Bill Nye: Buoyancy And Displacement Notes
- To "Displace" Water means to have an object raise the level of the water by the volume of the object
- A ball and a ship that are made of the same amount of the same material will not both float, this is because the ball has less surface area so the weight is not spread out over a larger area, so it sinks, the ship spreads out it weight over it's large shape, so it floats
- Remember, things displace as much water as they weigh
- The famous Greek mathematician and physicist Archimedes discovered (in the bathtub) that he could find the volume of an object by measuring the amount of water that it displaced (see picture at left)
- Fish can control their buoyancy by using their swim bladders. when they fill them with air that is sorted through their gills, they rise to the surface. This is how scuba divers rise and sink with their air tanks
- Negatively Buoyant: Object sinks (denser than water)
- Positively Buoyant : The Object floats (less dense than water)
- Neutrally Buoyant: The object is suspended in the middle (neither floats nor sinks)