Thursday, April 28, 2011

Thurs-Demo: The one with hot cocoa

My department chair had been noticing that the noise her mug made when stirring hot cocoa changed as the mug heated up. So we shot some video and I present the following for today's demo:

Sound Changes in a Ceramic Mug from Matt Kuchta on Vimeo.

It's fitting, given that we had snow falling from the sky this morning.


  1. What's your hypothesis? Where's your need a cocoa-less control group?

  2. I noticed the same thing many years ago with my coffee mugs. I've guessed it was a result of heating changing the speed of sound, thus the resonant frequency, in the ceramic. But I don't know enough physics to feel very confident in that guess. Does it sound plausible to you?

  3. Lockwood - we were thinking that it's related to the speed of sound/frequency through the ceramic as it warms up. The first run with cold tapwater suggests it's not just because there's water in the mug, so it's likely to be related to the temp of the mug itself.