The average person would probably not really know the real difference between the two, but they do know that each cannot be connected to each other in the hopes that a DC motor will run from a house electrical outlet. They would soon find out that it was a wrong decision to make, and one they will never forget.
Thats the way it is with electricity. You don't see it, unless of course in what it powers, and for that reason, bare unconnected wires look harmless enough to give some unsuspecting do it yourself type of guy doesn't take any precaution when handling the wires. However, all it takes is one nice jolt, and learning lesson over.
I know. I was one of those who just never respected electricity. I still do stupid things in the way of not taking every precaution so as not to get zapped. I never turn off the circuit breaker to replace an outlet, or install a ceiling fan, or just about anything else that requires turning off the power for that circuit.
I do however know more than enough (through a lot of shock experience) to never assume I'm playing with dead wires. I always make sure the tools are well insulated. I figure as long as I don't make contact to the ground connection with a hot wire, its just a matter of normal procedure, but with "extreme caution."
I wouldn't recommend it this way to anyone, I couldn't live with myself if someone actually thought it would be safe to do. AC can kill you, and should be highly respected for what it can do. To get a better idea of how they differer from each other, (AC/DC) DC electricity from a battery, outputs a constant voltage over a period of time, and the output voltage will remain essentially constant. The same for any other source of DC electricity, the output voltage remains constant. This of course if the battery is always in the same amount of full charge.
AC source of electrical power on the other hand, changes constantly in amplitude, and regularly changes polarity, The changes are regular, and keeps repeating in over and over in identical cycles.
If you were to power up a DC bulb, it burns with a constant flow of electricity.
However, AC provides a on/off flow at sixty times a second. You just can't see it because it happens so fast that it looks as though the light is constant. However if you were to use a high speed recording of the light, and then use extreme slow motion, you would see that the filament goes from Orange to bright full light, and back again, over and over.