... Convection in a pot. ... A primer on convection Stars do it, icy moons do it, even pots of coffee do it. ... Lava Lamps to Lava Flows . ... Stars and planets use this kind of cycle to get heat from the inside out. ... In medium-sized stars like the Sun, radiation transports heat deep within the star, where it's hottest (see Figure 3), and convection operates toward the outside, where it's cooler. In small, cool stars, convection is the main mechanism; in large, hot stars, radiation dominates. ...