My parents keep bugging me to put in gas when there is about 1/8 tank left. They say that there are sediments that can block your fuel filter. This is sort of confusing, but the sediments (if there are any) would be heavier than the fuel, therefore settling on the bottom. And to my knowledge (or speculation), the car pumps the fuel from the bottom of the tank. Anything i should know about this subject?

 

You parents are right.

And, I believe that the fuel is not drawn from the bottom of the tank.

 

Fuel is drawn from the bottom of the tank through baffles. The baffles are there so you don't run out of gas on a hard right or left turn. The gas would all rush over to one side of the tank and your fuel pump would starve for fuel. The tank is made with baffles so some fuel stays at the pumps suction screen area.

Another reason for not letting your tank go so low is condensation. As the outside temp changes, condensation can form inside your gas tank it it's very low. Condensation = water in your fuel.

 

Not only is condensation an issue, but you can damage your fuel pump and fuel injectors if you run the tank dry.