conservation of energy
nounUK /ˌkɒnsəˈveɪʃən əv ˈenədʒi/
US /ˌkɑːnsərˈveɪʃən əv ˈenərdʒi/
Energy cannot be made or destroyed; it only changes from one form to another.
The conservation of energy explains why a swinging pendulum keeps moving back and forth.
OTHER MEANINGS
2. The practice of using less energy to save resources and money.
Turning off lights when leaving a room is a simple act of conservation of energy.
3. The idea that the total energy in a closed system stays the same over time.
In a closed system, conservation of energy means the total amount never changes.
4. A fundamental rule in science stating that energy can change forms but never disappear.
The conservation of energy is a key rule taught in every physics class.