Hmm...a question for those with better grey matter.

[madgaz]

Asked this on my Airsoft forum (just for the hell of it) and it has opened up a HUGE can of worms. The question also seems to have worked it's way onto Facebook too LOL.

Soo, if you had a bucket half full of water, lets say a 25 litre bucket, and added 12 fish of varying species and sizes, would the total weight of the bucket increase although the fish are floating?

This isn't a trick question, it's a daft question which turned serious LOL

[The Doctor]

The weight would stay the same because,adding anything to the bucket will not change the weight of the bucket and your question is aimed at the bucket and not the contents

[Driveby]

The weight of the bucket would stay the same but the weight of the bucket contents would increase, therefore increasing the overall weight of the combined bucket/contents as a single unit.

[ChrisW]

What they said ^^ lol

The fact that the fish are floating does not mean they are weightless tho Archimedes Principle! Their weight/mass varies via a swim bladder, hence they go up and down in the bucket, swimming a bit will help, lol. Over time there'd be a marginal decrease if you didn't feed them

Anyway, why are you keeping fish in a bucket? Very insensitive, I'm reporting you to the RSPCF

[madgaz]

OK, we're talking about the overall weight then and not the actual bucket.
Are you sure what you say is correct Chris?
And as for keeping fish in a bucket The question arose when me and r lass were cleaning the pond out, we couldn't empty the water out of the pond and leave the fish flapping in the bottom could we so we put them in a bucket half full of water

[ChrisW]

Because the fish are 'floating' their volume is equal to the weight of water they displace?

[flyingtele]

yes the above is indeed correct. The reason an object will float is if its total mass is less than the mass of an equivalent volume of whatever its floating in. The fish only float because the water is providing a supportive force that is greater than the gravitational force, ie the mass of the fish is less than the mass of the water they displaced, as previously discussed.

This does not exclude their mass from the total  though, as they are part of it. If you have half a bucket of water, and add 1 kg worth of rocks, the total weight goes up by one kg. So why should the same not apply simply because the fish are floating? If the bucket was full of a lighter fluid such as oil then the fish would probably sink (poor fish!).

If you have a bucket of mercury, then iron bolts will float. Wether stuff floats or sinks is just down to the mass of the object in comparison to the fluid its sitting in. Has no effect on total mass. That simple!

[calam]

Watched something similar on that Myth Busters program.
That was to do with birds in a lorry though. Was the lorry lighter when the birds were flying around?
In short the answer is no 

[ChrisW]

But when the birds are flying, they are self-supporting and not applying any force to the lorry's weight. When they land, their minimal weight is applied to the lorry's overall weight.

Imagine if you will, that you could levitate in your 4, would the suspension be supporting your weight?

[calam]

but what is causing the birds to fly
Its all about the downward force the birds create to make themselves fly.

They are not actually levitating in the air. Which i suppose is a different principal to the fish in a bucket but the result is the same.

Or is it   

[flyingtele]

Its a complete different principle lol. The birds in the air are flapping their wings, and the motion of that forces air down.  The resistance of the air provides a lifting force in the opposite direction. It's Newton's third law: For every action, there is an equal opposite reaction. The bird moves its wing, forcing air down. This creates lift, which is in the opposite direction. If the bird creates more lift than its body weight then it moves up The fish floating is just due to buoyancy, and that has been discussed above.

[ChrisW]

So if you're lying in a swimming pool and you fart, will you move forwards?

[Rob_A]

Are you on ASCUK or Arnies?

Or has there been other ones spring up in the last few years.

[madgaz]

Are you on ASCUK or Arnies?

Or has there been other ones spring up in the last few years.

I sometimes look at those but stick usually to my site forum (Cerberus Airsoft)