Final answer:
To test and dry out brakes after driving through water, a driver should apply the brake pedal gently at a low speed to help evaporate moisture and restore normal braking function.
Step-by-step explanation:
After driving through water, a driver should test and dry out their brakes after driving by gently applying the brake pedal while driving at a low speed. This allows the friction to generate heat, which helps to evaporate any moisture on the conventional disc or drum brakes. If the brakes are wet, the stopping distance will increase, and the brakes may respond unpredictably. Therefore, lightly applying the brakes intermittently after exiting a wet surface can help ensure that the conventional disc or drum brakes are dry and functioning properly. This is similar to a controlled experiment where the effects of water and oil on a sliding object are observed to understand how they affect friction and the object's stopping distance.