How Can I Calculate the Weight and Compression of a Submerged Coffee Can?

[2112]

Math isn't a strong point of mine, and hope someone could give me a valid response to this.
I'm still working on underwater physics, and have two questions.
First, if I had a 34 oz coffee can that I want to submerge below water to a depth of 8 feet, how many pounds would it take to get the can down that far, the can is opened at the bottom trapping the air in while being submerged, part two would be at the depth of 8 foot, how can I determine the amount that the air is compressed within the can.
I would figure it out myself, but getting underwater in a pool in Ohio at the present time would be just abit to cold.

 

[berkeman]

You don't need a pool, you just need to use some math. No excuses. Show us your work, and we'd be happy to help you.

1st cut -- how much does 34 oz of water weigh? 2nd cut, how much does 34 oz of air compress at that depth? 3rd cut -- solve the problem.