If you’ve ever been to the beach on a hot summer’s day, you’ll know that there is almost always a nice, cooling breeze coming off the water and into land. What makes this effect happen?
Specific Heat Capacity – The specific heat capacity of any material is the amount of heat energy it takes to change the temperature of that material. For example, if you put equal amounts of 2 different materials into the same flame, and they have different heat capacities, one of them will heat up faster than the other. Water has a higher specific heat capacity than land and therefore on the same day with the same hot sun shining down, the land will heat up faster than the water.
High and Low Pressure – Because the land on the coast will heat up faster than the sea next to it, the air over the land expands and rises faster. As the warm air moves up, it leaves behind an area of low air pressure, and wherever there is low pressure, air will flow towards the area, creating wind.
So hot land means hot air, which rises, while cooler air over the sea moves in to fill the space. Of course, as the cool sea air moves towards the land under higher pressure, the air high above the sea is pulled down to fill its place. And then the warm air that rose up over land pushes out to fill the place of the air moving down over the sea.
This keeps a cycle of sea breeze running throughout the day while the sunshine heats up land faster than water.
Find out more about ocean currents!