Thermos flasks

[spudmuffa]

I am always puzzled when you put something hot into a thermos flask,it keeps it hot. When you put something cold into a thermos flask,it keeps it cold. But how does the thermos flask know???

[redhead23]

normally u speak to it hence it knows what u require

[chazza]

It doesn't, it just prevents any change in temperature

[BBWCHATT]

On the outside chance that you MIGHT be serious about this question:

http://en.wikipedia.org/wiki/Vacuum_flask

[Vasey]

ha ha ha ha ha ha

[Hammer Head]

When David Beckham played for Manchester United, the team had been given a day off from training so they decided to go into town and do some shopping. As they were walking past a certain shop, David suddenly stopped and seemed spellbound by something in the shop window. He asked Gary Neville what it was and Gary told him that it was a Thermos flask. "Wow", said David, "What does it do?"

Gary told David that if you put something hot into the flask it'll stay hot and if you put something cold into the flask it'll stay cold.

David rushes into the shop and buys one of the flasks.

Next day at the training ground, David turns up with his new Thermos flask.

"So what have you got in the flask?" asks Gary.

To which David replies, "three cups of tea and a choc-ice".