Check out this cool video and learn how to create the Allassonic effect with a coffee cup, instant coffee and boiling water. When the bottom of a ceramic cup filled with boiling water and a heap of instant coffee is tapped at regular intervals the pitch of the sound heard slowly increases over time.
The effect takes its name from "allasso", the Greek root for to change, and "sonus", the Latin word for sound.
In the past the effect has been referred to as the "Hot Chocolate Effect" but the phenomenon is found to occur in many instances beyond the humble cup of hot cocoa. It can even be heard when the base of a pint of beer is tapped after having sprinkled some table salt into it. This is a great science experiment to try with the kids. Watch this tutorial and create an allassonic effect at home.