.

- Did you think it was gonna hold this many?

- No.

- I'm impressed, nice job.

(upbeat music) - 12.

- Oh, the 12th one took it under.

All right, round of applause for Camille, nice job.

(crew applauding) All right, Collins?

(computer generated waves splashing) - All right, here we go.

(aluminum foil crinkling) (upbeat music) - One.

If I could change this, I would make it a little bit bigger but the same design.

18, oh.

- I think 17 did it.

- 17.

- All right, another sunken ship, 17.

Nice job, nice job.

(crew applauding) All right, Arjun, let's see what we got.

Now your boat is huge.

Like you didn't condense any of it, right?

- Nope.

- [Mr.

C] All right, you feeling good?

- Yep.

- It floats.

So we all were successful in getting our foil to float.

That's the key.

- Okay.

The reason I picked that design for my boat is 'cause I got inspiration from a cruise ship.

Basically, a cruise ship is like a rectangular and a pointy type of shape in the front.

So that's what I took inspiration from.

And when I made it, it worked very well.

60, 61, 62.

- Oh, oh, oh, oh.

- 63, 64.

- We have water.

- Wait, let's see what it does, let's see what it does.

We have water.

I'm not gonna touch it.

- Do I keep on going?

- Nope, let it go.

Oh, can you see the water?

- Yeah.

- How many was this, 50?

- No, it was 60.

- 60?

- 64.

- 64.

Did you see it collapse?

It was like whoosh.

It just imploded.

That was fantastic.

Give yourselves a round of applause.

That was awesome.

(crew applauding) So we were able to take a piece of foil that was balled up, which sank.

You were able to unravel that, build yourself a boat.

Could you feel the pressure of the water when you would put your finger on it and it's pushing back up?

That's you experiencing buoyancy.

And by designing your boat the way you did, you were successful.

So did you guys have fun?

- Yes.

- Yeah.

I definitely have some ideas watching you build yours.

I think I should also give that a try.

So I have one question to ask you.

What time is it?

- Science time.

- Orange you glad we get to do science together?

An unpeeled orange floats due to air trapped inside its rind.

The rind acts like a life jacket, reducing the orange's overall density and allows it to float.

However, a peeled orange sinks because it is denser than water.

When the rind is removed, only the denser fruit is left behind causing it to sink.

These oranges really make floating seem appealing.

- Come here.

Check this out.

This is a rice contraption.

This allows us to take grains of rice that are stacked on one another.

And it looks just like a solid, right?

Boom, boom, boom, boom, boom.

But what we're going to do is we're gonna take this motor that I've attached here on the bottom and we're going to turn it on and it's going to spin.

And the way I set this up is that this little piece of wood is sticking really far out.

And that wood is going to cause it to vibrate because the motor's no longer balanced.

That vibration will put these grains of rice into motion.

And hopefully, we have a liquid- - [Computerized Voice] Or a fluid.

- to explore buoyancy with.

Are you ready?

Let's give it a try.

So we're gonna take a ping pong ball and we're gonna stick a ping pong ball down into the rice.

And we're gonna stick a ping pong ball up here on the rice.

And then we're gonna take a glass marble, put it on the rice.

And we're gonna take a glass, oops, a steel bearing and put it up here on the rice as well.

None of them are currently moving, right?

Let's find out what happens when we turn our motor on.

Here we go in three, two, one.

(motor whirring) (Mr.

C laughs) Look at that.

(motor continues whirring) That is amazing.

Did you see the steel bearing?

It just sank going, whoosh.

It went straight down into our fluid.

When that was turned on, it was acting like a fluid.

So it was more dense than the rice, and it caused it to fall down.

And our ping pong ball, which was down in the rice, was now being pushed up by the rice that was acting like a fluid.

It's sort of like at the start of the show when I was throwing things into the tank.

Some things sank, some things floated.

And that's what's happening here.

And back here, our glass marble, it's like halfway in the water, or halfway in the rice and halfway out, and it's just kind of floating midway.

So you too can build one of these amazing rice contraptions to explore buoyancy.

Ooh, that thing went down there good.

You can explore buoyancy in your house using rice as a fluid.

That's crazy.

That's so cool.

Let's try it again.

All right, so I have two ping pong balls up there now.

And I have a steel bearing and a glass marble back here.

Now when I turn this on, pay attention not just to the objects, how they move around, but to the rice that's moving around like a fluid.

In three, two, one.

(motor whirring) Wow, that came up fast that time.

Where's our other ping pong ball?

Where are you, buddy?

There it comes.

Oooh.

(motor continues whirring) And they float.

Build one, have some fun exploring fluids and buoyancy with grains of rice.

(motor continues whirring) That's pretty nice.

- Let's dive into it and build a Cartesian diver.

Grab some ketchup packets from a local fast food restaurant and toss them into a bowl of water.

Find one that floats on the water.

This is going to become your diver.

Now take an empty plastic water or soda bottle, push your ketchup packet into the bottle and fill it to the top (upbeat music) and seal the lid.

(upbeat music continues) Now squeeze the bottle and observe the packet.

I didn't expect that.

It sinks.

Inside the ketchup packet is a tiny pocket of air.

When you squeeze the bottle, you increase the pressure on the ketchup packet.

This increase in pressure causes that little air pocket to get smaller, sending the packet on a deep dive down.

When you release the bottle, the packet floats back to the top because the air bubbles have less pressure on it and now can expand.

This makes the packet less dense than the water, making it float again.

Try it with different condiments to see which one works best.

- This story is about three balloons filled with helium.

This first little balloon, when let go, floated away.

That's because that balloon and that string are less dense than the surrounding air, which is a fluid.

That fluid pushes the balloon upwards and it causes it to rise because that balloon is less dense than the air in the room.

This little red balloon was tied to a piece of PVC pipe.

And when let go, the balloon fell because the balloon and the PVC pipe were more dense than the fluid in the room.

Therefore, it has a negative buoyancy.

This one has a positive buoyancy.

But my blue balloon right here, my little friend, little blue balloon, when I let this balloon go, I will extend you out here, this balloon is neutrally buoyant.

It doesn't sink or float.

But because of the static in the room, it's attracted to everywhere I move or everywhere I go.

And this is neutrally buoyant.

I love you too, buddy.

So blow up some balloons, have some fun.

And remember: positive, negative, and neutrally buoyant.

(balloon squeaking) (Mr.

C laughing) (upbeat music) Whee.

- There's nothing better than jumping into a pool on a hot summer's day.

The water cools you off, but it also pushes you upwards.

People float in water because the human body is slightly less dense than the pool water, allowing a buoyant upward force to exceed the downward pull of gravity.

An object floats when its weight is less than or equal to the weight of the water it displaces.

Splish splash, we are having a blast.

- Ahoy, maties.

♪ Today, we sailed the seven seas ♪ ♪ Aluminum boats, they held pennies ♪ ♪ Learning all about buoyancy ♪ ♪ Having fun with Mr.

C ♪ Wow, what an amazing day learning together.

I took all this information down in our notebook so we could do it all again.

If you built an aluminum boat, what would you do differently to hold more pennies?

Do you think anything other than a ketchup packet would work as a Cartesian diver?

I relish the thought of trying that variable.

We've done so many great experiments today.

Float some ideas to your crew and see what you wanna try.

You know, I was thinking.

I saw some rubber gaskets online.

I wonder if those could double as pool floaties.

Hmmm.

(computer whooshing) - Float away, little balloon.

Whee.

(laughing) So much fun talking about buoyancy today: positive buoyancy, neutral buoyancy.

Most importantly, boy oh buoyancy, have we had a lot of fun today?

Make sure you hop online and download your "DIY Science Time Notebook" so you can keep track of all the cool things you've been talking about.

And boy oh boy, oh buoyancy, did we have fun?

And I'm sure you can keep track of some really cool experiments.

Here's the deal.

Today was awesome.

Today was fun.

I want you to keep learning.

I want you to keep exploring.

I want you to keep having fun.

And I want you to remember that science and buoyancy is wherever you are.

So, go make yourself a rice contraption that can take objects and make 'em float in the rice.

One more time, this is so cool.

Here we go, buoyancy.

(motor whirring) (Mr.

C laughing) Rise, my ping pong balls, rise.

(audience cheering) That is so cool.

See ya.

♪ We're talking positive and negative buoyancy ♪ ♪ And also neutral neutral buoyancy ♪ I found another steel marble.

And let's see how it behaves in the water.

Whoa, (laughs), it sank.

It's the static is insane.

It's chasing me.

♪ It's so much fun ♪ - With my buoyancy superpowers.

Why am I looking at the microphone when I'm talking?

I'm looking at the microphone while I'm talking.

(Mr.

C laughing)