| Answer | Crossword Clue |
|---|---|
| AIR | Balloonists' heat this |
| radiation | The energy transmitted in this way, as heat, light, electricity, etc |
| radiations | The energy transmitted in this way, as heat, light, electricity, etc |
| conductors | A material or device that conducts or transmits heat, electricity, or sound, esp. when regarded in terms of its capacity to do this |
