fuel level drops when I brake? Help!

Hi, Yet another porblem with my 89 bird. This was ever since I bought the car, it really doesnt bother me, but I want to know. Why does my fuel level drop when I brake?? Its probably something simple, but hey I am still trying to familiraize with cars and every single aspect of what makes it work.

It drops because the fuel in the tank is surging to the front of the tank (away from the float) so the level drops until the fuel calms down and returns to level.

Thanks I just did not know.