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prairiesky
join:2008-12-08
canada

prairiesky to DataDoc

Member

to DataDoc

Re: How much will it float (55 gal plastic barrel)?

that's inherent in the calculation. If I have a drum, and put it into water, the force acting up on the drum is equal to the weight of the water. If the drum is filled with air, and hence lighter than water, it will float, if it's filled with concrete and heavier than water, the water is still pushing up with the same force, but it can't overcome the weight of it

here's one for you, a bowling ball has a certain weight, when placed in a canoe, it floats, but when placed into the water it sinks, why?

Locutus65
Why bother?
Premium Member
join:2001-05-24
Houston, TX

Locutus65 to Eric W

Premium Member

to Eric W
Um, because it's in a canoe

Coma
Thanks Steve
Premium Member
join:2001-12-30
NirvanaLand

1 edit

Coma to prairiesky

Premium Member

to prairiesky
said by prairiesky:

. . . here's one for you, a bowling ball has a certain weight, when placed in a canoe, it floats, but when placed into the water it sinks, why?

Displacement.
Waterbug
join:2008-03-30

1 edit

Waterbug to jfmezei

Member

to jfmezei
said by jfmezei:

If you vaccum the drum completely, the drum will weight less and thus provide greater bouyancy.
WRONG !! If the plastic drum is filled with a complete vacuum, atmospheric pressure will colapse the drum and it's only bouyancy will be the difference in the weight of the plastic and the weight of the water it displaces. Kinda like trying to float on an uninflated balloon or empty air mattress.

EDIT: Atmospheric pressure at sea level is 14.7 lb/sq.in or nearly 1 ton per sq. ft. (11sq.ft = 10.3 tons)

KrK
Heavy Artillery For The Little Guy
Premium Member
join:2000-01-17
Tulsa, OK
Netgear WNDR3700v2
Zoom 5341J

KrK to natedj

Premium Member

to natedj
Well it's about this displacement of water that leads to the buoyancy force. Anyway, the reasoning behind the styrofoam is that it will support and reinforce the plastic drum. Even if the drum gets dented, scuffed, a cut in it etc if full of styrofoam it will be essentially undamaged. (In it's role as the dock float)

brian
Premium Member
join:2002-05-02
Mission Viejo, CA

brian to Waterbug

Premium Member

to Waterbug
said by Waterbug:

said by jfmezei:

If you vaccum the drum completely, the drum will weight less and thus provide greater bouyancy.
WRONG !! If the plastic drum is filled with a complete vacuum, atmospheric pressure will colapse the drum and it's only bouyancy will be the difference in the weight of the plastic and the weight of the water it displaces. Kinda like trying to float on an uninflated balloon or empty air mattress.

EDIT: Atmospheric pressure at sea level is 14.7 lb/sq.in or nearly 1 ton per sq. ft. (11sq.ft = 10.3 tons)
I'm glad someone responded to this and explained it. I knew it was wrong, but couldn't explain why.

cowboyro
Premium Member
join:2000-10-11
CT

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cowboyro to Waterbug

Premium Member

to Waterbug
said by Waterbug:

WRONG !! If the plastic drum is filled with a complete vacuum, atmospheric pressure will colapse the drum
How can you *fill* a container with complete vacuum???
Anyway... this is what happens to a container that is being emptied:

»www.youtube.com/watch?v= ··· ci9vrvfw
DrD
join:2008-03-03
Harrisonville, MO

DrD

Member

We had a tornado go near some giant gasoline containers, and they imploded with the pressure difference.
Waterbug
join:2008-03-30

Waterbug to cowboyro

Member

to cowboyro
said by cowboyro:

How can you *fill* a container with complete vacuum???
From some of the posts and responses that I have seen in this and other forums, it happens all the time.