Book 1, Question 109 · Video
Why Do Boats Float? The Secret of Buoyancy!
A giant steel ship can float while a small rock sinks, and it is all about pushing water aside. Water pushes up on things, and that push is called buoyancy. A boat pushes a lot of
Read the full answer →What Crafty Clover says in this video
Intro
Hi! I'm Crafty Clover! Let's discover something amazing. Why do boats float?
The Big Idea
Giant steel ships can weigh more than a thousand elephants. So how do they float? The secret is a push from the water itself, and a clever hollow shape! Let's see how it works, step by step!
Water Pushes Up: That Is Buoyancy
Step one: water pushes up. That upward push is called buoyancy. Anything in water gets pushed up, even a rock. That's why things feel lighter underwater!
A Boat Pushes a Lot of Water Aside
Step two: a boat pushes a lot of water aside. A boat shoves water out of the way. Scientists call that displacing water. The more water it pushes aside, the bigger the upward push it gets back!
If the Push Can Match the Weight, It Floats
Step three: if the upward push can match the weight, it floats. It's like a tug of war, between the boat's weight pulling down, and the water pushing up. If the water can push up as hard as the boat weighs, the boat floats! If not, it sinks.
Boat Hull vs a Rock
Let's compare a boat hull and a rock! The wide, hollow hull pushes aside lots of water. That's a big upward push! The small, solid rock pushes aside only a little water. The push isn't enough. Down it sinks!
Quick Facts
Quick facts! Steel ships float because the hull is a big hollow shape, filled mostly with air. More hollow space means more water pushed aside, and a bigger upward push! A Greek thinker named Archimedes figured this out over 2,000 years ago. And salty ocean water pushes up harder than fresh water.
Think Like a Scientist
Now, think like a scientist! Drop a ball of clay into a bowl of water. It sinks! Now shape the same clay into a little bowl, and set it on the water. It floats! Why? The bowl shape pushes aside more water. How many pennies can your clay boat carry?
Outro
Boats float because water pushes up, and a big hollow hull pushes aside enough water to hold the boat up. Stay afloat, explorers! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!