Hey, guys, let's do an example. The human ear can be modeled as a tube with one end open and one end closed the ear canal right outside the ear drum. If the length of the ear canal is roughly 2.5 centimeters, what would the fundamental frequency of standing waves in the ear be assuming the temperature inside the ear is out of a human body 37 degrees Celsius? Okay, if one end is open and one end is closed, this is a node anti node problem. If we're looking for the fundamental frequency, that's always a harmonic number of one, So remember any harmonic frequency for note. Anti Note is envy over for L, where in is odd, the fundamental frequency is just V over for L. Before we can solve this, we need to know the speed of sound in the ear canal. We're assuming that it's at body temperature, right? So it's the square root of one, plus the temperature in Celsius over to 73 times 331 m per second, and this equals meters per second. Okay, so the fundamental frequency is 53/4 times the depth of the ear canal, which is roughly 2.5 centimeters, or 30.20 to 5 m, which is 3500 and hurts. OK, just a straight up application off our equations for a node node standing waves. Alright, guys, that wraps up this problem. Thanks for watching.