“How can we have convection occur without having to input any energy?”
Heat can be transferred in a fluid medium using convection. An easy way to induce this is to use a power source to move some mechanical equipment, whether it be a fan or a pump. However, can convection occur without any external input? Well, let’s use our engineering mindset to solve this problem. We know that if we heat up a fluid, then its molecules will move around faster. And if molecules move around faster in a gas, then the gas will become less dense. And if one region of a gas is less dense than another, part of that gas will move in to cover it. This way, we can create what scientists and engineers call Natural Convection. Natural Convection is the main mechanism behind everyday phenomena such as air circulation and radiators.