Heat moves from warmer to cooler places — Physics, 7–10 years
Heat is always on the move when two things have different temperatures. This explains why a hot drink cools and why a warm coat helps your body lose heat more slowly.
Heat spreads out
Heat is energy moving from a warmer thing to a cooler thing. It may travel through a metal spoon, through moving air, or by invisible rays from the Sun. The movement continues until the temperatures become closer.
Why does a hot drink cool?
People needed to understand why food cooled, rooms warmed, and ice melted. The useful rule is not that cold travels into hot things: heat leaves the warmer object and enters cooler surroundings. This helps us choose materials that keep heat in or let it out.
A mug of tea
A mug of tea is at 80 °C, while the room is at 20 °C. First, heat leaves the tea and warms the mug, the air and the table. Next, the tea temperature falls: 80 °C, then perhaps 60 °C, then 40 °C. It stops falling when it reaches about 20 °C.
Cold is not a substance
It is natural to say that cold enters your hand when you hold an ice cube, because your hand feels colder. But what actually happens is that heat moves from your warmer hand into the colder ice. Your hand loses energy, so its temperature drops.
Keeping heat where it belongs
A thermos has layers that slow heat moving in or out, so soup stays warm and water stays cool for longer. A house uses insulation in its roof and walls for the same reason. These materials do not create heat; they reduce its escape.
Keep exploring
Other languages
Loading MyLeoNes™…