New Nebula Types

posted on April 10th, 2010, 10:35 pm

Nope, there are a fair amount of exceptions - like silicon for example

posted on April 11th, 2010, 12:26 am

Any non-nutoinum fluid would work.

Like ketchup 

posted on April 11th, 2010, 2:08 am

o ok i must have slept thru that part of the class but still as a general rule solids are more dense than liquid. (ok i might have been a sleep during the class too but thats how i remember it)

posted on April 11th, 2010, 4:38 am

Ok that's confusing to me. Density doesn't mean more solid then? Cause I'd say 3ft x 3ft block of ice is denser than a 3ft x 3ft pool of liquid water. But if your saying that ice is just rearranged molecules of water forming a solid but it's not more dense than in liquid form. Oi I confuse myself....

posted on April 11th, 2010, 5:52 am

Density is matter's mass divided by its volume.  So something is more dense if it has more mass packed into the same volume of space.  The table your computer sits on is very dense like most solids.  As Dom said, ice has a crystal lattice structure.  Another way to think of it is like a sky scraper being built.  The lattice structure is like all the I-beams you see, and there is tons of space in between those beams.  Water would fill the gaps, but ice ends up taking up more space, with many gaps.  So it has less mass per volume of space compared to water.

It's just like if you put a bottle or can of coke in the freezer.  It breaks, because it's mostly water and there's no where it to expand to.  And then you get to clean up the freezer.  I learned that the hard way when I was younger.

posted on April 11th, 2010, 5:56 am

hmm More solid?? its either solid or its a liquid there is no in between. Denisty is a measure of how closely arranged the atoms are. A simple way to express it is by its mathematical definitional, density is mass (weight) divided volume. Lead for instance is a very dense metal while aluminum is very um un-dense (cant think of the opposite of it)

Cause I'd say 3ft x 3ft block of ice is denser than a 3ft x 3ft pool of liquid water.

This is where you are incorrect (mostly due to the reason i explained above) if you could measure the weight of the two you would find that the ice weighed less.

A simple example of this would be to take a water bottle that was completely full (with the cap on) and place it in your freezer. After a couple of days you would come back and find that either the cap would be broken or you would have a very deformed bottle. Why because as water freezes it expands to fill up more space.

One final thing to note is that if Ice was more dense that water it would sink to the bottom of your glass instead of floating on the top.

Edit :shuriken:ed by mal. Come on you even used my examples too

posted on April 11th, 2010, 2:44 pm

Just one thing to nitpick  : mass is not weight. Weight is not a constant (because acceleration due to gravity changes depending *where* you are) but the mass of an object is constant.

posted on April 11th, 2010, 5:58 pm

Thanks for clarifying that. You guys are a great collective of knowledge. Been like 12-14 years since I studied this stuff.

posted on April 11th, 2010, 8:01 pm

Hey Mal, Dircome, Dominus. I'm one moment afk and you're doing my job? 



Hmm, Somehow I feel I need to have the last word. Let's see if I can find something.

posted on April 11th, 2010, 8:29 pm

Ha!

I can nitpick on dominus too!

Explain plz? High pressure = high temperature = high density i thought?!

What Mimesot explained is simple ideal gas-law kinetics .

It's not only ideal gas kinetics, but also real gas kinetics

I'f i'm correct, temerature does not rise in an ideal gas, as you kompress it. There's no reason for pointy, fully elastic particles to become faster (which is Temperature averaged over the whole lot of particles) just because there's less space to move in. (Ideal gas law NkT=pV=const.) On a realistic gas, particles are interacting, every particle in it's neighbors interaction potential. A energetically negative (binding) potential. If molecules come closer in average - meaning th gas is kompressed - they are in average more in their neighbors potentials, their av. potential energy sinking. Due to conservation of energy their av. kinetic energy will rise accordingly, meaning it will get hotter there.

Nevertheless in princple ideal gas laws are sufficient to explain, why a gas reacts against compression. Pressure x Volume is constant. Reduce Volume and the pressure will rise, creatig force outwards.

posted on April 12th, 2010, 3:53 am

Ik dom i was just simplifying it a little bit

posted on April 12th, 2010, 5:28 am

I'f i'm correct, temerature does not rise in an ideal gas, as you kompress it

Ideal gas law NkT=pV=const.

So may i ask 1 question?

when p is increased...what will happen to T when N and k (as usual) are fixed?

posted on April 12th, 2010, 8:00 am

Huh?!  When did this thread turn into junior high school science? (with a  C average)

I can answer your question, Durr, using the same formula I developed in Chem 11, before being asked to leave that class.

Q:  when p is increased...what will happen to T when N and k (as usual) are fixed?

A:   M
Showing My Work:  M=Correct Answer.

There you have it. 

Now I'll throw out another NEBULA TYPE I thought up: Unexplainable Star Trek Thingy Nebula
On those damned shows they've countless times managed to cook up some oddball idea to centre an episode around.  This nebula (insert name) does something to a ship that flies into it, or maybe to the crew to make them go crazy.  Some stuff happens, until they manage to leave or escape the nebula, or reconfigure the deflector array to fire off some kind of bloody beam into it and neutralize the thing, or reverse the nebula's effect back onto itself (ie:  the nebula goes crazy)

posted on April 12th, 2010, 10:02 am

So may i ask 1 question?

when p is increased...what will happen to T when N and k (as usual) are fixed?

if pV=constant and pV=nkT => NkT=const. You don't change Nk, well, T won't change either. So when you change V, p changes inverse proportional, N,k,T don't change at all.

@Prof. J: 

Still,FO is harder SciFi than StarTrek itself. Things in FO seem to be intentional, sometimes even logical.

posted on April 12th, 2010, 10:45 am

if pV=constant and pV=nkT => NkT=const. You don't change Nk, well, T won't change either. So when you change V, p changes inverse proportional, N,k,T don't change at all.

This is only a special case stated as isotherm...I did not say T is constant. Of course (and even in an idg) the temperature increases whenever you compress a gas...The volume is reduced and the pressure is increased...afaik there is no real process where only pressure and volume change...an easy example is ice skating...you slide because the high pressure melts the ice directly under the blades...