Vacuums in a vacuum?

Me and my friend we talking in Geography lesson and our conversation turned to space and we talked about the effect a vacuum would have on a vacuum cleaner. He thinks it would implode, though i think it would explode. which one of us is right?

What would cause it to do either?

Sounds like you were having a challenging lesson today.
Well, since there is no air for the 'vac to suck up, it would do precisely nothing. Of course, the engine would still be running, and with no air around to allow convection or conduction, it would only be able to lose heat via radiation. The motor would heat up, but wouldn’t burn (no air 'natch). Eventually, any plastic in the motor would melt causing a nasty mess (but no nasty smells in a vacuum of course). I guess the next step would be that any soldered joints in the motor would melt - at which point the 'vac would just stop working.

Of course, in space you would also have to consider the lack of gravity …

I thought the air inside of the vacuum would try to get out as in nature abhors a vaccuum and it would try to escpe so fast that it’d explode. mayB Im wrong but thats what SD is for, proving Im wrong

*I thought the air inside of the vacuum would try to get out as in nature abhors a vaccuum and it would try to escpe so fast that it’d explode. mayB Im wrong but thats what SD is for, proving Im wrong *

You mean the air in the bag and mechanisms, right? If you tossed a vacuum cleaner out a space shuttle airlock, I’d imagine the air would just escape out the path of least resistance. Without the motor running, there’s very little to keep air from flowing one way or another. It’d probably just escape out the main intake, flowing past the motor turbines without much of a problem.

A vacuum cleaner works by lowering the air pressure inside it. The air outside the vacuum pushes itself in because it is high pressure air and the vacuum cleaner has low pressure air. The air pushing into the vacuum cleaner will carry with it all the hair and dirt and crud.

So, a vacuum cleaner could not work in a vacuum, since there is no outside air that would push itself in. When you turn on the fan, all that happens is that the blades rotate…but since there is no air, the blades have no effect. Eventually I suppose the vacuum cleaner might get hot enough to melt, but it’ll probably be a long time til that happens.

As posited before, the vacuum cleaner would simply float there, running silently.

As to whether or not it would melt…that depends upon whether or not it was in the sun or not. If so, and without protection (of course, you could design reflective shielding for it) it would melt without any assistance from you. If it were out of the sun’s rays, the heat-sink effect of space would probably keep it cool enough, if not too cool. This is rudimentary physics here, but still way out of my league, so if someone else has deeper understanding, please let me know.

The question is: how do you plug the thing in? Does the Shuttle have one of those outdoor-type outlets on the side? I suppose it should. And remember: In space, no one can hear you scream “This carpet is filthy!”

Thank you, and goodnight.

a very long extension cord :smiley:

Colin:
Yes, smells do exist in a vacuum. Smells are just volitized chemicals, aka gases. So you would pump a thin gas into the vacuum as the plastic vaporized. Wouldn’t affect much, granted, but it would exist.

et alii:
Pretty much correct. If the vacuum cleaner was running with air in its bag as you tossed it out the airlock, the engine would be ruined as the contents of the bag bent the fanblades on the way out. If you shut off the engine, it would be perfectly usable afterwards assuming nothing was ruined by the temperature extremes (space gets very hot and very cold).

Most of the motors used in vac’s are in fact air cooled by the air flowing through. What will happen is that the small amount of insulation that covers the windings of the motor will heat up and quickly fail causing the motor to come to a quick stop. Small amount of particulate with a smelly aroma released but without air to buoy or the movement of the fan it will fall rapidly to the floor if in an enclosed space due to the effect of gravity.

Notes that I am not a “scientist”, but I did stay in a Holiday Inn Express last nite :smiley:

If we ignore the extension cord and assume a battery powered 'vac, then another problem arises. The motor is a kinda rotary thing spiniing at high speed. And it’s in the vucuum of space. Newton’s third law will require an equal an opposite reaction. So the rest of the 'vac will start to spin in the opposite direction to the motor. And with no air resistance to slow it wiil eventually spin around at the speed of light! Maybe :confused:

Try agaim, my friend. It will never spin faster than the motor origionally did…Also assuming that the overall weight (mass) of the entire vac is less than that of the rotor in the motor…

About this speed of light thing. I remeber in my physics class we used to play with these fan cars. Basically four wheels with a fan attached. You flipped the switch the fan went on, and the car was moved foward via Newtons third law. Now if the fan car was allowed to run on an infinitely long track, and the batteries would never run out would it eventually reach the speed of light?

I guess the cleaner will eventually come to a staedy spin speed.

The car won’t reach warp speed. Either atmospheric drag will eventually either stop it at a steady speed, cause it to break up or possibly melt the super powered elastic band.

If you set it off in the vacuum of space, it will spin like its friend the vacuum cleaner (no air to push against in space)

You all seem to be forgetting one simple thing. Unless this particular vacuum cleaner is specifically built to function in an ultra low pressure environment (outer space), namely it is built out of all-metal and low outgassing components (delrin, teflon, kapton and cal-rez), the thing is going to deform almost instantly.

For the nonce, we’ll ignore the fact that in outer space one side of the vacuum cleaner would be at several hundred degrees in the sunlight and the other side facing away from the sun would be at a few hundered degrees below zero.*

Ever put a common, plastic handled screwdriver in a vacuum chamber and pump it down? Ordinary styrenes and other polymers tend to outgas dramatically. That is, the solvents remaining in the plastic tend to expand if the are given the chance. Without any air pressure around, a lot of plastics literally balloon at reduced pressures.

Your everyday, off the shelf vacuum cleaner might function for a few seconds before the motor housing warped and deformed beyond functional limits. The pressure drop created across the inlet and outlet of your typical vacuum cleaner is only so many negative inches of mercury as seen on a barometer. The vacuum of outer space is measured in microns (millionths of a meter) of mercury. Consequently, you would not be able to detect any measurable displacement of gas (atmosphere) due to its operation (however brief that might be).

Vacuum pumps used to attain the low pressures of deep space in test chambers typically have a throughput on the order tens of thousands of liters per second. Even the roughing pumps that perform the primary evacuation of sea level pressure atmosphere from these chambers operate in the ten or hundreds of liters per minute realm. Simply put, your average vacuum cleaner does not qualify for this discussion.

Needless to say (than why am I saying it?), you would see absolutely no effect whatsoever. Yes the motor might overheat from the distortion of its housing, but not much burning is going to occur without any atmosphere around to provide the oxygen. Few household appliances are manufactured with materials that provide their own oxygen when burned. Something tells me that UL Laboratories might take a dim view of that. The electrical energy being dissapated by the stalled motor might vaporize some of the insulation before the windings fused open at some point. However, the principal failure mode would probably continue to be the alteration of dimension tolerances (i.e., change of shape).

So unless you brought some thermite to help things along a bit, it’s my SWAG that you’re Sh!t Out Of Luck!

  • In order to overcome the enormous and destructive stresses that this temperature imbalance induces, the space shuttle is frequently put into rotisserie mode. The craft is slowly rotated to maintain a relatively even surface temperature over the body of the shuttle.

Wow! Thanks for all your contributions. Looks like once again Burnt Toast is proven wrong :slight_smile:

Is this the technical term?

Even though the OP mentions space the actual inquiry is about the effects of a vacuum on a vacuum cleaner, and not about what would happen to a vaccuum cleaner if you flung it out of the space shuttle. All the posts about the heat of the sun, or a vaccuum spinning wildly in freefall are irrelevant if the vaccuum is sitting on the floor in a man made vaccuum chamber on Earth.

I don’t know why I felt the need to point this out.

Zensters point about the low-outgassing components is valid no matter where the vacuum is. The vacuum wouldn’t explode or implode, but the majority of the non-metal components would be altered in ways that would make the vacuum cleaner forever unusable.