How can dynamic and static pressure be explained?
You are very close. Your explanation of static pressure is correct, but not your dynamic pressure. Ram air pressure is what the pitot tube measures, in other words the total pressure experienced. It is your airspeed gauge which measures dynamic pressure by mechanically (in the case of a traditional pitot-static system) subtracting static pressure from ram air pressure. 

If I was explaining this to a layman I would say that ram air pressure is equivalent to sticking your hand out the window of a moving car, while static pressure is the pressure inside the car. That's a bit of an over-simplification as the pressure inside the car will be lower than outside due to the movement through the air, but it gets the point across.