Date(s) - 22/03/2016
3:30 pm - 4:30 pm
Title: CAP Lecture – The Fire Within the Ear
Speaker: Dr. Christopher Bergevin
Institute: York University
Our ears are simply just soft, squishy microphones, right? Nope. For example, consider that down near the threshold of hearing, your eardrum moves approximately one picometer (for reference, the diameter of a hydrogen atom is 100 pm)! So even despite the presence of noise, somehow ears have evolved to become extraordinarily sensitive. How? This will likely come as yet another surprise: a healthy ear not only detects sound, but also emits it as well! These very faint sounds, known as otoacoustic emissions (OAEs), can be detected in the ear canal using a sensitive microphone. OAEs are generally thought to be a by-product of an underlying amplification mechanism at work, a “fire within the ear”. Not only do they provide a valuable probe into the biophysics of the cochlea, but also have important clinical uses as well (e.g., measuring for OAEs is how you give a newborn baby a hearing test). This talk will explore OAEs from a variety of different types of ears (e.g., lizards, tigers, owls, humans) so to help us understand the remarkable processes at work in the ear. Ultimately, the study of hearing is not only an instance where physics can meaningfully be applied to gain new insight into a “biology problem”, but the ear also presents a system with singular complexity that can guide us towards new physics.