The movement of material due to differences in density that are cause by differences in temperature is called convection. This is usually displayed by water or air. We can observe this in one of our daily things that we do to keep us alive, cooking, specifically boiling water. Boiling water has many uses in our daily life and convection allows us to do so. When the container is heated through conduction, the water right above it becomes hotter and eventually rises up to the surface. In turn, the cooler water sinks down and takes the place of the heated ones. This creates a movement that transfers heat and this is called convection.