Idea 5of 9Builds onEnergy on the move
Across empty space
A glowing heater warms your face. Through what?
Today you'll discover
- how energy crosses a gap with nothing in it
- why the Sun can warm Earth across empty space
- the name for energy carried as light
Think firstA heater glows across the room; your face warms
A heater glows across the room. Your face warms while the air between barely does. How?
Decide first, then press Next. Watch the rays cross the gap where nothing else can.
A glowing heater on the left and a hand on the right with a clear gap between them. After a prediction, rays are drawn leaving the hot surface, then crossing the empty gap, then arriving at the hand, and the way of travelling is named. The last step asks how the Sun can warm Earth across empty space.
See the whole ideathe big idea and the key word, in one place
The big idea
Radiation: energy carried as light, needing nothing to cross.
Compare themThree ways to move thermal energy: handed along through a solid, carried round in a fluid, or sent across a gap as light. A campfire does all three at once.
Key word
- radiation
- the transfer of energy as electromagnetic waves, light visible and invisible, needing no material to travel through
About this modelParticles are drawn far apart and the arrows show energy, not matter, except in the convection loop where the fluid itself moves.
Particles are drawn far apart and the arrows show energy, not matter, except in the convection loop where the fluid itself moves.
Ready to use it?
- Name which way energy is travelling in a described situation, and say what it needs to travel.