Buoyancy
When something goes in water, water is displaced equal to whatever it weighs. When you displace water, your just pushing the water out of the way.
Archimedes, a Greek mathematician, found out that you can find the buoyant force of an object by placing it in water and then the displaced water of the weight is the answer. He found this out when he put himself down into a bath tub with water. He realized that the water rose and he realized it's how you can find volumes of objects
Fish can control their buoyancy because they have swim bladders. It's an organ inside fish that contains air so that fish can control how much air is in it so that they can control what depth in water they want to go to.
Negatively Buoyant: It's when something sinks in water
Positively Buoyant: It's when something floats on water
Neutrally Buoyant: When something does not sink nor float in water.
Positively Buoyant: It's when something floats on water
Neutrally Buoyant: When something does not sink nor float in water.