Boats are big, heavy objects—so how do they stay on top of the water instead of sinking? It all has to do with buoyancy!
Buoyancy is a force that pushes things up in water. If the force pushing up is stronger than the weight of the boat, the boat will float. That’s why even big ships can stay on the water without sinking.
The shape of the boat matters too. Boats are usually hollow and wide on the bottom. This spreads out their weight and helps them stay balanced. That’s called displacement—it’s how much water the boat pushes out of the way. If a boat pushes out enough water, it will float!
Boats can be made of metal, wood, plastic, and even paper. What matters most is their shape and weight—not what they’re made of.
Some boats are tiny like canoes. Others are giant like cruise ships. But they all float because of buoyancy and displacement.
Did You Know?
A boat made of steel can float, but a ball of steel the same weight would sink!
🧠 Your Boat STEM Challenge:
Design a boat that floats or holds the most objects. Try using supplies from your STEM Boxes. How many pennies or cubes can it hold before it sinks?
