[Music] have you ever really watched a pot of water start to boil the bubbles tend to come we have a heat source first and their paths are sort of Wiggly maybe you even notice the motion at the surface is turbulent and spreads out from certain points if you've seen this movement you've seen convection convection is the heat transfer due to bulk movement of fluids near the heat source water is warmed rises to the top and then cools at the surface and sinks to the bottom convection is driven by differences in density due to temperature changes warmer less dense material is rising and cooler more dense material is sinking under the influence of gravity convection doesn't just happen in pots of water either in our atmosphere there are large convection cells called Hadley cells because of the angle of earth's tilt and position with the Sun the equator receives a much more consistent heat from the Sun in the polar regions the warmed air rises from the equator regions moves toward the poles cools then sinks back to the Earth's surface warm air also rises at the 30-degree latitudes which cool at the poles convection also occurs in the oceans again large amounts of warming occurs at the equator then the water moves toward the poles which are much cooler as water cools they're continuously moved until they're back at the equator to be warmed again scientists also hypothesized that the mantle of Earth itself is convecting the interior of Earth is very hot and magma moves toward Earth's surface cools and then sinks toward the center this mantle convection is the proposed driving force for plate tectonics where magma rises we should see spreading rifts or hot spots where Bama Falls it can pull the continents with it creating subduction zones mountains and even volcanoes thanks for watching this episode of teacher's pet don't forget to Like and subscribe and follow me on Twitter at science pet