Functional verification

Functional verification is like when you are trying out a toy you just bought to make sure it works the way it's supposed to. For example, if you buy a remote-controlled car, you want to get it out of the box and check that all the buttons work, the wheels spin, and it moves the way it's supposed to. You don't just want to open the box, look at it, and think, " Yep, that looks like a car; it must work." That's why you do functional verification - you have to actually check that it does what it's supposed to do.