Heating is the process of making something warmer by adding thermal energy to it. When you turn on a furnace in winter, you're heating your house. When you microwave a bowl of soup, you're heating it until it's hot enough to eat.

Most homes use a heating system that warms air or water and distributes that warmth throughout the building. Some systems burn natural gas or oil to create heat, while others use electricity. The heated air flows through vents, or hot water moves through radiators, raising the temperature of each room. Before modern heating systems, people relied on fireplaces and wood stoves, which meant constantly gathering fuel and tending the fire.

The word also describes what happens when something gets hot through friction or energy. When you rub your hands together quickly, the friction creates heat that warms them up. A computer's processor generates heat while it works, which is why computers need cooling fans.

Scientists measure heating in units of energy like joules or calories. When they talk about heating up a substance, they mean increasing its temperature by adding energy to its molecules, making them move faster. That's why hot things feel active and energetic, while cold things feel still and sluggish.