The adjective continuous describes something that occurs over space or time without interruption. Some computer fans make a continuous noise — a constant buzz — that can drive you to distraction.
Continuous things don’t stop, not even for a coffee break. A continuous sheet of ice has no cracks, a continuous noise never pauses, and a continuous line of railroad is the kind you want if you’re on a train. Continual, on the other hand, is used to describe things that start and stop occasionally. Use continuous for anything that goes on and on.