How does heat move?

Heat transfer: q = h × A × ΔT. Heat always flows from hotter to colder, and it travels in just three ways: by touch through solids (conduction), carried along by moving air or water (convection), and as invisible infrared light (radiation).

Read how it works: How does heat move? · The history of heat transfer · More boxes on Glassbox

Chapters in this interactive model

1. Heat moves three ways: touch, flow and glow: A rod, a pot and a tawa on one bench: conduction, convection and radiation, each measured in watts.
2. A spoon in chai and chips in hot air: Why a steel spoon stays cool but a silver one burns, and why a fan cooks chips faster than an oven.
3. Insulation: slowing heat down: A fridge wall keeps the kitchen's heat out; a geyser's foam keeps its heat in. Neither can stop it, only slow it.
4. Fins and breezes: getting rid of heat: A motorbike engine grows fins, and your body sweats. Both are tricks to make q = h A ΔT bigger.
5. When heat goes in and nothing warms up: Melting and boiling hold the temperature still, a flask blocks all three routes, and metal only feels colder.