The modern stethoscope is made up of a Y-shaped flexible plastic tube. An earpiece is attached to each end of the Y and a sound-detecting device at the other end. The sound-detecting device has a thin plastic sheet on one side and a bell shape with a hole in on the other. The diaphragm is used to listen to a patient's chest for high-pitched sounds. The bell end is used to detect lower-pitched sounds. The lung sounds have a higher frequency than heart sounds.