A stethoscope is used by healthcare professionals for auscultation, which is the process of listening to internal body sounds, primarily from the heart, lungs, and abdomen. It helps to assess heart rate and rhythm, detect abnormal lung sounds like wheezing or crackling, identify bowel sounds indicating digestion or obstructions, and is crucial for measuring blood pressure. The two sides of the chest piece—the diaphragm and the bell—are used to detect different frequency sounds, aiding in the diagnosis of various conditions.