Supposed we could remove all the waste from this conversation? What would that do to the discourse? I imagine it's small, but how small?

This is not really a math problem. It's a physics problem really. Goldfinger seems to have a real math problem. Please do share, goldfinger.

But yeah, let's assume that all the waste is floating. That means it displaces its own weight in water. A cubic meter of water weighs about a ton. The displaced water volume is therefore about 143x10^6 cubic meters. The oceans cover about 360×10^12 square meters and so the ocean level would rise by about 0.4x10-6 meters which is about 300 times thinner than a human hair.

If (part of) the waste did sink to the bottom then the ocean level rise will be even smaller. Sunk material displaces its own volume in water rather than its own weight. As it sunk its density must be larger than that of water. Thus the displaced volume must be smaller than the volume of an equal amount of water by weight (which is what it would have displaced if it was floating).

oscar I think you're wrong in your example.

floating objects don't displace their weight in water, they displace the volume of water that is proportionate to the mass below the surface of the water. A 4 lb. balloon filled with air displaces far less water than a 4 lb. block of ice.

The same with your sinking example. Any two equally-volumed objects with density greater than water will displace an equal volume (and therefore weight) of water when it sinks. So sinking objects displace more water than floating objects, not less.

Still, the main point stands, that volumewise, trash doesn't make a difference.

@YJ - read it again. That is pretty much what Oscar said.

No.

No, VB. What YJ said is entirely different from what I said. YJ is completely wrong though, as I will explain below.

Let's look at a cube with edge size A and mass M floating exactly upright in water. Let's furthermore denote the gravitational acceleration G, the density of water D, and the depth of the cube's bottom face below the water surface H.

Now for the cube to float the upward force Fb of the buoyancy must be exactly equal to the downward force Fg of the gravity. Because of the cube's upright orientation Fb is entirely due to the upward water pressure against the bottom face of the cube. This water pressure is G * D * H. To find Fb we simply have to multiply this with the area of the bottom, i.e Fb = G * D * H * A^2. This must be equal to the force of gravity which is Fg = G * M. Thus you find that H * A^2 = M/D. That is, the displaced volume of water H * A^2 is always equal to M/D no matter what A is. Or, in other words, no matter how large the cube, if it has mass M then the volume of water it displaces is M/D.

Now, for a balloon shape the calculation would be a bit more complicated but believe you me the result is the same: the balloon displaces its own weight in water no matter how large it is. As does a block of ice. And so no, YJ, a 4 lb. balloon filled with air displaces does not displace "far less" water than a 4 lb. block of ice. They both displace exactly 4 lb. of water.

As for sinking objects. Consider two objects both having mass M. Let D again be the density of water. Object 1 has a density X > D such that it sinks. It therefore displaces its own volume in water, which is M/X. Object 2 has a density Y < D such that it floats. It therefore displaces its own mass in water, which corresponds to a volume of water equal to M/D. Since X > D then M/X < M/D and thus, contrary to what YJ believes, a sinking object displaces less water than a floating object (of equal mass).

YJ, since you are apparently not even able to do 9th grade high school level physics, I suggest that you henceforth just shut the fuck up while the grownups talk.

@oscar

I understand what you're saying, now. You are saying that in the case of two objects of equal mass but unequal volume, so that one floats and one sinks, the floating object will displace more water. Granted, of course. An object cannot displace more than its own volume, ever, so a tiny, dense, ball won't displace as much as a floating ball of equal mass.

Now, what I was arguing was that in the case of two objects of equal volume but unequal mass, the sinking object would displace more water. That should also be obvious.

In other words, you were thinking in terms of equal mass, me in terms of equal volume. I misunderstood you, but I don't feel too bad, because you did the same to me.

I admit was wrong when I said floating objects don't displace their own weight in water. Forgive me, it's been over 5 years since I got my B.S. in physics - I haven't thought about this stuff in a long time. Chalk it up to the likelihood that I've probably forgotten more physics than you'll ever know. All that being said, you were such a condescending little prick about it that you can pretty much just go fuck yourself.

Just from me to you, as somebody who is about 2 months away from a PhD in a physics-related field, your attitude is really shitty. People will criticize your arguments. Those people will sometimes be wrong, or even more likely, just not fully understand. You need to learn to correct them gracefully.

@YJ

"Now, what I was arguing was that in the case of two objects of equal volume but unequal mass, the sinking object would displace more water. That should also be obvious."

Yes, that is obvious. In the context of a problem about a given mass of waste it makes no sense to consider two objects of equal volume though. And as you said this to refute my argument that this fixed mass of waste will displace more water if it floats then you were still quite blatantly wrong about the whole thing.

"In other words, you were thinking in terms of equal mass, me in terms of equal volume. I misunderstood you, but I don't feel too bad, because you did the same to me."

I call bullshit on this. You didn't misunderstand me. You misunderstood the physics of this problem. You're just now saying this to appear less stupid. That remains my take on it anyway.

"You need to learn to correct them gracefully."

Thanks for the advice. I already know how to do that though. I just chose not to do so in this case. I'm not your physics teacher. My aim was not to teach you anything. Just to troll you. I know, it's just too easy in your case.

"you were such a condescending little prick about it that you can pretty much just go fuck yourself ... your attitude is really shitty"

Great way to lead by example on the gracefulness. Hypocritical much?

"as somebody who is about 2 months away from a PhD in a physics-related field"

Wow. I guess a physics related PhD isn't worth as much as it used to.

^^always rewarding to know how somebody will respond before they do. Predictably played, sir.

how much popcorn will be displaced when i reach into the bag?

Depends how much of your hand you insert, about as much popcorn as your hand takes up (depends on method of insertion a bit). Though if we assume you're only putting the hand itself in, as long as there is more than a fists worth of empty space in the bag, none of it should spill over, which is what we care about.

ROFL.

@YJ

First you jumped the gun by saying that my calculation was incorrect based off your shockingly erroneous physics intuitions. Either you posted that without thinking or you're stupid without even knowing it. Either way it's childish.

Then, to hide your embarrassment over that idiotic post, you resorted both to backpedaling and to attacking my character. Again childish.

Finally, when that didn't really work either, you defaulted to acting as though the discussion played out just as you had planned. More childishness.

Nice, YJ, you argue like an 8th grader. I guess you probably are an 8th grader. Well, in that case I owe you a big apology for making fun of your inability to do 9th grade level high school physics.

Anyway, you should really learn to not be such a poor loser. You just end up making things worse for yourself. I'm sure you will learn this as you grow up. Good luck with that.

road rage

oscar is WINNING with TIGER BLOOD!

Ah, finally something we can agree on. ;-)

This thread hasnt taught me a damn thing about ocean trash but I have learned that YJ doesn't know shit about physics and Oscar is a douche canoe, so not a complete waste I suppose.

Mission accomplished.

@abge I already knew both of those things.

So, anyway YJ, what is this physics related subject that you are supposedly about to get a PhD for?

His PhD is in metaphysics.

Oh, are we playing nice now? No, I don't think so. I probably just made all that up.

His PhD is in aerodynamics and aeroplanes.

@abge you're such a dick. I love it.

His PhD is in Fluid Displacement.

"My aim was not to teach you anything. Just to troll you."

Le badass Internet troll trol u!! Xddddd

His PhD is in Melittology.

Careful, PE, or you'll be next to face that razor wit.

[queue menacing background music]

Edgy