Cubic feet and gallons - Math Central

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Question from Leonard, a parent:

Every conversion I find to convert a cubic foot to a gallon is in liquid.
Question, how would 1 cubic foot convert to gallons in dry measurement?
Example say you have 1 Gallon of packing peanuts how many cubic feet would that be?
I can do this and have done it for the heck of it, I took a box 12x12x12 inches, which is a cubic foot,
filled it with packing peanuts the tried to fill a 1 Gallon container, that amount almost fills a 1 gallon
bucket twice.
I even ask a math teacher and was told that 1 cubic foot equaled 7.481 gallons,
then I said that is liquid, teacher answered yes, then i ask what about dry and got
a response of I do not know.

Hi Leonard,

The equivalence of 1 cubic foot to 7.481 gallons is not dependent on the material. It is the same for liquids and dry materials.

There may be a couple of problems with your experiment. Are you sure your "one gallon bucket" actually holds one gallon which is 128 US fluid ounces? If you still have your one cubic foot box then try it with sand or some other dry material that is fine grained. Part of the problem may be that you can't really fill the box or bucket with packing peanuts. There is a lot of air space between them.

Harley

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