Usually, when people think radiation, they think nukes, mutants, Chernobyl. Hot things glow, giving off light that carries the heat away. That's why the Sun shines and warms the Earth. It's also why you feel hot when sitting in front of a fireplace or electric heater. The desert is so cold at night because you and the air around you are glowing in the infrared, losing heat to outer space.
Convection is the third way that heat can move.
Instead of molecular domino-effects or streaming heat rays, convection relies on movement of fluid. When hot fluid moves, it carries the heat along with it. You can think of the three ways heat moves in terms of passing a love note to your sweetie across a classroom. Convection is a last-ditch way to get rid of heat. It takes effort to start convection, so heat usually prefers to escape by conduction or radiation.