# Mug and Spoon Sounds

**URL:** <https://boards.straightdope.com/t/mug-and-spoon-sounds/464523>\
**Category:** Factual Questions\
**Created:** [September 21, 2008, 10:24am UTC](https://boards.straightdope.com/t/mug-and-spoon-sounds/464523 "2008-09-21T10:24:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![BrynSublime](https://avatars.discourse-cdn.com/v4/letter/b/7cd45c/32.png) [@BrynSublime](https://boards.straightdope.com/u/BrynSublime)\
**Post date:** [September 21, 2008, 10:24am UTC](https://boards.straightdope.com/t/mug-and-spoon-sounds/464523/1 "2008-09-21T10:24:29Z")

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When I stir hot coffee or tea, the spoon makes a _tink tink_ sound against the sides of the mug. However, when I make hot chocolate or broth the spoon makes more of a _thunk thunk_ sound on the mug.

**Why the difference in sounds?**

I thought at first it might be because the broth or chocolate is “thicker” than coffee or tea, but I’ve put enough cream in my husband’s coffee to make it far thicker than a light broth and still the sounds stay the same. What gives?

This has been bugging me for years and I’ve never found anyone that can answer. Thanks for your help!

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [September 21, 2008, 4:10pm UTC](https://boards.straightdope.com/t/mug-and-spoon-sounds/464523/2 "2008-09-21T16:10:50Z")

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The sound is related to how the sound propagates which is mainly determined by the viscosity of the fluid. Oil & milk solids (ie cream) mixed in solution with water does not have nearly as many particles in dispersion as cocoa or the colloids in dispersion of a broth. Even a glass of whole milk is going to sound more “tinky” than cocoa or broth. Put in chocolate milk powder and see how the sound changes.

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**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\
**Post date:** [September 21, 2008, 7:07pm UTC](https://boards.straightdope.com/t/mug-and-spoon-sounds/464523/3 "2008-09-21T19:07:55Z")

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This is a pretty well documented phenomena known in fact as [“the hot chocolate effect”](http://en.wikipedia.org/wiki/Hot_chocolate_effect)

It is related to the speed of sound in the liquid, not viscosity.