Buoyant Boats
Students conduct a simple experiment to see how the water level changes in a beaker when a lump of clay sinks in the water and when the same lump of clay is shaped into a bowl that floats in the water. They notice that the floating clay displaces more water than the sinking clay does, perhaps a surprising result. Then they determine the mass of water that is displaced when the clay floats in the water. A comparison of this mass to the mass of the clay itself reveals that they are approximately the same.
Archimedes was a great mathematician and scientist who was born in 287 BC. It is said that while taking a bath one day, he got the idea for using the displacement of water to compare the densities of objects. In particular, he was able to use this method to determine that a crown made for the king did not contain the full amount of gold that it should have.Copyright Sandia National Laboratories http://www.sandia.gov/tp/SAFE_RAM/AP.HTM
When designing boats and ships, engineers must determine the total amount of water displaced when. They also apply the same concept when designing waterways in order to determine the maximum sized boat that can pass through a human-made waterway such as the Panama Canal.
- Students will be able to describe a means to make a material that is denser than water (modeling clay) float.
- Students will be able to describe the parallels between the design process used to create a dense but floatable object, and the scientific method of inquiry.