Thermo Riddle / Puzzle

Seems like a question to weed out those that can't plan.

I wouldn't hire anybody that bought hot coffee 15 minutes before a meeting in which they were not allowed to drink.

This is an old 'standard'... John has it right.
I take it without milk 'cos it's better for my cholesterol level.
But I've found that taking it without cream is even better.

It does work in practice...if I need to rush out in the morning, I'll leave my cup of tea 'sans lait' until the last minute, it does get drinkable quicker.
Del (Hmmm dunno why I came over all Frenchified for a minute there?)

I take mine with soy milk, except when I'm on vacation - then it's nothing but heavy cream, baby!

But I've found that taking it without cream is even better.

Black w/ sugar for the win! Problem solved

Agreed - also means it doesn't go yucky when it cools down a bit, so it doesn't matter so much if an unexpected meeting pops up.

You could keep little cubes of cream in the freezer - it would save time + mess. I'm sure it would work......

I take mine without, but I'd be interested to know if anyone's tried this. Separation problems could probably be overcome. I'd be more hopeful of a good result with milk, but one never knows until it's tried.

Put the cream in a second cup, allow it to sit on your desk next to the coffee (ideally on top of the coffee), and then add the warm cream to the coffee after the meeting.

What is needed is one of those amazing KrisDel^TM gadgets that plugs into an USB port and sits under the cup to keep the coffee warm.

Another way to persieve this. If you look at the creamer and the cofee as 2 seperate entities then you can think of it as having hot coffe and cold creamer in room temperature for 15 min. The cofee gets colder the creamer gets hotter at least while both are approaching ambient temperature. The other option is to leave the creamer in the refrigerator for those 15 minutes. The coffe gets colder, but the creamer stays just as cold.

Add it to the coffee before -

Let us go to the extreme case - The coffee +cream eraches room temmperature

Now as per the Newton's law of cooling - it remains there

If you mix after - The cofee has already cooled down - less hot coffee+ same amount of cold cream = less than ambient result.

This will work for other values too - just I think the extremes.

Say the temperature is above in the ambient - then it will slowly drop towards ambient.

But not mixed - faster cooling rate +cold = less temperature

And same thing if the mix is below ambient- then it will heat up towards ambient.

Hence - mix before and have a cool coffee

Mix afterwards and have a cold coffee

Or, man-up, mix and drink (add water to cool further if needed), pop a breath mint, go to the meeting, have another cup after the meeting. Done!!

Hi Princess,

I would guess that the curves 2 & 4 should be the same. I suspect that this study was carried out with many cups of coffee an the cream added at differing intervals, the resultant being curve 4. Since adding cream needs stirring for homogenization one might wonder how much effect the stirrer (spoon?) would have to reduce the temperature? This may be the small difference between the curves.

regards

Chas

" ... how much effect the stirrer (spoon?) would have to reduce the temperature? ... "

And how about the Joule heating if you stir really fast and long ? Maybe with a thermally insulated spoon - or one with low thermal conductivity or low thermal capacity (low mass and/or low specific heat)?

Stir it with a very big hot spoon when you get back.

Hmmm . . . I had a grad student come to me once to ask if I could make a device so that he could measure how much energy was put into a stirred beaker water due to Joule heating. I made a very sensitive torque measuring apparatus, gave it to him and told him to go away and never come back.

Sorry. I didn't explain all that. They created a model of Newtonian cooling and determined the coefficients experimentally. Data was taken at 0, 2, and 28 minutes. The curves show what would happen if you had a 1 minute meeting, a 2 minute meeting, a 3 minute meeting, etc.

The stirring creates very little change in temperature. Joule had to stir like a madman for some time to measure any change.

But, yes, mix right away in order to get the hottest temperature any time later.

excessive curve fitting?

Why can't you just reheat the coffee after the meeting and then add the cream? After the meeting the coffee isn't going to be fresh anyhow, so why compromise the integrity and freshness of the cream by adding it before the meeting?

I don't know any company that is sadistic enough not to have a microwave. So I would reheat the coffee in the microwave and then add the fresh cream.

Well if we are going to tackle the design parameters...

Buy coffee, shove handfull of ice in

chug coffee on way to meeting

buy 'nuther coffee after

^{add cream and sugar and glop and slop if you must}

This is dependant on the temp of the cream and how much you like in your coffee.

I do know that two cups of coffee both at the same temp one with cream one without the one without will cool faster. Heat radiating out will pass thru the clear liquid. The milk solids will deflect it around.

You all do realize this is terribly unrealistic. Who the heck ever went to a meeting without carrying a giant coffee. God, without it, I'd snore over top of the Powerpoint talker.

Don't engineers run on coffee and pastries?

I would suggest using an insulated cup for the coffee and a metal vessel for the gream.

I like it Hot or cold, but not body temperature cause it makes me choke.

Put the cold cream in the hot coffee, buy another coffee and don't put cream in later and drink the one that you think is warmer.

(Our Starbucks was free so I would just give it to someone or dump it and get more later.)

Who did the research?

I think the ultimate question is how long is the meeting?

If it's anything like here, the coffee (subject to potential to localised nuclear detonation) would have no chance of being hot, warm or even cool post meeting. Cream or no cream it would be stone motherless cold after 4 useless hours of tedium.

Of course you could just HTFU and drink it straight away

That can't be an engineering meeting.

An engineering meeting is defined when the coffee and donuts arrive.

So it is a fifteen minute meeting--- not engineering---skip the meeting, a hot coffee will be more beneficial.

Engineering - Hell no, that's sales team for you. 0700 start NO donuts/danish, BYO/make your own coffee.

Why am I here again

Tell them to take Chinese tea. Either cool or hot, what different does it make.

Wonder why a lot of people like to take coffee. It just remind me, during my training in other country.

Early in the morning, we went to the office. After briefing, we had a cup of coffee, in this case is free.

Then we went to the plant for about 20 minute and back to the office and had a cup of coffee. During the discussion on the matter, another cup of coffee.

And this goes on until we finish works in the evening and wonder how many cuppa I have taken during the days.

Hot Coffee, Cold cream, some liquere, crushed ice cubes, mix, put in cold fridge, drink after meeting.

I'd be surprised if there were any noticeable difference in practice, but in theory should add the cream immediately. That cools the coffee so the rate of subsequent heat loss is lower.

Still the same if the cream is left out of the fridge to warm somewhat. The difference in rate of heat loss before and after adding cream is greater than the heat gain of the cream.

Cheers.........Codey

My friend had a calorimeter experiment in chem lab and it called for using a styrofoam cup and lid for the calorimeter. Their results were not too good. I told her to put the calorimeter cup inside 2 more styro cups for better insulation. Worked a lot better. There's always styro cups around an office, and I'd get a couple and set the coffee cup inside them like in a stack. I'd also put the cream in one and set it on top of the one with coffee in it.

Wow. This one has certainly generated some interest.

Just a side note that I have found the single most significant factor in having a warm cup of coffee minutes after you pour is what the temperature of your mug is before you pour in the coffee - nothing cools off hot coffee better than pouring it into a room temp coffee mug - ceramics just soak that heat right up.

For this reason, I preheat my coffee mugs with hot tap water first. Nothing worse than luke warm coffee.

New puzzle. Your coffee is too hot to drink, and you must have that java to stay awake for that morning briefing. No ice or ceramic cups available. How do you get it to potable temperature faster?

(Try half a dozen metal spoons.)

get a straw and blow bubbles into it.

Pour it into a saucer

pour it into a metal cup.

We are like minded. Check the bottom of post 33. (Hot spoon.)

I was guest.

We are like minded. Check the bottom of post 33. (Hot spoon.)

Since we're talking coffee and biscuits, some of you guys, most of whom I expect have quite a few years under your belts, might be interested in my latest development. It is powder form soluble Viagra. just stir it into the coffee, It's great stuff, does nothing for your sexual prowess but it stops your biscuits going soft when you dunk them!

regards (franchise enquiries welcome)

Chas

Good Grief, just use the powdered creamer that is all we have here anyway. I always wondered why and now I know. It is to prevent having 20 engineers standing around debating just this very question...

I'd go ahead and take the coffee with me. The only meetings I've been to that lasted only 15 minutes were me alone with a manager or two, and I got fired. If you're getting fired, one more violation of the rules won't matter, as long as it's not also a felony or something like that. If you're not getting fired, well, I've heard a saying, "You can get forgiveness easier than you can get permission."

I usually drink coffee from an insulated travel-type mug that keeps it hot way longer than 15 minutes. I take it black, but not like this, at home, but away from the house, I'll stop at a c-store and doctor it up with other things.

As far as I'm concerned, you win!

Yup, you win!