School Ice Box Project

[Student_777]

Ok theres a project in my science class at school called the Ice Box project. The goal is to create an icebox (without just buying a cooler) that holds ice in it for 24 hours. I was thinking about using tinfoil and stuff but im lost.

 

Any ideas?

[John Cuthber]

I'd start by thinking about how heat is transfered and what I could do to stop it.

[Student_777]

I never thoguht of it that way. i was thinking, what if i make the ice box, wrap in in multiple layers of tinfoil, and freeze more than 48 hours, then brought it in to school to leave over night...

 

Maybe like insolent? My dad has a can of spray insolent, you spray and it hardens up super hard and expands.. hrmm..

 

Anyone out there to help?

[encipher]

Dewar/Vacuum flasks are commonly used to store cryogens (such as liquid Nitrogen or Oxygen).

 

The following was taken from the Wikipedia article on Dewar flasks:

 

A vacuum does not conduct heat by conduction or convection' date=' but only by radiation. Radiative heat loss can be minimized by applying a reflective coating to surfaces: Dewar used silver.

 

The contents of the flask reach thermal equilibrium with the inner wall; the wall is thin, with low thermal capacity, so does not exchange much heat with the contents, affecting their temperature little. At the temperatures for which vacuum flasks are used (usually below the boiling point of water), and with the use of reflective coatings, there is little infrared (radiative) transfer.

 

The flask must in practice have an opening for contents to be added and removed; as a vacuum cannot be maintained at the opening, a stopper made of thermally insulating material must be used, originally cork, later plastics. Most heat loss takes place through the stopper.

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[Student_777]

Sorry im only in 8th grade and have no idea what that means. its just plain old ice i have to keep frozen for 24 hrs. How do i use a vacuum on it?

[John Cuthber]

Heat gets transfered by convection, conduction and radiation. The first 2 need something to carry the heat so if you can trap a layer of vacuum (OK, I know that's an odd way of putting it) around the thing you want to keep cool you wil prevent heat reacching it by convection and conduction- that only leaves radiation to carry heat to the ice. If you wrap a mirror round it the radiant heat will be reflected away. You might want to look at the wiki article on vacuum flasks.

 

OTOH, I don't think you are going to build a vacuum flask as a school project so I would concentrate on good insulation. I guess that insolent stuff is some sort of aerosol can full of foam. If so it's probably very good for this sort of thing. A couple of boxes, one inside the other and with the gap between them filled with foam (styrofoam works too) would be a very good start. (You need a "foam" lid too- obviously).

[Student_777]

I guess that insolent stuff is some sort of aerosol can full of foam. If so it's probably very good for this sort of thing. A couple of boxes, one inside the other and with the gap between them filled with foam (styrofoam works too) would be a very good start. (You need a "foam" lid too- obviously).

 

Sweet thanks. And yes it is a foam filled can. And how woukld be a good way to reflect light off my ice box? would the shiny side of tin foil work?

 

Anyways, I'll look up those three words and learn more about them.

 

Thnx!

[John Cuthber]

"would the shiny side of tin foil work? "

Yes.

[Student_777]

my dad has this thick metallicy stuff i, you can bend it east and he said it would protect radiant heat easily, it starts with a M. My dads a senior captain firefighter so he knows a lot about hazmat and science things.

[Klaynos]

my dad has this thick metallicy stuff i, you can bend it east and he said it would protect radiant heat easily, it starts with a M. My dads a senior captain firefighter so he knows a lot about hazmat and science things.

 

Metal will stop radiant heat, but what about conduction? Why are sauspans made from metal?

[Darkblade48]

my dad has this thick metallicy stuff i, you can bend it east and he said it would protect radiant heat easily, it starts with a M. My dads a senior captain firefighter so he knows a lot about hazmat and science things.

You're probably referring to Mylar in this case.