Have you ever been in a truly silent place? Even in the quietest countryside, there are still sounds, such as singing birds, and buzzing insects. Sound travels as invisible waves through the air. Your ears are specially designed to detect sound waves, turn them into nerve signals, and send these nerve signals to the brain, which analyses them and identifies the sound. The ears also receive signals that tell it how the body and body parts are positioned in relation to each other and the world around. This enables the ear to keep the body balanced. Otherwise, we would stumble and fall every time we tried to move. Disorientation after riding a roller-coaster occurs because the inner ears that control balance are temporarily confused and need time to readjust to the motionless ground.