Question

Ice is a solid though it floats on water.why?

Answer 1

Floating and sinking is determined by Archemedes principle. When a body is dropped in a liquid, it floats if the weight of liquid displaced is equal to the weight of solid. We call it a condition where the weight of body is balanced by buoyant force.

An easy way to determine if a substance floats or sinks in a liquid is by knowing density. Density = mass / volume. Density of water is 1000kg/m^3.

Ice has density of 916.7kg/m^3. So, ice will float in water. But materials like iron ,steel etc have density of 7000-8000. So they sink in water.

So, generally, a substance floats, if its density is lower than the liquid, and sinks if density is high.

If you want to know more physics in the process of floating and sinking, you need to understand force balance and how buoyant force is formed. Buoyant force is equal to weight of liquid displaced, weight is equal to density of liquid multiplied with volume.