To those who remember their physics better than I do

[karohemd]

A glass bottle of milk is placed on a doorstep and left there for 6 hours. Will it have frozen by the end of that time if it was around +4°C when placed there (I don't think it'll be much warmer on the back of an open lorry) and the outside temperature is -8°C? (it's already -6 according to the thermometer at the garden fence and bound to drop a few degrees)

Comments

[robinbloke.livejournal.com]

Milk freezes around -0.5 degrees C (although this depends on the fat content of the milk) and I've found takes around a day or so to completely freeze in my freezer at -18 degrees, so it'll certainly be at least partially frozen

[gnimmel.livejournal.com]

An empirical data point: while we were away at the start of the cold snap, the milkperson ignored our note and made a delivery. So when we got back there were two milk deliveries, one of which had been there for a couple of days ad one of which had been freshly delivered that morning. The first delivery was frozen solid, the second was still liquid.

[karohemd.livejournal.com]

Interesting, thanks! I'm just surprised it was still there. Mine gets nicked on a regular basis. :/
Stupid milk person. I always call to cancel for holidays just to make sure.

[gnimmel.livejournal.com]

Ours gets nicked too occasionally, but since we're down the end of a cul-de-sac which was like a skating rink at that point, I think the thieves were feeling insufficiently determined!

[missdiane.livejournal.com]

Wow...they still deliver milk?

[karohemd.livejournal.com]

Yep, and really good it is, too (at least the organic full fat milk).
The main reason why I use the service is because I want to cut down unnecessary rubbish. I also get orange juice from them.

[susanofstohelit.livejournal.com]

today I declined to do a science experiment seeing if eggs would freeze in my car between lunch and coming home. but the high was 8f/-13c.

[undyingking.livejournal.com]

Physics would only help with the calculation if the milk bottle was black, spherical, pointlike and in a vacuum. Any sort of real-world situation, you need engineering.

(Speaking as a former physicist ;-)

[karohemd.livejournal.com]

Heh. It didn't actually freeze and neither did the orange juice.