* Density: Density is a measure of how much mass is packed into a given volume. A denser object has more mass squeezed into the same space.
* Buoyancy: Buoyancy is the upward force exerted by a fluid (like water) on an object submerged in it. This force is equal to the weight of the fluid displaced by the object.
Here's the connection:
* Rocks denser than water: If a rock's density is higher than the density of water, it will sink. This is because the weight of the rock (due to its density) is greater than the buoyant force pushing it upwards.
* Rocks less dense than water: If a rock's density is lower than the density of water, it will float. This is because the buoyant force pushing upwards is greater than the weight of the rock.
Example:
* Granite: Granite is a dense rock, typically sinking in water.
* Pumice: Pumice is a volcanic rock with many air pockets, making it less dense than water. This allows pumice to float.
Key takeaway: A rock's density directly determines whether it floats or sinks in water. The denser the rock, the more likely it is to sink.
