Help with my home work

[CuteAngel]

Sorry to bother everyone but I am not very gud at physics. If u were makin a cup ov tea an da fone rang would you put da milk in b4 u answered da fone or when u got back to make sure da tea was hottest. thanks 4 reading everyone everyone xxx

[zig.zag]

you gotta be joking


lmfao

[tinkerbell23]

id put it in afterwards coz then u cud put less milk in if the tea had cooled??? lol!!!

if u put it in b4 then it would get cooler and cooler!!! hope that helps lol x

[Buenchico]

I can remember my science teacher asking that question 45 years ago!

The correct answer is to put the milk in straight away. It's all to do with cooling curves, as illustrated here:
http://www.davesbrain.ca/miscpix/coffee_w_milk .gif

Chris

[CuteAngel]

tanks tinker :D I will put that makes sense as will liquid will get smaller when its cold.

Thank You xxx

[CuteAngel]

chris how old were you then?

[Ethel]

cuteangel - he was 22.

[Buenchico]

I was 11 (or possibly 12) then.

[CuteAngel]

thats not fair then as I am much less than that. But they say scool is a gettin harder :)

[Buenchico]

Oi! I'm not that old, Ethel!!! ;-)

[CuteAngel]

oh ok chris lol he he thats less than me lol

[squarebear]

nah i wunt bovva puting ne milk in at awl coz i dunt av milk in mi tee lolol!!!!!111111

[CuteAngel]

hehe squarebear

[wildwood]

Your cooling curve makes no sense Chris. The sudden drop in temperature can not be the same in both instances when the milk is added.

[Buenchico]

Wildwood:
The diagram in that link might be a little 'idealised' but it's basically consistent with the one that I drew, from the results of an experiment, in my 1st Year ( = current 'Year 7') science lessons all those years ago. Further, it's consistent with the ones drawn by the youngsters I used to teach physics to (after they'd conducted an appropriate experiment) before I decided that teaching maths was a great deal easier than teaching physics! ;-)

Chris

[Ice.Maiden]

Have to just say Chris - you look well for your age!

[tamborine]

ma t cums wiv dry milk - in i jus ad 'ot wa'er :D

[vascop]

The main principal at use here is that the speed at which the liquid cools is faster the bigger the temperature difference between the liquid and the surroundings..
So a liquid at 80 degrees above room temperature STARTS cooling down twice as fast as one at 40 degrees above. Of course the speed of cooling gets less as the temperature drops, that's why the curves are less steep later.
The other assumption made in the drawing of those curves is that the same amount of milk has been added in each case.

[chakka35]

You don't need cooling curves or anything other than basic physics. As vascop says, the rate at which a body loses heat is proportional to the temperature difference between that body and its surroundings. Therefore the hot tea, left on its own, will lose more units of heat than will the milky tea in the same time. So put the milk in before answering the phone.

Don't want to be rude but is your strange use of the language an affectation or due to a difficulty in using it?

[heathfield]

If anyone's interested, the fats in the milk cool the tea at first, but then act as a form of insulation that reduces the speed of heat loss