Which everyday process is used when a doctor listens to heartbeats through a stethoscope?

Which everyday device uses the principle of capillary action to function?

Which famous experiment proved that the Earth orbits the Sun rather than the Sun orbiting the Earth?

Which layer at the back of the eye contains photoreceptor cells called rods and cones that detect light?

Which law explains the equal and opposite reaction observed when a rocket launches?

Which gas is responsible for the characteristic smell often associated with rain after a dry spell?