eli5: Why does the pitch of the “mixing noise” decrease over time as a stir a hot drink?

Question

I’ve noticed this with lots of hot liquids. Once I start stirring, the clanking noise of whatever I’m stirring with just gets lower and lower in pitch, possibly as the beverage cools off. What is that? Thanks

In: Physics

Answer 1

For the same reason that the sink’s cold tap sounds different than the hot tap. The temperature of water affects its viscosity so that effects the sound as it pours as well as when it’s running through a sink valve.