Buoyancy is the scientific principle that explains why some objects float on water while others sink. Objects that are less dense than water, such as dry wood with tiny air holes, float because the water pushes them upward. Conversely, dense objects like rocks sink because they are heavier than the water they displace. This principle allows us to build rafts by tying multiple dry logs together, creating a stable platform that can carry heavy loads across water.
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🐰🐤Roro, Dodo & Kiki: River Rafting with Chacha the Panda追加:
Good morning, everyone.
Let's play.
Let's go swimming.
>> [music] >> Good morning. Hi, Roro, Dodo.
Hi, everyone. Wait for me. Cece.
Good morning.
Quack. Hmm. Meow. Squeak.
Tweet. Tweet. Tweet. Tra la la.
Tweet.
The stream is so beautiful this morning.
Quack. Yes, it is. Purr. And so peaceful.
>> The sun shines brightly on the stream.
A perfect place to start our adventure.
The morning is so peaceful here by the stream.
Yes, it truly is.
>> [music] >> All right. Now we're ready for our adventure.
Good morning, my wonderful friends.
Today is a beautiful day for science and helping others.
Squeak.
Quack, quack. This stream is so lovely, quack.
Quack.
Quack.
Happy.
Quack.
Quack.
Oh, these feathers needed a good fluff.
Quack.
>> [laughter] >> Quack, quack. This is amazing. Quack.
Good morning, friends. Let's start our tiny forest adventure.
Quack, quack, quack.
Good morning, Dodo. Good morning, Roro.
How are you?
Good morning, Kiki.
>> [laughter] >> My tummy is waking up. It is making a hungry song. Rumble, rumble. I want to find a yummy summer breakfast.
>> [music] >> I see something.
Mhm.
Let's go investigate.
Meow.
Good morning.
The wind smells like fresh water and sweet green leaves.
Mhm. And the sun is so warm on my fur.
>> It is a very good morning.
>> Did you hear that? I heard it, too.
Let's see who it is.
Oh, my tummy is still hungry.
Quack. Is that a walking bush?
>> Hmm?
>> Ah, so tired.
Who are you?
Hmm.
That hit the spot. Yawn.
Content sigh.
Hmm. So full.
Oh, my tummy is so full.
I need to rest.
>> You got this, ChaCha. We're here for you.
Let's go.
You can do it.
>> Hello, Dodo.
Hello, Roro.
Hello, Kiki.
>> Good morning.
It is nice to see you here today.
I am looking for breakfast.
What? how fast I can run.
>> That was very fast, Cece.
>> Look, they're here. We can start the adventure.
>> Squeak, squeak.
>> Wee, woo.
>> [screaming] >> Wee, look at me go.
>> Slow down, you'll make me tired just watching.
>> Look, over here. I see them.
>> Squeak.
>> Hello everyone.
>> All right team, there it is.
>> Wow.
>> Intriguing.
>> It is a great day for swimming.
The sparkling stream is full of water today.
>> You're doing great, keep going.
>> Good morning, ChaCha.
>> Good morning, Cece.
>> It is nice to see you both.
>> Quack, quack.
>> [laughter] >> Meow.
Quack quack. Squeak.
Meow.
We are looking for breakfast, too.
That's great. Let's start over here by the rocks.
Quack.
What do pandas eat for breakfast, Cha-Cha?
You look so fast. We're really fast. And so cute.
Look at us swim.
>> I love to eat bamboo.
>> Sweet, green, crunchy bamboo shoots.
>> [laughter] >> But I have a big problem today.
>> A problem?
Hm, Cece, I think I need a short nap.
>> But Cha-Cha, the water looks so fun.
Let's explore.
>> I feel so sleepy.
My tummy hurts a little.
>> No, Kiki. I ate all the bamboo on this side of the stream yesterday.
>> Wee, look how fast I can go.
>> [laughter] >> Look, the sparkling stream.
Look over there.
What is it?
Let's go and check.
>> [snorts] >> Look, over there.
What is it?
Let's go see.
Oh my, wow.
Wow, those look very crunchy.
They are the best bamboo shoots in the tiny forest.
My tummy wants them very much.
But they are on the other side of the stream.
>> Meow.
>> Meow.
>> That is not a big problem.
We can just walk across the water.
>> We can?
>> No.
I'm too late. What do I do now?
>> Let's cross the stream.
>> Quack, yes.
>> Careful, friends.
>> No, we cannot. Look at the stream today.
I'm worried about how fast it's moving.
This water looks really strong. We need to be careful. The stream sounds louder here.
>> Woohoo, water.
It's moving so fast.
>> Let's be careful.
>> Oh, Dodo, I'm scared.
>> Don't worry, Roro. I'm here. Everything will be okay.
>> Quack, the water is running away very fast. Don't worry, we can figure this out. Just stay behind me.
>> The water current is very strong today.
>> Look, there's the stream.
>> Let's go swimming. Be careful of the current.
>> Cece, she's fast.
>> I can swim in the fast water.
>> We know you can, Cece. Go for it.
>> I am an otter. I love fast water.
Wee!
Look at me go!
Watch this.
Hee hee hee.
Wee! I love the water. I'm all dry now.
Let's play.
>> Can you swim across and bring the bamboo to Cha-Cha?
>> I'll get it, Roro.
>> Hmm, so full. Just hmm, a little nap?
>> I can swim across.
But, bamboo shoots are very heavy.
I have little paws.
I cannot hold the heavy bamboo and swim in the fast water at the same time.
>> The stream is moving fast. How do we cross?
>> Maybe we can hop over.
>> Be careful, friends.
>> Cece can help us. Watch.
>> The water is too fast.
>> Oh, my tummy hurts. It's so big.
I cannot swim.
My tummy is too heavy.
If I jump in, I will sink like a big round rock.
I will never get my yummy breakfast.
Don't be sad, Cha Cha. We're here to help. I don't think I can do it.
Do not be sad, Cha Cha.
I'll lead the way.
The trees here are so strong and tall.
They watch over us.
Hm?
Yes.
That's it.
Do not worry, Cha Cha. We are best friends.
Squeak.
Purr. Quack.
We will help you get your breakfast.
We cannot across.
And the water is too fast to walk.
But we will use logic.
We will use science.
We will build a machine to travel on top of the water.
>> [laughter] >> A machine?
A machine?
>> Quack, quack.
>> Oh, hello.
>> Quack, will we build a flying water car?
>> The morning sun is bright.
Let's go.
Perfect.
>> Meow.
Water and science go very well together.
>> We will learn about the science of buoyancy.
>> Quack.
>> Meow.
>> Squeak.
>> We will build a raft.
>> Let's gather.
>> Wattles over, walks gracefully, moves energetically. We are here.
>> Together, we can find it.
>> Quack, quack.
>> Meow.
>> We need to stay together.
>> Purr.
>> Quack.
>> Okay, let's go.
>> To build a raft, we must first understand the fundamental principles of buoyancy.
Buoyancy is why some things float on the water.
And and some things sink to the bottom.
Huh.
Hmm. Why is my tummy so round? It wasn't like this yesterday.
Quack.
Does my tummy have buoyancy?
I knew we could do it.
Let us do a science test.
Roro, please push that rock into the water. Waddles over. Grunts. Cheerful quack. Ah. That's it. Hmm. That's a big rock, but together we can move it.
Quack. Push. Quack. Quack. Done.
Quack.
Look, the rock disappeared. So fast and so sleepy.
Oh, no.
The rock is sleeping under the water.
It has no buoyancy.
Oh, dear.
Let's try putting it over there.
Quack. Good idea.
Kiki, please put that dry stick into the water.
>> Meow.
>> That's right, Kiki. Just like that.
The water rushes quickly here.
>> Meow.
>> Purr.
>> Meow.
Meow.
The stick is floating.
>> Ah.
>> It's working. We did it.
>> Hooray!
>> Yes.
>> Exactly. The rock is very dense and heavy, so it sinks.
Density determines how things behave in water.
But dry wood is full of tiny air holes.
It is less dense than the water.
The water pushes it up.
Wow.
Science is very smart.
>> I've got a great plan in mind.
So, if we tie many dry logs together, we can build a raft to cross the water.
>> Wow!
>> Are you all ready to try it?
>> [laughter] >> The water will push them all up and they can carry heavy things, even a chubby panda.
>> Quack.
>> Purrs.
>> Together, we can do it.
>> Yes, let's go.
>> Hooray!
>> [screaming] >> Team, we have a new mission.
>> We need to find dry, light wood here on the ground.
We also need long, strong vines to tie the wood together.
>> [laughter] >> I can do it.
Choose me, please. I can do it.
>> Squeak.
>> I will find the best wood in the water.
>> Let's do it, Cece. I'm ready to swim.
>> Wait, dive time. Yahoo!
>> Wow!
>> I'm going to find it. Let's go.
>> [music] >> Meow.
These vines are very strong. They will not break.
Hmm, a big dry log. Just what I needed.
This is a very good log.
>> I I can do this.
>> I can do it. Just a little further.
>> [snorts] >> Keep rolling.
>> Quack. I will help you, ChaCha. I am very strong. Mhm. Thank you, RoRo.
Quack. Quack.
>> We >> All right, friends. We have the logs and the vines.
>> Perfect, Dodo. This looks like enough. I think we should start with the big one.
>> Mhm. Bamboo. Let's do it.
>> We must put the logs side by side.
>> Wow.
>> If we build it right, we can cross safely.
If the raft is wide, it will not flip over in the fast water.
>> Almost there. KEEP PUSHING.
WE'VE GOT THIS. JUST A LITTLE FURTHER.
KIKI, we need your precision to tie the knots.
>> Mhm.
We need your precision.
Meow, I am ready.
Oof.
Pull. The knots are perfect. Squeak.
The raft looks beautiful. It looks like a big wooden bed.
>> Mhm.
A wooden bed?
Can I take a nap on it?
>> No sleeping yet, ChaCha. We have to get your yummy breakfast first.
>> Now, we must test our machine. 1 2 3 push.
>> Quack.
>> Meow.
>> Push.
>> Keep pushing, friends. We're almost there.
>> Whee.
>> Almost in the water.
>> Watch the edge. So tired, but we can do it.
>> Hooray. [screaming] Buoyancy wins.
>> It is very stable. ChaCha, it is your turn. Step carefully.
>> Okay, Dodo. I am coming.
>> I am standing on the water. I am not sinking.
>> We are all on the boat.
So exciting.
Ready for our adventure.
>> [laughter] >> Quack. We are turning around and around.
I am getting dizzy. Meow. Big rock on the right.
Look out.
Quack, quack.
We're going too fast. Push harder.
Watch out for that rock. ALMOST THERE.
WE'RE DOING IT. Keep pushing. The current is strong.
We made it. Yes.
>> Hooray.
>> Let's go this way. Mhm, bamboo. All right, everyone. We're here. Woohoo. We made it. Let's explore. Just a little rest first. Look at all the bamboo.
>> It is the best breakfast in the whole tiny forest.
>> Patuwi, it is too hard.
I need sweet summer berries.
>> Meow. Do not worry, Roro. I see a big bush of sweet red berries right over there.
>> Ah, yes. Berries.
>> Today was a great victory for science and friendship.
>> We did it.
>> Hooray.
>> Look at all this bamboo. We're ready to go.
Look at the water go. We're almost home.
>> So fast.
>> [snorts] >> Tomorrow is another wonderful day for science.
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