The key to understanding this video comes when we realize that each time the tuning fork is held above the glass bottles you are actually hearing 2 sounds, not one. You are hearing the sound made by the tuning fork and the sound that reflects off the water and reemerges from the jar. When the reflected wave reemerges, it overlaps with the wave coming from the tuning fork. If the wave emerging from the jar overlaps constructively you will hear a loud sound. If the emerging wave overlaps destructively, you will hear no sound or a very low amplitude sound. For more on constructive and destructive interference, check out http://www.stmary.ws/highschool/physics/home/notes/waves/…
http://www.stmary.ws/highschool/physics/home/notes/defaul…
The video covers the anatomy and physiology of the ear and discusses the outer ear, the middle ear and the inner ear. Other topics include the eardrum (tympanic membrane), hammer (malleus), anvil (incus), stirrup (stapes), organ of corti, and the cochlea. Included in the video is a labeled diagram showing the parts of the human ear.
Try as you might, you can’t walk in a straight line without a visible guide point, like the Sun or a star. You might think you’re walking straight, but as NPR’s Robert Krulwich reports, a map of your route would reveal you are doomed to walk in circles.
Sound Waves And Their Sources (1933) – Educational film that covers the basics of acoustics. How sound propagates through a medium, pitch, timbre, loudness etc. Dated but accurate.
