Imagine you want to make chocolate candy for Valentine's Day. You try to melt chocolate in a pan. Suddenly, it starts burning! Now the chocolate is overcooked. Is there a better way to melt it? You can use a double boiler. A double boiler is easy to make and use. You only need a pot, a bowl, and water. First, pour the water into the pot and set the bowl over the water. Next, put some chocolate in the bowl. Then place the pot on the stove and set the heat to a low temperature. The chocolate melts nicely as the water boils slowly. How does the double boiler work? As the water boils, the hotter water molecules move up and the cooler ones move down. Then, the cooler molecules heat up and rise again. As this happens over and over, the temperature rises. This process is called "convection." During convection, steam from the boiling water heats the whole bowl. This makes the chocolate melt evenly. Now, you can melt chocolate nicely. Let's make delicious chocolate candy!