Some refill, some do not

Sunlight comes again tomorrow. Coal does not. That is a big difference.

Renewable — a resource that refills in time. To refill is to come back again. Sunlight, wind and forests are renewable.

Non-renewable — a resource that does not refill in our lifetime. Coal, petroleum and metal ore are non-renewable. Petroleum is oil from under the ground. Ore is rock with metal in it.

Rule: A renewable resource refills in time. A non-renewable one does not refill in our lifetime.

A renewable resource can still be used up. That happens when people take faster than it refills. A pond has 100 fish. 10 new fish are born each season. People catch 20 each season. The pond loses 20 − 10 = 10 fish each season. 100 fish ÷ 10 fish a season = 10 seasons. After 10 seasons, no fish are left.

Try the lab to finish this lesson.