In this section, we explore how we hear sound through our ears, focusing on the unique structure of the ear that facilitates hearing. The outer ear is shaped like a funnel, which directs sound waves toward the eardrum, a thin stretched membrane that vibrates in response to these waves. This section features an interactive activity involving a tin can model of the eardrum, where students observe how sound vibrations cause the membrane to oscillate and make cereal grains jump. This highlights the eardrum's function as a key player in transmitting sound vibrations to the inner ear and then to the brain. Additionally, students learn about frequency measured in hertz (Hz) and how different sound properties, such as amplitude and pitch, affect our perception of sounds. The importance of sound clarity and frequency ranges that humans can detect, as well as how these properties relate to loudness and pitch of sounds, are emphasized throughout.