On Monday morning, before leaving for work, I took a ninth look at the ice bags.

Sensing that the weekend was over, the rice crispy ice had given up the fight. All that remained was a wet bag nestled in a soggy nest of once crispy treats.

I dug into the box and fished out two treats for my brown bag lunch. They were a little damp, but we have a killer microwave oven at work.

Monday Morning numbers:

Insulation Material	Remaining ice chunk size (approx. cubic cm)
Balloons	0
Aluminum foil	0
Diapers	0
goose down	0
rice crispies	0
cardboard	144
Styrofoam	2112

The Styrofoam still held ice, but the cardboard was on the brink of defeat. There was just a cocktail of ice remaining.

Monday was another hot day, but the cardboard continued to keep its ice solid.

A lunchtime checkup had the cardboard insulated box still in the running. The Styrofoam box was down to just 880 cubic centimeters of ice. This arctic struggle would end tonight.

It had just been a matter of time, and at 9:30 that evening, the styrofoam box came up liquid!

Styrofoam wins!

I celebrated by drenching myself with the victory water. Slow-thawed spring water, ahhh, it was delicious, and as cold as pure water can be in liquid form. 

The ice had lasted longest in the Styrofoam, 57 hours.

The other materials did not do as well, and after my face thawed, I made the graph below.

Styrofoam is the king, because it halts heat flow in three ways. It is white (limiting heat loss through radiation), made up of little cells (limiting convection), and contains a ton of trapped air (limiting conduction).

Styrofoam is also a great material for insulation because it can be manufactured into many form-fitting shapes, and because it doesn't attract bears, opossums, rats, ants, bees and wasps to your picnic like the Rice Crispy treats.

Thanks for reading Cockeyed.com Science Club: Testing Insulation.

-Rob Cockerham

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