Heat put to work
A room heater glows red. A phone charger only feels warm.
Loading lab…
The rule
Heaters, irons and kettles use the heating effect on purpose. Each has a heating element. This is a coil or rod of wire that gets hot. A coil is wire wound round and round.
Heating elements are often made of nichrome. For the same current, nichrome gets hotter than copper. Nichrome has more resistance than copper, so it gets hotter.
In a fan or a charger, the warmth is a side effect. It comes along but is not wanted. Too much of it can melt the plastic in a plug.
| Thing | Heat is |
|---|---|
| Room heater | The job |
| Electric iron | The job |
| Electric kettle | The job |
| Ceiling fan | A side effect |
| Phone charger | A side effect |