How does convection of heat take place in liquids and gases?

Answer 1

The molecules get heated up ,gain energy and move to a new location thus transmitting heat from one part of the liquid to another.Similar things occur in gases.

In the place being heated, the particles move more quickly because the heat energy is converted into kinetic energy in the particles. Faster moving particles collide more often and with more force and so they spread out, becoming less dense. Less dense fluids float on denser fluids so the heated particles start to rise. This has two effects. Firstly, denser, colder liquid cones in to replace the risen fluid, which can also be heated and rise. Also, the hotter, risen and more energetic particles start to transfer some of their energy to the colder fluid around them. This sets up a CONVECTION CURRENT of fluid rising where it is heated, spreading out at the top and falling back down in the colder parts of the fluid. and moving along the bottom to replace the rising warmed fluid. This carries the heat to the whole of the fluid.