Dichotomy’s non-random science questions.

[dichotomy]

Q16. Can Waterjet Cutting Technology produce a water jet that is hard enough to cut diamond? And to shape diamond?

 

13, no it is not a chemical fire but a nuclear fire. it only requires hydrogen.

 

Is there a known minimum (parts per million?) of hydrogen required?

[insane_alien]

no, it can occur between two single protons that just happen to collide with the tight energy.

 

Q16/ the jet will not be harder than diamond. water jets do not cut like a blade it uses pressure to force the material out the way.

[YT2095]

water jets do not cut like a blade it uses pressure to force the material out the way.

 

erm... how does a blade cut then?

[insane_alien]

well, the way he worded it seemed to imply that it was a blade dragged across the surface scratching it.

 

or maybe i just never thought it through.

[swansont]

Is there a known minimum (parts per million?) of hydrogen required?

 

If you want a self-sustaining reaction, then yes, you need a certain amount of gravity, which requires a certain amount of mass.

[Fred56]

Q. Do we know why there are three kinds, or states of matter (at least in the ordinary world) or is this like the atomic particles, we know about them because of observation, rather than the predictions of some theory?

[insane_alien]

yes we know why.

 

Solids: the bonds are strong enough to keep the atoms in roughly one place despite thermal motion of the atoms.

Liquids: intermolecular bonds are strong enough to keep the molecules in an amorphous mass but not strong enough to hold them in the one spot.

Gas: intermolecular bonds are feeble at best, they can neither hold molecules in one place or even keep them close together.

 

plasma: thermal motion is so strong electrons get ripped fro the parent atom by the force of collisions.

[Fred56]

Right, but there is no Theory of Bonding which tells us what any particular combination of elements will behave like. When a new compound (say a pharmaceutical) is made, its properties (melting point, IR spectrum, solubility, etc) are determined after the fact.

[insane_alien]

we can make a pretty good estimate. but it has a lot of factors involved. particularly because not all molecules are rigid. long chain molecules tend to be quite floppy.

[Fred56]

Ok, I'll try again. What I'm getting at here is that we know about bonding and how solids liquids and gases are the three most common forms of all matter, but this is because we have explained it empirically, rather than from any first principles of bonding, say, or any other known behaviour of matter. We still don't really know why matter comes in these three forms, do we?

[iNow]

We still don't really know why matter comes in these three forms, do we?

 

Philosophers and religion tend to focus on the "why," science tends to focus on the "how."

[Mr Skeptic]

Philosophers and religion tend to focus on the "why," science tends to focus on the "how."

 

Science also likes to know why. Knowing why something happens is a good step in knowing how it happens, and how related things happen. Consider that the concept of electric and magnetic fields led to the concept of electromagnetic waves. It works the other way around too; knowing how something happens is the first step in knowing why it happens. And why figures in the scientific method, see Occam's Razor.

[dichotomy]

no, it can occur between two single protons that just happen to collide with the tight energy.

 

Q16/ the jet will not be harder than diamond. water jets do not cut like a blade it uses pressure to force the material out the way.

 

In theory, can water alone be pressurized to the point of being able to 'cut' diamond? I’d imagine a harder than diamond material would be required for the nozzle.

The diamond nozzles used by water jets require periodic replacement, so logically this seems possible.

 

If you want a self-sustaining reaction, then yes, you need a certain amount of gravity, which requires a certain amount of mass.

 

So the mass is the quantity of hydrogen required for the sun to 'burn'?

 

Q17 If the circumference of the earth is massively extended; by a massive increase in water (could be over billions of years). What would be the more obvious results of this occurring? Would it affect earths orbit? Other planets orbits?

 

Q18 If water continued to rise above the surface of the earth, would water eventually dissolve the earth to the point that water was 99% and land matter (earth) 1%?

 

Q19 Could a sphere like object of consisting only of water exist, as a planet does, in space?

[Mr Skeptic]

The mass is just needed to keep the hydrogen from expanding and cooling, which would prevent it from ever getting hot and dense enough for fusion.

 

17 It would depend on where the water came from, or rather, its momentum when it hit earth. Yes, it would slightly alter other planet's orbits, perhaps even enough to destabilize them.

 

18 What do you mean, dissolve the earth? Enough water to cover most of the landmass? it would take an awful lot of water to dissolve all the solid matter on earth.

 

19 Yes, even a small amount of liquid water would form a sphere in space, either due to surface tension or its gravity. Lots of comets are made largely of ice.

[dichotomy]

18 What do you mean, dissolve the earth? Enough water to cover most of the landmass? it would take an awful lot of water to dissolve all the solid matter on earth.

 

 

By dissolve I mean turning all the land mass, right down to the earths core, into a liquid state. I'd imagine water increasing via the continuous work of bacteria and plants that make oxygen. I think it would be pretty cool if a planet was an entirely liquid eco-system. Like a clear fish bowl in space.

 

 

19 Yes, even a small amount of liquid water would form a sphere in space, either due to surface tension or its gravity. Lots of comets are made largely of ice.

 

So, theoretically a sphere the size of the earth could exist in space as only liquid? Or would it freeze?

 

Q20. Could planets in our solar system, at the core or foundations, possibly be burnt out stars?

[swansont]

So, theoretically a sphere the size of the earth could exist in space as only liquid? Or would it freeze?

 

Q20. Could planets in our solar system, at the core or foundations, possibly be burnt out stars?

 

If it orbited a star at the right distance it wouldn't have to freeze.

 

All of the planets are burnt-out stars, in the sense that they are the result of a second-generation supernova. However, I think they do not have a composition consistent with being the intact remains of a star.

[Mr Skeptic]

By dissolve I mean turning all the land mass, right down to the earths core, into a liquid state. I'd imagine water increasing via the continuous work of bacteria and plants that make oxygen. I think it would be pretty cool if a planet was an entirely liquid eco-system. Like a clear fish bowl in space.

 

You do know that plants don't make oxygen, just convert carbon dioxide into carbon and oxygen, right? And it would be insanely deep, so if you were a significant distance from the surface, it would be pretty dark.

 

 

So, theoretically a sphere the size of the earth could exist in space as only liquid? Or would it freeze?

 

Something slightly smaller than earth would have enough gravity to crush ice into a sphere.

[swansont]

Something slightly smaller than earth would have enough gravity to crush ice into a sphere.

 

Ah, good point. It wouldn't be entirely liquid.

 

 

Here is a phase diagram (1st link) and the pressure calculation (2nd)

http://www.lsbu.ac.uk/water/phase.html

http://www.grc.nasa.gov/WWW/K-12/Numbers/Math/Mathematical_Thinking/grvtysp2.htm

[dichotomy]

You do know that plants don't make oxygen, just convert carbon dioxide into carbon and oxygen, right? And it would be insanely deep, so if you were a significant distance from the surface, it would be pretty dark.

 

Ok, so not quite a clear fishbowl then. But a dark liquid.

 

Something slightly smaller than earth would have enough gravity to crush ice into a sphere.

 

I'm not sure if I follow here. Do you mean the resultant sphere would not be ice, but some other matter? Or, the resultant sphere would be a smaller ball of liquid? Or, something other?

 

Q21. Could two identical (size, weight) stars exist in the same solar system? Or, would they collide to form one star, or splinter to form smaller stars, planets, comets, etc?

[Mr Skeptic]

I had meant that a sphere a little smaller than the earth would have enough gravity to crush a bunch of chunks of ice into a larger sphere shape. This sort of thing figured into the recent defining of what a planet means; it was suggested that a planet had to have enough gravity to form itself into a sphere. Anyone know if they decided on what a planet means yet?

 

As swansont pointed out, if you made a large enough sphere of water, the gravitational attraction would produce enough pressure to turn the core solid ice, much like we have a solid metal core despite the temperature being hotter than its melting point.

[dichotomy]

As swansont pointed out, if you made a large enough sphere of water, the gravitational attraction would produce enough pressure to turn the core solid ice

 

[Fred56]

I think it might form something more exotic at the core, depending on how big the "planet" might get, like supersolid ice, whatever that might look like.

[dichotomy]

much like we have a solid metal core despite the temperature being hotter than its melting point.

 

So, the core doesn't become liquid metal because the rest of the earth acts as a heat sink of sorts?

[swansont]

So, the core doesn't become liquid metal because the rest of the earth acts as a heat sink of sorts?

 

No, it's because the melting point depends upon pressure. At high pressure you can have a solid, even though at atmosphere it would be liquid or even possibly a gas. You can see that in the water phase diagram (though for other materials the phase diagram may not be so complicated)

[insane_alien]

No, it's because the melting point depends upon pressure. At high pressure you can have a solid, even though at atmosphere it would be liquid or even possibly a gas. You can see that in the water phase diagram (though for other materials the phase diagram may not be so complicated)

 

the Carbon Dioxide phase diagram is usually used as an introduction for this. it has reasonable variations with pressure and is very simple to follow.