Pick A Hexites Brain.

[Stewart]

So we have some smart folks on this here forum, peeps from all walks of life, who know a thing or two. So, lets have a question and answer thread. Someone posts a question they want the answer to, anyone who knows chips in with an answer, in simple terms that even a spaz could understand. And it goes from there.

Capiche?

Sorted.

I'll start: The USS Nimitz, part of the US Navy fleet, weighs in excess of 100,000 tons.

So...

HOW THE ARSE DOES IT FLOAT?!

[staffsMike]

Ballast and boyency

drop a penny in a pond it falls to the bottom but stick your pocket change in an empty can of coke and it floats

As long as there is more boyency than weight it will float.

Ships also use ballast tanks (tank of water essentially) to keep it floating at the right height in the water for the load it is carrying and to keep it balanced.

[Funkstar]

I'll add to staffsMike's answer. Because of the size ofthat 100,000 tons, it's density is less than that of the water it would displace, so it floats

Or something close to that anyway.

[staffsMike]

I'll add to staffsMike's answer. Because of the size ofthat 100,000 tons, it's density is less than that of the water it would displace, so it floats

Or something close to that anyway.

Indeed, I meant to add something to that effect.

[Stewart]

Ok, this is one that we can just share our ideas on really, as noone is going to know it exactly.

And it is simply...

...


...

What the hell is Déjà vu all about then?

[Agent]

Short circuits in the brain, apparently.

[Funkstar]

it's a glitch in the matrix isn't it?

[Stewart]

Short circuits in the brain, apparently.

That 80s robot? He aint got nowt to do with it.

Johnny 5 is alive!

[Whiternoise]

ship will float when the weight of the water it displaces equals the weight of the ship

In other words if we know the density of the ship, and if it's less than water, we'll know if it'll float and how much it'll sink by.

Ok, a few figures to begin with:

Volume of the ship is about 50 * 300 * 50 = 750 000m3 (height, length, breadth averaged a bit)
Weight of the ship total is 100 000 tons
Call the volume of the ship in a more appropriate shape as 400 000m3
So it's got a density of say 0.25 tons per cubic metre

Density of water is 1 ton per cubic metre

Ok, put into context. The ship weighs a hell of a lot, it's also bloody massive.

BUT, when you put it into different terms, it has a density of about a quarter of water. The ship is say 50 metres high discounting the mast, so in theory it should sink about 12.5 metres into the water (from a quick look on wikipedia, 12.5 metres is it's structural limit, so i think my calculations are about accurate - especially with my roundabout figures ). Most of that volume is going to be made up of air, which has a density of about 1/800 that of steel, so it doesn't take much air to counteract the weight of the ship.

Hope that helped, if you need any more clarification then don't hesitate to ask!

Further reading: Fun Facts - Why Do Ships Float?

[pauldarkside]

So, lets have a question and answer thread. Someone posts a question they want the answer to, anyone who knows chips in with an answer, in simple terms that even a spaz could understand.

Don't the collective attempt to do that already?

[kasavien]

I've been looking into this recently because i get it quite often and it bugs me and freaks me out in equal measures. Wikipedia is a good start although don't read it if you want to keep thinking that deja vu allows you to see the future

Déjà vu - Wikipedia, the free encyclopedia

[staffsMike]

Don't the collective attempt to do that already?

We are the borg..

[pauldarkside]

We are the borg..

Yep and I'm 18580 of 32992 and I don't look good in lycra

[Whiternoise]

Here's one to boggle your brain.

Say you're going to click on the start menu button (assuming you're using windows ). You think "aha, i shall click on the button now" and your hand moves the mouse accordingly. But think of it another way, you already DECIDED to move your hand before the thought popped into your head. In this way, a lot of things you do are determined before you think about doing them..

Job interviews for instance, a common example. A study showed that students watching two 10 second clips of two teachers teaching (without audio) formed the same impressions as students who watched a 5 minute video or students that had been taught for a term by both teachers. Even scarier, students who saw the clip for less than 2 seconds formed the same opinions. This basically means that your interview is over before you've even shaken hands. All your chit chat about CV's and questions about what you can do for the company are merely reinforcing the decision made by your prospective boss as soon as you walk in the door.

In this way, you could see Deja Vu as simply your brain processing the information before you have time to think about it. Then you DO think about it and think hmm this seems familiar - i.e. your subconscious is working faster than your conscious. Whether this is all crock - i'm not a psychologist - it's all interesting stuff..

Bring on Time Travel already! We can get confused for hours about that!

[[GSV]Trig]

I really dont like deja vu and dont think its my brain short circuiting as I've had several minute long deja vu episodes..


I also find that deja vu and my alzheimer's dont get on well as I'm sure I've forgotten this conversation before..

[alsenior]

someone had to might as well be me

Plane on a treadmill...
...follow the link below:

http://pogue.blogs.nytimes.com/2006/12/11/the-airplane-treadmill-conundrum/

Does the plane take off? Of course it bloody does. But another forum I post on have been posting for pages and pages arguing both ways. In fact here's a 443 page (and counting) thread on a physics forum on the same subject that has been going over a year:

PhysOrgForum Science, Physics and Technology Discussion Forums -> Plane on conveyor... Will it ever take off?



Answers below please