I hope you caught our experiments on Buoyancy today. If not catch up here with our staged experiment
Today we had a "Eureka" moment when we realized that different weights don't necessarily dictate whether something will sink or swim.
Our experiment showed that a heavy ball sinks to the bottom and displaces a large amount of water; forcing the water level to rise. When a lighter ball floats on the surface it doesn`t displace much water and therefore floats.
This shows us that the important weight is the weight of water that is displaced.
If an object displaces a large volume of water that weighs a lot then the object will sink.
If only a little water is displaced then the object will float.
Sometimes we need to build heavy items to float or a ship to carry heavy items, so we need to design them differently.
In our experiment we spread the weight over a larger surface area by creating a "boat" from aluminium foil, the heavy ball no longer sinks.
The same method is used to build huge ships, they are hollow full of air and the surface area that touches the water is big to spread the load over a larger area. This displaces less water resulting in a heavy boat that floats.