What is the best thermal/heat insulator?

Question

I have to construct an insulating device to minimize heat transfer in order to accommodate an ice cube for a minimum of 1 hour. The insulating device has to be of 3 layers and its materials should be easily available. Can anyone please tell me what should I use for the 3 layers?

Maximum outer dimension = 15cm x 15cm x 15cm

Minimum interior dimensions to accommodate an ice cube of dimensions 3cm x 3cm x 5cm

Device/Container opens and closes

Thanks for helping! :)

Answer 1

Glass, plastic, and rubber should work fine.

Answer 2

Sealed air is probably your best option. Things like bubble wrap make good sealed air insulators.

Answer 3

1) Pre-chill the inside of your compartment (if it is allowed).  This will serve you very well in the "competition".

2) Glass is an excellent conductor of heat.  Do not use it (unless you have a vacuum available).

3) Styrofoam is a good choice.

4) "Pink" fiberglass roofing insulation is also effective.

You could layer styrofoam/fiberglass/styrofoam.  Look at your heat transfer equation.  Note how area and thickness are represented.  This will help you determine the "best" tradeoffs for size.  The seal will be the "worst" part of this cooler.  A tongue and groove would be excellent.  Again, put your insulation material in a freezer before starting the clock.

Good luck.

-Fred