how do space rockets work?

[Smike]

Okay, obviously there's all that flame and smoke and stuff, but how does that result in upwards motion? And what stop them falling over on the way up?

'for every action there is an equal and opposite action' what's being squirted out the back? does the heat count?

Incidentally, for people who think this is to easy or dull to comment, how does a biro work? there's ink or something in the plastic tube, but how does it know to come out? is there a valve or what?

 

[LuxFerum]

You can find some useful information

For rockets here ,
And for pens here.

 

[Bikewer]

For many years, even scientists debated as to the possibility of rockets working in vacuum. It was felt that the rocket exhaust needed something to "push against".

But the most basic of Newtonian physics provided the answer.


As I recall, that was one of the big complaints of the guy who wrote "The Physics of Star Trek". He felt that the Warp engine was simply a technological achievement; that there was already some science to indicate that we could cheat the speed of light.

But the "Impulse" engines would require some sort of reaction mass. In order to manuever the Enterprise, you'd need a really big fuel tank.

 

[davidhorman]

But the "Impulse" engines would require some sort of reaction mass.

What's he basing that on? "Impulse engine" is just a name - I don't think how they work has ever come up in the show.</nerd>

What annoys me is that when they disable a ship's engines, it stops dead in space.

David

 

[ceptimus]

They have 'explained' things - but it's different 'explanation' every time - they just have a scriptwriter string some technical terms together.

Captain, if I bypass the quantum flux capacitors, and modulate the positronic matrix with a P-band neutrino wave, we may just be able to catch those devils!

 

[epepke]

Okay, obviously there's all that flame and smoke and stuff, but how does that result in upwards motion?

Assuming your not joking, it's the hot gas flying away from the rocket.

It all comes down to the center of mass, for a Newtonian approximation of rocketry anyway.

And what stop them falling over on the way up?

For an ideal rocket, it doesn't matter where along the axis the thrust is. Of course, real rockets aren't ideal. So they have gimbals on the engines and computers to turn them just a bit to get the right thrust.

Incidentally, for people who think this is to easy or dull to comment, how does a biro work? there's ink or something in the plastic tube, but how does it know to come out? is there a valve or what?

There's just a ball, and the ink wets one side of the ball, which rolls when you're writing.

 

[Bikewer]

Hehe- I recall seeing an interview with one of the Next Generation actresses; who told several alumni that she'd been hired.
They told her, "Don't let them put you in engineering, you'll have to memorize pages of scientific gobledygook!"

Naturally, she was made an engineer....

 

[pupdog]

And what stop them falling over on the way up?

In the old films of early work, you see a lot of them falling over. Even today there have been costly failures when a rocket's attitude has screwed up. If you release an inflated balloon (with the end untied), where will it go?

 

[Smike]

Assuming your not joking

okay, now i feel really stupid.

On the plus side, i have let you all feel very superior.

Originally posted by epepke

There's just a ball, and the ink wets one side of the ball, which rolls when you're writing.

wow, smart. (no sarcasm, it actually is a great idea)
apparently they were first used in WW2 so pilots could write at different angles (why they’d want to write upside down I don’t know)

incidentally, while I was playing with a biro to test your explanation (I couldn’t see the ball, but I believe you anyway), I noticed another smart thing:

the retracting mechanism!

See for yourself. Get a retractable biro and click it few times. Faster! Keep going! Okay, that’s annoyed everyone within a few metres of you. Assuming you haven’t been sacked, look at the way it works. On mine a little spindle turns every time the button goes in, alternately stopping the pen bit from retracting, then letting it. Now that’s smart!

 

[Bikewer]

Not stupid at all. Many of us use all sorts of technology every day without any real idea of how it works.

Take that car you drive. How many folks out of a hundred or so could articulate how the internal combustion engine functions?

 

[epepke]

okay, now i feel really stupid.

It's not at all stupid. But sometimes we do get trolls in here, and I always get annoyed when this happens.

wow, smart. (no sarcasm, it actually is a great idea)

The best ones nowadays have pressurized cartridges. Çåpillary action and atmospheric pressure only goes so far.

Which leads to one of the dumbest urban legends in history, but there's no reason to pollute the thread with it.

In the US, we call them ball points. If you look very closely, you'll see that the point is a cone at the end. This is a shell, and at the very end it's crimped around a little ball.

See for yourself. Get a retractable biro and click it few times. Faster! Keep going! Okay, that’s annoyed everyone within a few metres of you. Assuming you haven’t been sacked, look at the way it works. On mine a little spindle turns every time the button goes in, alternately stopping the pen bit from retracting, then letting it. Now that’s smart!

Yes, the retracting mechanisms on pens are an excellent example of an elegant design. Although I think this was invented later. Back in the 60s, rectractable pens were quite expensive, suggesting that maybe a patent on the mechanism hadn't expired.