Ask something - We can help.

[arj0n]

InC,

As for the first scientific one:

Heat = atomic motion
vacuum = (almost) no atoms.
No atoms = no heat loss or warming up by conduction

So the hot soup stays hot and cools down very slowly because a perfect vacuum is nearly impossible.
But I guess that theoretically the hot soup stays hot as long as there is no conduction.

[zabnat]

2) Let's say there's no air on earth and I'm stanting ontop of mount everest or tallest skyscraper. I throw a baseball. Can I make it orbit earth? Would lack of air friction make my throwing speed high enough to achieve needed speed? Also, since there's no air friction in space, why do astronauts in suits move so damn slow?

The baseball would need a velocity of 8 km/s to make it to the orbit. Since there is no air the air drag doesn't deccelerate the ball, but gravity drag still does. So the ball would need to leave your hand with even greater velocity.
Maybe astronauts move so damn slow because their suits are so big and clumsy? Also, they want to be careful so they don't drift away from the spaceship/-station. That would be a sucky way to die.

[Anian]

Heat = atomic motion
vacuum = (almost) no atoms.
No atoms = no heat loss or warming up by conduction

So the hot soup stays hot and cools down very slowly because a perfect vacuum is nearly impossible.
But I guess that theoretically the hot soup stays hot as long as there is no conduction.

...then how do we get heat from the Sun here on Earth? Heat is not atomic motion in the sense it's the atoms, it's the energy that makes the atoms move/vibrate...it's not only energy waves, but it's EM waves - the ones that don't need matter/medium to spread...
Or did I just make an ass out myself?  

Yeah, about the gravity ball in orbit thing, as zabnat said, even though the speed is determined by the air friction very much, the forces that act upon the ball should be equivalent, well in the vertical direction (meaning that gravity and the part of centrifugal force that pushes the ball away from the center of Earth are same but in opposite directions), but there should be the part of the centrifugal force that moves the ball in the direction you threw it (so it moves "horizontally"). It's all in the vectors.  

While on astronauts thing - they should give them something like the ropes Batman uses for grapling (only maybe with some thing sticky or magnets at the end, so they don't damage the actual ship). They should have that on their arms so if the drift away they just point it at the shuttle and shoot...maybe they even have that.

[Calin Leafshade]

Heat has three methods of motion.

Conduction - which will not happen in a vacuum
Convection - which is due to varying densities, also not possible in space
and radiation - This is electro magnetic radiation which is how we get our heat from the sun.

The soup would cool down but very slowly...

As for the baseball; Air resistence is a fairly small force when considering something like a baseball. Even without air resistence you would need to apply about 5MJoules to the baseball. which is about 2.5 sticks of dynamite.

EDIT: actually now i think about it, im wrong about the soup.

The soup would freeze.

Conduction has quite a small effect on heat transfer. Most of the heat loss is done by radiation, which is still affected by differential temperature gradients.. therefore the soups days are numbered. since its like 3-4K in space.

Conduction in a gas is really quite small.. think about touching something metal which has been in a room for along time.. its still cold.

[Jared]

While on astronauts thing - they should give them something like the ropes Batman uses for grapling (only maybe with some thing sticky or magnets at the end, so they don't damage the actual ship). They should have that on their arms so if the drift away they just point it at the shuttle and shoot...maybe they even have that.

The trouble with that idea being that Batman uses one in a situation where there's gravity and a clearly defined 'up'. Because the grapple pulls him away from the Earth's gravitational pull it's easy for him to stop. In a Zero-G environment, once you accelerate you need to apply an equal force to stop yourself moving which is basically asking astronauts to pick up over their own body weight. End result - astronauts slamming into the ship's hull and it becomes a contest as to whether the suit or the ship takes the worst/most expensive damage.

Tools don't work predictably in space. They found early on that a drill used in Zero-G would actually cause the astronaut to spin around at great speed, for example. A lot of the way things work mechanically here on Earth is due to our gravity and we don't take it into account.

[Ultra Magnus]

While on astronauts thing - they should give them something like the ropes Batman uses for grapling (only maybe with some thing sticky or magnets at the end, so they don't damage the actual ship). They should have that on their arms so if the drift away they just point it at the shuttle and shoot...maybe they even have that.

The trouble with that idea being that Batman uses one in a situation where there's gravity and a clearly defined 'up'. Because the grapple pulls him away from the Earth's gravitational pull it's easy for him to stop. In a Zero-G environment, once you accelerate you need to apply an equal force to stop yourself moving which is basically asking astronauts to pick up over their own body weight. End result - astronauts slamming into the ship's hull and it becomes a contest as to whether the suit or the ship takes the worst/most expensive damage.

Not necessarily.
You're assuming it must include the rope-retracting mechanism, but it doesn't have to.
The astronauts could just pull the rope by hand once it's attached.
They could probably even still include the retracting mech if they made it sufficiently weak.

Tools don't work predictably in space. They found early on that a drill used in Zero-G would actually cause the astronaut to spin around at great speed, for example.

Even if that astronaut was anchored to the rest of the shuttle in some way?


Edited out rather condescending pic.
Sorry, I mis-read your post. Upon re-reading, it's clear I didn't need to explain that to you.

[Jared]

The astronauts could just pull the rope by hand once it's attached.

At that point they'd have basically exactly the same mechanism that they have now..

[Ultra Magnus]

Well, in that case...

While on astronauts thing - they should give them something like the ropes Batman uses for grapling (only maybe with some thing sticky or magnets at the end, so they don't damage the actual ship). They should have that on their arms so if the drift away they just point it at the shuttle and shoot...maybe they even have that.

They do.

Fixed that for you.

[arj0n]

Heat = atomic motion
vacuum = (almost) no atoms.
No atoms = no heat loss or warming up by conduction

So the hot soup stays hot and cools down very slowly because a perfect vacuum is nearly impossible.
But I guess that theoretically the hot soup stays hot as long as there is no conduction.

...then how do we get heat from the Sun here on Earth? Heat is not atomic motion in the sense it's the atoms, it's the energy that makes the atoms move/vibrate...it's not only energy waves, but it's EM waves - the ones that don't need matter/medium to spread...
Or did I just make an ass out myself?  

well, atomic motion gives also vibration which leads to invisible Infrared Radiation, that's how we get heat from the sun here on earth.
When infrared is absorbed, it results in atomic motion, and therefore, in a rise in temperature.
And no, you didn't make an ass out of yourself

[Jared]

A (somewhat) interesting note from that is that the assumption that it's cold in space is actually wrong. The best known astronauts from our missions are in danger of freezing if outside the capsule for too long, but that's because their missions have been deliberately run when the Earth is between themselves and the sun to give them protection. A book I read stated that in direct sunlight the temperature of space is literally boiling.

[m0ds]

@Mods:

Step 1

Step 2

You're welcome! 8)

Thanks.

But sadly, for some reason, this computer won't allow me to record my stereo out mix. But thanks for the links

[arj0n]

Mods, I've upped the Summer Heights High Theme here's if still needed.

Specs:
Format: MP3
Duration: 07:44
Quality: 44kHz, 320 kbps, Joint Stereo
Size: 17,73 Mb

[zabnat]

This has bugged me couple of days now.
If I had bucket of room temperature water (10 liters), would it be possible to cool an object (like a rock) so cold that it would freeze all the water in the bucket. Let's say the bucket would be 20 liters so no water would escape even if the object would displace 10 liters. So how cold the object would have to be? How big would it have to be? What material would it have to be?

[Calin Leafshade]

hmmm.. You would need to put something in that, once the temperatures had equalised, would be colder than zero degrees.

So to entirely freeze a bucket of 10 litres of water you would need to remove about 1kJ of energy I think (MCdT)
so the object you put in would need to have at least 2kJ LESS thermal energy than the water.. which is nothing really.
(it takes about 3kJ to boil water)

As for the exact temperature and material i have no idea since i dont have the specific heat capacity of loads of materials available.

It's actually not possible to calculate the total thermal energy of a system since a 'perfect' gas doesnt exist. Any changes in temperature result in phase changes which screws everything up. Thats quantum physics for you.

I reckon a lump of anything cooled to about -50 and of equal mass to the water should do it easily. Assuming perfect conditions.

[Creed Malay]

 How do Crane Flies survive? Seriously, they are useless - they can barely fly, and those insanely long legs don't seem to have any real point to them at all. They're rubbish, but they seem to do alright - they're everywhere at this time of year. What is those guys deal? How come they haven't been eaten into extiction by birds by now?

[Calin Leafshade]

frasier crane sends them food parcels.

[arj0n]

If there is one animal I hate it is definitely the (female) mosquito.
Is there any usefulness of there existence beside being food for fish?

[monkey0506]

Dear something,*

Firstly thank you all for what you have done and are doing. I have recently encountered a situation which may call for your specialist services. I recently have discovered that on my personal computer games from TellTale Games seem to be leaking memory in much the same way that Niagra Falls leaks water.

I can't seem to figure out why this would be, and so I'm just seeking answers here. Any and all help you can provide would be much appreciated. My system specs and original reference for this question may be found here.

Thanks again,

monkey

*The subject clearly says, "Ask something". So that's what I'm doing. I'm asking something a question. Got a problem with that?

[Abisso]

This has bugged me couple of days now.
If I had bucket of room temperature water (10 liters), would it be possible to cool an object (like a rock) so cold that it would freeze all the water in the bucket. Let's say the bucket would be 20 liters so no water would escape even if the object would displace 10 liters. So how cold the object would have to be? How big would it have to be? What material would it have to be?

I usually think about situations at the "limit" to solve this kind of problems. So let's cool a bucket of water till about (just a bit more than) 0° C. Then it's quite obvious that putting an object with an adequately lower temperature will suffice to freeze the water. Exact temp and mass of the object I don't know, but it's surely possible, under certain conditions, as long as you don't put restrictions on the mass and temperature of the object. Real life restrictions could probably involve the lower temperature easily achievable. I believe you can use liquid nitrogen to reach really low temps.

P.S. Objects actually happen to freeze water even as we speak: never noticed how the ice is usually found over car's windows, even when puddles aren't frozen?

[Scarab]

Conduction in a gas is really quite small.. think about touching something metal which has been in a room for along time.. its still cold.

Actually, all objects sitting long enough become 'room temperature', and the reason metal or tiles feel cold to the touch is because they are good conductors. The sensation of the coldness is due to a large amount of energy from your hand being transferred to the other object quickly (so we do not so much feel the 'coldness' but we feel 'negative' heat). This is because the human body is not good at quantifying things, just good at comparing them. e.g. If you put your left hand in cold water, and your right hand in hot water, then put them both in a bowl of warm water, your right hand will feel cold, and your left had will feel hot. Or you can only smell something in a room for a few seconds until your brain accepts this as the 'norm' and stops processing it.

So a metal object which has been in a room for a long time is not still cold, it just heats up really quickly.

S.