Insulation is material that slows down the movement of heat, cold, sound, or electricity. Think of a winter coat: the puffy material inside traps air and keeps your body heat from escaping into the cold air around you. That's insulation at work.

Buildings use insulation in their walls, attics, and floors to keep warm air inside during winter and hot air outside during summer. Without insulation, a house would lose heat quickly in cold weather, making the furnace work constantly and wasting energy. Good insulation makes homes more comfortable and costs less to heat and cool.

Insulation works by creating barriers. Fiberglass insulation uses tiny glass fibers to trap air, foam insulation uses bubbles, and even simple materials like newspaper or straw can insulate when layered properly.

Electrical wires have rubber or plastic insulation covering them to prevent electricity from escaping and causing shocks. A thermos bottle uses insulation between its double walls to keep hot drinks hot and cold drinks cold. Whenever you need to keep something separated from its surroundings, whether it's heat, cold, sound, or electricity, insulation does the job.