Coffee Question  

_CoffeeNoCream_ 54F
6527 posts
4/12/2005 8:17 am

Last Read:
3/5/2006 9:27 pm

Coffee Question

If you tap against a cup of coffee when you add milk powder, the pitch changes.

Why is that?

A: Additional air is brought into the coffee, thus changing the speed of sound in the cup of coffee.
B: The fat in the milk powder changes the frequency response of the coffee in the cup
C: The dissolution of the milk powder cools down the coffee, thus changing resonance frequency of the cup of coffee

Ok Coffee blog lovers.....gimme your answers and simply A/B or C is not enough....explain yourself.....use those brains !!!!
I will give you the answer later this week and feel free to google...

Liefs Coffee

lustmirror 64M
2897 posts
4/12/2005 11:03 am

The answer is A
the anticipatory response mechanism of having coffee so close at hand lowers the expecto-adreno response, just slightly, in deference to the realization that help is on the way. ergo...the tone drops, and the bad bad headache subsides.....

sound moves slower through air, than through liquid...
try aying THAT three times, under water.

lustmirror 64M
2897 posts
4/12/2005 11:05 am

by the way...if you tap the side of your coffee cup
you MAY be expected to make some sort of announcement
to the raised eyes all about the room

rm_indul_gent1 57M
89 posts
4/12/2005 11:46 am

Ok, I'll bite ...
I'll say (that the fat content of the milk powder alters the density of the coffee in turn producing a pitch variation. I'm not sure sufficient air is introduced nor do I think that temperature affects the pitch ... but I'm no scientist.
What does the correct answer win?

rm_indul_gent1 57M
89 posts
4/12/2005 11:48 am

my answer was B .. in case there was some doubt ...
apparently B inside () ... is code for one of those smiley things

papyrina 52F
21133 posts
4/12/2005 11:49 am

who on earth uses milk powder,urggggggg

I'm a

i'm here to stay

LimesMastsAvoid 71M
456 posts
4/12/2005 12:00 pm

Its not A, B or C....its called " Turbidity "....the effects that suspended particle size, shape, distribution, and the added spoon vibration, which, if you listen carefully, sounds like an elf pissing on a waffle...or in France, a crepe....

rm_indul_gent1 57M
89 posts
4/12/2005 1:58 pm

Damn, there are some clever people on this site. I think Papyrina's response is most appropriate.

ccninja 43M

4/13/2005 8:21 am

I think your wording may have given the answer away. My first guess was B, but I've decided it's probably really C through the process of elimination.

I don't think it's "A" because if the speed of sound changed, that should only change how fast the sound travels and not the pitch.

I don't think it's "B" because a change in the frequency response should not change the pitch either. It would make the sound more loud or more muffled, but it wouldn't change the actual pitch.

Assuming you've used the right terminology, it has to be "C" because only a change in the resonance frequency could change the pitch.

This is just my guess, so I hope I haven't ruined it for the others. I could very well be wrong. That happened to me one other time back in 1979.

redswallow777 49M
6811 posts
4/13/2005 9:32 am

I agree with indul gent1. My hat is off to all the clever folks who have responded. It is good to have you back and writing CoffeeNoCream.

redswallow777 49M
6811 posts
4/13/2005 9:35 am is interesting that your mood was horny when you wrote this blog entry....I would have expected inquisitive or playful....

_CoffeeNoCream_ 54F

4/13/2005 12:18 pm

what would you like to win @ indul_gent1 ?

_CoffeeNoCream_ 54F

4/13/2005 11:58 pm

@redswallow.....the horny mood.....that was just a test to see if people actually look at my mood....obviously you do...*grins*

redswallow777 49M
6811 posts
4/14/2005 2:11 pm

<----Whew, maybe there still is hope for this ol' guy....even if the nose doesn't work anymore....just need to get her to print it out each time....

_CoffeeNoCream_ 54F

4/16/2005 6:18 pm

mmmmmm not many who have the guts to try....

_CoffeeNoCream_ 54F

4/16/2005 6:19 pm

I will post the answer after this weekend

nightstogether 58M

4/16/2005 11:48 pm

I would say because the density of the fluid inside the cup has changed. When you stir coffee quickly and come against the base or side of the cup, the sound is also of a different pitch as when you do it slowly, or when the fluid is not moving.

private-intellectual (.de)

keithcancook 61M
17956 posts
4/17/2005 4:06 pm

I only drink black coffee. I enjoy its bitterness. (third attempt to get a comment to stick here)

rm_49erDee 68M

4/17/2005 7:18 pm

4plait, when in the name of God did you ever chance to hear an elf piss on a waffle? I used to work for a water company, so I had heard of turbidity, and that sounds quite plausible. But I have to admit I never heard it explained as you did. Thanks for teaching me something new today.

rm_Blinkey46 59M
4 posts
4/18/2005 4:53 pm

The pitch changes because the temp of the coffee has changed and changed the density of the cup . Try stirring a cup of coffee with a spoon and listen to the pitch change even if you do not add anything

rm_Neza1966 51M

4/19/2005 2:26 pm

Hey you killed the result of my googling .... or dit AdultFriendFinder kill that?

rattleandhum69 48M
2 posts
4/26/2005 2:15 pm


the warm juices of good coffee in a well painted cup will change, of course together with a well sculptured spoon at the right timing of entry will cause an explosion of vibrations and aroma that spins the mind.

dear bittersweetcoffee lady,
you tell me your answer then. and come to think of it, 'coffee' should best be consumed in the morning!

thank you for rattling my brain and getting me to hum every time i consume coffee.

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