explain why newspapers can keep icecream cold and fish and chips warm ?

[2010laura]

[ChuckFickens]

This has to be a wind up now!

[AlBags]

Same tick box again Laura. Thermal insulation.
You'd be better off watching a movie tonight with me, I think.

[2010laura]

nope sorry :(

[2010laura]

probs lol dont get why it would keep it hot and then another thing cold ? also why are cool boxes lined with expanded polysterene ?

[ChuckFickens]

Errrr, I think they would be better off doing their school homework rather than watching a movie with somebody from an internet forum as it goes!

[factor-fiction]

Only if you explain why you keep putting the full question in the title box and then leaving the question box blank!

[2010laura]

because i want to :)

[AlBags]

err ... yep, like you're Mr. Perfect ... from the Mr Muscle advert.

[AlBags]

They're all following the same principle Laura .. read the Wiki entry.
Thermal insulation will insulate hot or cold.

[Buenchico]

Thermal energy attempts to equalise itself across its environment. So heat moves from something hot (with a lot of thermal energy) to something cold (with little thermal energy).

However thermal energy is conducted only slowly though certain substances. Newspaper (and, just as importantly, the stationary air trapped between the layers of newspaper) acts as a partial thermal barrier because heat can only be conducted slowly across it.

When there's ice cream inside the newspaper, the equalisation of thermal energy means that heat is seeking to get inside the package, but is partially prevented form doing so by the thermal barrier of poorly conducting newspaper (+ air). So the ice cream remains cool.

When there's fish and chips inside the package, the equalisation of thermal energy means that heat is seeking to get out of the package but, again, the wrapping largely prevents it from doing so, the the fish & chips remain hot.

Chris

[2010laura]

ive done that 1 now :) just looking for why cool boxes are lined with expanded polystyrene ????

[2010laura]

thankyou :)

[Buenchico]

Expanded polystyrene is made from pre-expanded polystyrene beads. They trap bubbles of stationary air within the product. Stationary air is a poor conductor of heat, so expanded polystyrene forms a good thermal barrier.

[2010laura]

thankyou to everyone with relivent answers and not complaints about where i type my question :p x

[factor-fiction]

I thought your question sounded like a demand, so I replied in kind. I'm glad to see you have thanked everyone for their answers.
Qestions are easier to read if they are set out in the question box rather than wholly in the title box. That's what the Question Box is for
I also think all your questions were so similar you might as well have posted them all together. That way we could answer them all in one go. And it would have meant fewer questions from others would have been relegated off the page.
These are tips that you may choose to take on board or ignore.
Hope this helps.

[mollykins]

It works on the same principle as a thermos flask, you can keep coffee or tea hot or a cold, refreshing drink cool aswell.