What are the differences between the bell and diaphragm parts of a stethoscope?

The bell and diaphragm are two parts of a stethoscope that serve different purposes. The bell is used to detect low-frequency sounds, such as heart murmurs, while the diaphragm is used to detect high-frequency sounds, such as normal heart sounds. The bell is typically larger and has a wider surface area, while the diaphragm is smaller and more sensitive to subtle sounds.