Science Buddies: "Ask an Expert"

It must keep a soda pop can cool for a minimum of two hours. I can't spend more than $5 on materials, and can't use commercial insulation.

What would be the easiest (and quickest) way to build something?

I attend an "internet school" and this is my science assignment. It is due Sunday night, Nov. 11th. Since I don't have a science book, I'm kind of stuck.

Any help would be appreciated!!

Hi Daisy,

If you supply "how to build a thermos" to answers.com, you'll get back several suggestions. Please let us know if any of these work for you. Thanks.

Heat transfer by conduction is directly proportiional to the temperature difference, surface area, some insulation properties, and insulation thickness. Heat transfer by convection is a bit more complicated. You probably want to do some research into these properties.

What temperature is the soda can to start with?
What temperature is the ambient (room)?
How much temperature rise are you willing to accept in 2 hours?

Wadded up newspaper is a very low cost and suprisingly effective insulation. Commercial celulose blown insulation is is often made from recycled paper that is treated with a fire retardent.

Cardboard boxes make reasonable "coolers" to contain the insulation. Plastic bags are low cost air infiltration / vapor barriers.