In programming, constants are values that never change; they are comparable to unchangeable truths. On the other hand, variables are like containers that can be filled and emptied; they can hold a variety of values over time. Constants are therefore like immutable facts, whereas variables are like storage spaces for mutable data.
Here is an example from one of my favorite shows:
Ben Tennysonis the hero of the show, and he holds the powerful Omnitrix watch.