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Anonymous Poster

Helium Lifting Power with PSI

02/08/2011 1:27 PM

I was just given the "Egg Drop" project in my physics class and I want to house the egg in a container that will nearly float, so that it will have a very slow decent.

The box must be 20x20x20 cm or less, and the weight of the egg is about 60 grams.

What material should I use for the box and how much helium (at what psi) should I use??

I need to know how much helium I use, so I can't just keep filling it until it floats.

Let me worry about getting the helium IN the box along with the egg.

Thanks to all answerers in advance.

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#1

Re: Helium Lifting Power with PSI

02/08/2011 1:33 PM

We don't do homework here.

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Anonymous Poster
#6
In reply to #1

Re: Helium Lifting Power with PSI

02/08/2011 1:55 PM

This is in no way homework...

I am merely trying to find how much Helium compressed into a 20x20x20 cm. cube capable of lifting over 65 grams would weigh.

I know almost nothing about lifting power nor pressure, so I was hoping to find someone on here that would be kind enough to explain this to me.

I'd be happy to even know HOW to do it, let alone what the answer is.

So please don't assume i'm just looking for an easy answer to my homework. I'm not expected to know this stuff.

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#8
In reply to #6

Re: Helium Lifting Power with PSI

02/08/2011 2:00 PM

You can't do it.

It can't be done. Don't you get it???

It won't work.

You obviously have no concept of buoyancy, displacement or courtesy.

He has weight, so the more you cram in the heavier your (too small) box is.

"I was just given the "Egg Drop" project in my physics class " sounds like homework to me.

Do some research. Maybe Google "helium".

Your job is to learn, not have someone give you the answers.

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Anonymous Poster
#12
In reply to #8

Re: Helium Lifting Power with PSI

02/08/2011 2:14 PM

So you're saying that no amount of He or H will cause a box to float...??

Also, I'm a junior in high school that has an A in AP Calculus, an A in Physics B, and an A in AP Chemistry (among other classes), so I would appreciate it if you didn't act as if I was an idiot and rather act as if I am a student trying to find an answer to a question.

I have never had a class that discussed this subject, nor am I expected to know this. My question is referring to an original and creative idea that I have in mind to accomplish this project that I received today. At this point I am considering all ideas.

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Anonymous Poster
#13
In reply to #12

Re: Helium Lifting Power with PSI

02/08/2011 2:17 PM

Edit: Also, this project has nothing to do with buoyancy or displacement or any of that. I am MAKING it a project that has to do with that, and I do not know very much on the subject, so I came here for some answers first.

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#16
In reply to #12

Re: Helium Lifting Power with PSI

02/08/2011 2:21 PM

The first concept you need to master is that both H and He are heavier than nothing.

They are just lighter than air. So, take your A'ss and do some research on the relative density of gasses.

Why do you think blimps are so big? Consider the concept of a hot air balloon. What makes it float? A difference in density that imparts buoyancy to the body.

Forget it, it ain't worth it. Do you bully your parents, too?

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#18
In reply to #16

Re: Helium Lifting Power with PSI

02/08/2011 3:26 PM

I suspect his parents may be of the sort that are bullying the public school systems into teaching everything but what is practical or valuable knowledge to have in life. You know that real, math, science, physics, chemistry, and general understandings of the fundamentals of how things actually work.

That doesn't make him lazy or rude just poorly informed and misguided about what actually relates to what he wants to know. Or he could just be another one of those kids who was taught that his self esteem is more important than being right or useful.

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Anonymous Poster
#26
In reply to #18

Re: Helium Lifting Power with PSI

02/09/2011 12:40 AM

Naaah. You are too kind. Admit it. He's a freekin idiot. And lazy and rude.

How can anyone claim to have an A in physics, and claim to know about buoyancy, but be unable to do a simple buoyancy problem. We could blame the teacher, but only if his school does not have textbooks, where these answers are easily found.

I'm frightened for our future.

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#42
In reply to #26

Re: Helium Lifting Power with PSI

02/09/2011 2:15 PM

I take you have not spent much time around the schools, colleges and universities of today.

You don't have to know or learn anything about your given subjects class title to get a good grade you just have to be able to test well on what ever they tell you in that class to get a good grade.

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Anonymous Poster
#35
In reply to #16

Re: Helium Lifting Power with PSI

02/09/2011 8:17 AM

CR4 ADMIN: Deleted Post

Abuse/Attack: This post was deleted because it was an attack on another user. Please review the CR4 Site FAQ and the CR4 Rules of Conduct.

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#43
In reply to #35

Re: Helium Lifting Power with PSI

02/09/2011 2:44 PM

I assume this came from our little tyrant genius.

Anybody know what he said?

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#44
In reply to #43

Re: Helium Lifting Power with PSI

02/09/2011 3:02 PM

Why do you want to know? Are you glutton for punishment or do you wish to ghoulishly gloat over what is likely just another hormone induced adolescent rant. I do not know what was said. I have no desire to know what was said.

I've had foolish moments myself on this forum. I know that you have, too. Let this one go.

How do you get a hormone? Don't pay her.

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#45
In reply to #44

Re: Helium Lifting Power with PSI

02/09/2011 3:44 PM

How do you get a hormone? Don't pay her.

How do you make a hormone?

Just hoping to be amused, that's all.

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#46
In reply to #45

Re: Helium Lifting Power with PSI

02/09/2011 3:48 PM

I can botch any joke.

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#47
In reply to #45

Re: Helium Lifting Power with PSI

02/09/2011 3:51 PM

Kick her in the knee.

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#50
In reply to #16

Re: Helium Lifting Power with PSI

02/09/2011 5:00 PM

you have no concept of good manners

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#55
In reply to #50

Re: Helium Lifting Power with PSI

02/09/2011 6:10 PM

Neither have I.

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#20
In reply to #12

Re: Helium Lifting Power with PSI

02/08/2011 5:27 PM

Well, you've managed to show that good grades do not necessarily equal a good education.

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#27
In reply to #12

Re: Helium Lifting Power with PSI

02/09/2011 12:55 AM

Wait. You wrote in post 9:

I know all about buoyancy.

Now, you suddenly know nothing about buoyancy. And you're asking us not to treat you like an idiot?

If it walks like a duck, and squawks like a duck...

I bet you were thinking that you could pressurize the box to above atmospheric pressure to get enough helium into it to lift the box and the egg.

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#39
In reply to #8

Re: Helium Lifting Power with PSI

02/09/2011 10:34 AM

Your job is to learn, not have someone give you the answers.

Maybe his aspiration is to be a project manager.

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#74
In reply to #8

Re: Helium Lifting Power with PSI

02/26/2016 11:35 AM

I read this threat & was rather surprised at YOUR rudeness lyn! Read back to how the Jr High kid asked the question and how YOU responded! What is a discussion forum for exactly? To bully Jr High kids so you can feel like a big man or is it for questions and discussions? Which is EXACTLY what he was doing. "We don't do homework here"? It is YOUR attitude lyn that needs adjustment. You're a SERIOUS bully and to a Jr High kid no less, that certainly inserts you into the LOSER department, BIG TIME!

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#49
In reply to #1

Re: Helium Lifting Power with PSI

02/09/2011 4:58 PM

why not ? you're childish in nature ?

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#56
In reply to #49

Re: Helium Lifting Power with PSI

02/09/2011 6:12 PM

So am I.

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#2

Re: Helium Lifting Power with PSI

02/08/2011 1:33 PM

The weight of room-temperature air in a 20x20x20 cm box is about 10 grams, so even if you substitute total vacuum for it, it still will come nowhere near to floating a 60-gram egg.

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#3
In reply to #2

Re: Helium Lifting Power with PSI

02/08/2011 1:35 PM

No, no, don't you just keep putting He in until it floats??????????

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#4
In reply to #3

Re: Helium Lifting Power with PSI

02/08/2011 1:38 PM

The bigger they come, the harder they fall!

Or, put 6 light-headed people in a basket, and don't bother to turn on the propane burner....

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Anonymous Poster
#7
In reply to #2

Re: Helium Lifting Power with PSI

02/08/2011 1:57 PM

This in no way answers my question... at all...

That's not even a helpful fact, and is common sense anyway.

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#53
In reply to #7

Re: Helium Lifting Power with PSI

02/09/2011 6:04 PM

Are you the original poster?

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#54
In reply to #53

Re: Helium Lifting Power with PSI

02/09/2011 6:05 PM

Yeah.

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#5

Re: Helium Lifting Power with PSI

02/08/2011 1:50 PM

Ok first, you should know how an all metal boat floats in water? If you don't, look it up. This is the principle you are trying to use. Second you must discern at STP the mass of air that occupies your maximum box size. Third, wait a minute... Those two hints should be more than enough for you to do this work. Go earn you grade.

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#9
In reply to #5

Re: Helium Lifting Power with PSI

02/08/2011 2:02 PM

I know all about buoyancy.

Too bad this experiment isn't happening in water...

Also, I know that the box size will be 8,000 cubic centimeters. Knowing this gets me nowhere since I don't know how much helium lifts compared to air.

Those "hints" are not helpful in any way.

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#11
In reply to #9

Re: Helium Lifting Power with PSI

02/08/2011 2:08 PM

1,000 CM3 is one litre.

8 litres of STP (standard temperature and pressure) air weighs around 9.6 gm.

With this 8 litre volume constraint, the limit of bouyancy is...

Please, what physics class are you participating in? In what capacity?

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#14
In reply to #9

Re: Helium Lifting Power with PSI

02/08/2011 2:19 PM

You are absolutely correct! For you those hints are not at all helpful. I'm very disappointed, but not surprised. Well if you can't figure out the lifting capability from a completely theoretical approach, maybe you could figure out an empirical way to measure the lifting capability of helium.

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#17
In reply to #9

Re: Helium Lifting Power with PSI

02/08/2011 3:08 PM

Wrong again. You evidently don't know anything abvout buoyancy, and so far you are being much too stubborn to learn.

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#21
In reply to #9

Re: Helium Lifting Power with PSI

02/08/2011 8:36 PM

Keep looking Padwan! It is indeed about buoyancy!

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#22
In reply to #9

Re: Helium Lifting Power with PSI

02/08/2011 11:14 PM

roughly 1.218 oz per cubic foot.

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#24
In reply to #9

Re: Helium Lifting Power with PSI

02/08/2011 11:41 PM

What do YOU call a helium balloon, other than a buoyant object?

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#41
In reply to #9

Re: Helium Lifting Power with PSI

02/09/2011 12:59 PM

The basic concept you need to understand is that buoyancy is not limited to water. Buoyancy is the weight relation between two masses of the same volume. A boat floats in water because is weighs less than an equivalent volume of water. A blimp floats in air because it weighs less than an equivalent volume of air. A cannonball floats in mercury because it weighs less than an equivalent volume of mercury.

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#10

Re: Helium Lifting Power with PSI

02/08/2011 2:03 PM

Once you start compressing the helium it will be getting more dense, losing it's lifting capability.

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Anonymous Poster
#15
In reply to #10

Re: Helium Lifting Power with PSI

02/08/2011 2:20 PM

Thank you!

...finally something helpful and someone not being a complete ass about my lack of knowledge on this subject.

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#34
In reply to #15

Re: Helium Lifting Power with PSI

02/09/2011 7:04 AM

It's not your lack of knowledge: it's you lack of desire to think about what buoyancy is really about that is the problem.

http://en.wikipedia.org/wiki/Buoyancy

http://en.wikipedia.org/wiki/Helium_balloon

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#19

Re: Helium Lifting Power with PSI

02/08/2011 3:39 PM

If you really must continue this experiment, for heavens sake be careful!

I still haven't recovered from the last experiment.

Thank you,

H. Dumpty

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#23

Re: Helium Lifting Power with PSI

02/08/2011 11:39 PM

Well, Guest with high grades, I'd take a different approach. What the folks are trying to say is that although your 8000 cc of helium at room pressure and temperature is lighter than the volume of air it displaces, it isn't sufficiently lighter. It will only contribute 10 grams of lift. Therefore, even if you want it to work, it's physically impossible. Now, I'd try an experiment where the box went down spinning, which greatly increases the apparent area of the box, and then convert the spinning momentum to lift by changing the angle of attack of the propeller. It HAS to work, because I just thought of it, and no one else has!

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#58
In reply to #23

Re: Helium Lifting Power with PSI

02/09/2011 7:25 PM

This thread veered down a kind of whacky but interesting road. I like your over-unity/perpetual motion remark, and am giving you a GA just for that (especially the "and no one else has" part)! I reeeeeaaaaly like spinning boxes; they're sooooo cool!

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#25

Re: Helium Lifting Power with PSI

02/09/2011 12:13 AM

You just need about a half pound of "upsidasium" that should do it.

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#31
In reply to #25

Re: Helium Lifting Power with PSI

02/09/2011 3:27 AM

I should point out that upsidasium has negative weight (upsidasium is unique in that it's mass is a vector quantity). Consequently, you should not attempt to measure out a half-pound of Dn on ordinary bathroom scales without first affixing them to the ceiling.

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#66
In reply to #25

Re: Helium Lifting Power with PSI

02/10/2011 5:51 PM

That's a good 'en!

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#28

Re: Helium Lifting Power with PSI

02/09/2011 1:11 AM

For anything beyond atmospheric pressure, the more helium in the box, the worse the buoyancy gets. At atmospheric pressure, the weight ratio for helium (He) to air is about 4:29.

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#29

Re: Helium Lifting Power with PSI

02/09/2011 1:22 AM

I tried the 'sperimint, but got HE in the lungs, skwawk!! cool ixspirimint!! Ha Ha funnee!!

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#30

Re: Helium Lifting Power with PSI

02/09/2011 1:41 AM

Hello Guest, Helium balloons float in air because the balloon/helium combination is less dense than the volume of air the balloon displaces (near ground level. Aloft things become a little more complicated). Now, adding more helium (whilst keeping the volume constant, as your box would do - in theory) would *not* make your box more inclined to float. On the contrary. Helium has mass, too, you know, and the more helium you put in your container (which we assume has a fixed volume), the more your box will _weigh_. Truly, Guest, the lightest thing you could put in your box is ... nothing at all. A pure vacuum. Think about it why a vacuum would work best. Why? A vacuum has no mass. Zero. Nada. It doesn't get any better than that! Unfortunately, Guest, one cannot inflate an ordinary balloon with pure vacuum and expect it to keep it's shape for long. A rigid container on the other hand might work - provided the container, when evacuated, and its payload are together less dense than an equal volume of air. Take heart, Guest, this isn't at all complicated. Not really. But, as this is *your* project, I leave to *you* to do the math. It's only fair. ~G2 ('Guest II')

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#32

Re: Helium Lifting Power with PSI

02/09/2011 6:23 AM

Hi Guest,

A box with 0.2m sides has a volume of 0.008m3

Air has a mass of about 1.2kgm-3

The air displaced by your box has a mass of about 1.2 kgm-3 x 0.008m3 = 0.0096kg = 9.6g

If you could find an extraordinarily strong, essentially massless material to build your box out of and you could "fill" it with a vacuum you could lift 9.6g. What's the mass of your egg? I'm guessing 50g?

So you would need a box about 5 times bigger to lift your egg if you could fill it with vacuum. You can't though, so you need to find the mass 0.008m3 of the lightest gas you have available and subtract that from the 9.6g. Maybe you'll end up with an uplift of about 5 or 6g. Now you need a box about 10 times bigger to lift your egg. Now you may not have access to large quantities of graphene sheeting, so you may also need to subtract the mass of your box.

I'd say you're back to the drawing board.

Maybe use hydrogen and let it drop fast. Then just as it's about to crash into the floor, light that baby up and come in softly on rocket boosters - that'd float my boat if I was your science teacher.

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#33
In reply to #32

Re: Helium Lifting Power with PSI

02/09/2011 7:01 AM

You mean "float your box", right?

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#60
In reply to #33

Re: Helium Lifting Power with PSI

02/10/2011 5:13 AM

Egg-zactly.

(Groan)

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#36

Re: Helium Lifting Power with PSI

02/09/2011 8:24 AM

Basically, what everyone is trying in a not so very polite way of telling you, is that you would need a MUCH larger box if you plan to use helium. I had the same project in high school. I filled the bottom of the box with crumpled up physics notes, and put the egg on top, thinking the shear power of the physics formulae on the paper would support the egg. It worked.

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#37

Re: Helium Lifting Power with PSI

02/09/2011 9:52 AM

How 'bout emptying the egg? after all the result of your "egg drop" is to not break the shell isn't it?

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#38
In reply to #37

Re: Helium Lifting Power with PSI

02/09/2011 10:05 AM

If you're going to cheat, go with a hard boiled egg.

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#40

Re: Helium Lifting Power with PSI

02/09/2011 11:30 AM

You seem to have a glimmer of the basic need here which is to limit the deceleration upon impact. With bouyancy you are barking up the wrong tree. Think instead of surviving an automobile crash. Same principle.

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#48

Re: Helium Lifting Power with PSI

02/09/2011 4:40 PM

Now wait a minute... I keep a cylinder of compressed helium in my shop. It is pressurized to about 2500 psi. Naturally since there is so much helium in the cylinder I keep it strapped to an elephant to keep it from floating away. So in addition to the expense of the helium (and the elephant) I have to factor in the cost of the hay for the elephant each month, as well as the salary of the guy that cleans up after the elephant. I have considered going in halves with the local zoo to recoup some of my expenses. Are you saying I could just let the elephant go free (late one night obviously) and the cylinder of helium would just sit there on the floor?!

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#51

Re: Helium Lifting Power with PSI

02/09/2011 5:23 PM

as a brain storming exercise and in no particlar order:

- empty the egg by putting a small hole in both ends and blowing out the contents

- use a balloon filled with the helium (or indeed air) and use the jet propulsion from the balloon to slow the descent

- the "box" can be the required volume to begin with but can develop into a parachute

- does the egg need to be in one piece when it lands ? if not, you could just drop it

- try to use a circular energy storage system (make the egg swing in a circle at the end of a string) with some kind of wing at the other end which would give you lift to counter the gravity loads

- compress the helium by a factor of 5 (compared to its normal volume) into the 20cm box and then let it go so that it jettisons the sides of the box to reveal a balloon that is 5 times bigger thereby making the whole thing slightly heavier than air

- a ping pong ball can be held steady in a hairdryer flow (look on youtube) ; why not put the 20cm box beneath the egg with a fan in it ? i know this doesn't quite work but maybe something else will

- can the 20cm box contain anything ? can it contain one of those model helicopters ?

- turn off the earths gravity for a couple of seconds. seriously. ask your techer to take a trip with you in a freefall plane

my teacher would always suggest using dynamite for any brainstorming idea, just so that everyone would loosen up.

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Anonymous Poster
#72
In reply to #51

Re: Helium Lifting Power with PSI

02/11/2011 12:51 AM

Silly Terrans!

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Anonymous Poster
#73
In reply to #72

Re: Helium Lifting Power with PSI

02/12/2011 5:26 PM

its the venutians you need to worry about. they have no sense of gravity.

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#52

Re: Helium Lifting Power with PSI

02/09/2011 5:26 PM

As the egg has a permeable shell, the introduction of helium would be detrimental to the development of the embryo, thus negating your attempts to hatch the egg, through body heat transfered by your hairy derriere.

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Anonymous Poster
#57

Re: Helium Lifting Power with PSI

02/09/2011 7:05 PM

Physics is obviously getting easier - last time I came across this, the cube was 100 mm. (~ 4", not ~ 8") and the drop 10m (33 ft), onto concrete (per tradition)

The the single survivor was then progressively tested up to ~43 m (~140 feet, 10th floor) and only eventually lost to a baseball bat.

No helium was harmed in the testing.

34.5

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Anonymous Poster
#59

Re: Helium Lifting Power with PSI

02/09/2011 8:31 PM

There is the possibility that a buoyancy exercise could be utilized in this experiment. As i recall from my class, the device had to fit inside the given dimensions before the drop, so as not to exclude parachutes and other such devices. If the original guest wished to they could deisgn a pressurised helium container which upon release would expand and thus become more buoyant and potentially balance out the weight of the container and the egg.

Just a thought!

(mental note, would a carboard box be able to contain 6 atmospheres of pressure?)

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Anonymous Poster
#62
In reply to #59

Re: Helium Lifting Power with PSI

02/10/2011 8:16 AM

Yeah, only if that box will be contained in another steelbox.

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Anonymous Poster
#61

Re: Helium Lifting Power with PSI

02/10/2011 8:13 AM

Two ways you can achieve your project,

1) Have this made at a zero gravity condition

2) Replace Helium with sand or wood chips etc.

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Anonymous Poster
#63

Re: Helium Lifting Power with PSI

02/10/2011 8:37 AM

The key to using helium in this project is to shift the reference point far enough to the left to allow the helium to produce 60g of buoyancy. A single stage vacuum pump simply will not get you there. Cascaded vacuum pumps will allow you to evacuate your container down to negative absolute pressure values. This will then allow you to introduce sufficient amounts of helium to provide 60g of buoyancy without having the weight of the helium cause a lifting problem.

Most people don't think of this. Be sure to include comments about this idea on your next test. It will let your teacher know how hard you work on homework.

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Anonymous Poster
#64

Re: Helium Lifting Power with PSI

02/10/2011 12:26 PM

Please don't forget to thank those here who were able to help you because, when it came to their turn, they did their own homework themselves. These days it's the grade - not the education - that matters, is it not? You must be very pleased.

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Anonymous Poster
#65

Re: Helium Lifting Power with PSI

02/10/2011 3:51 PM

Congratulations, young padwan, you have made the 'Recent Active Threads' list. A thing that not all of us accomplished Jedi have done.

I would ask that all of us accomplished Jedi go easy on the kids. College students are one thing, but a high school student?! Come on, lighten up. I'm sure there's not one among you who hasn't made a really dumb blunder at least a few times.

After this bludgeoning, I hope he hasn't lost his enthusiasm, his curiosity or his motivation!

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#71
In reply to #65

Re: Helium Lifting Power with PSI

02/10/2011 11:10 PM

After this bludgeoning, I hope he hasn't lost his enthusiasm, his curiosity or his motivation!

One can hope, however, that he has lost some of his penchant for being rude. Tornado's first response is right on the money, and if this student "knows all about buoyancy" as he claims, then Tornado's response was enough that the student should have said to himself: "Oh, yeah. Of course." To Tornado he should have said: "Hey thanks, you cleared up my confusion." Instead he replied:

"This in no way answers my question... at all...

That's not even a helpful fact, and is common sense anyway."

Many of us, upon making dumb blunders, display a little humility, and say thanks to those who show us the light. Arrogance is no more charming in a high school student than it is in a middle school student.

My hope would be that he has has gained enough enthusiasm to research his projects, enough curiosity to wonder about how stuff works, and enough motivation to actually find out.

I'd also hope that he realizes that his characterization of the first nine posters as "asses" is rude: "finally something helpful and someone not being a complete ass about my lack of knowledge on this subject."

It is never too early to stifle rudeness. We shouldn't accept this sort of behaviour from an elementary student.

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Anonymous Poster
#67

Re: Helium Lifting Power with PSI

02/10/2011 6:20 PM

This is just like a thermodynamic problem,

you can achieve this floating stuff of the egg of yours at liquid phase of helium at conditions 1-1.5 Kelvin at 25 bars, neglecting the impact. you might as well replace the egg with some other material, because probably your egg will crack at pressure 25 bars.

Ronie

Philippines

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#68

Re: Helium Lifting Power with PSI

02/10/2011 9:56 PM

If we can't pump enough lightness into the box, maybe we can subtract some of the lightness in the room. If pumping helium into the box increases its lightness, then we should pull air out of the room to decrease it's lightness.

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#69
In reply to #68

Re: Helium Lifting Power with PSI

02/10/2011 10:10 PM

On the contrary: the denser the air in the room, the greater the buoyancy of the box/egg combo. About 6 bar would do it (similarly boosting the helium pressure to keep the box from collapsing).

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#70
In reply to #68

Re: Helium Lifting Power with PSI

02/10/2011 10:47 PM

Is there any rule against simply flooding the room with water? Flood the room, place box on water, slowly drain the room. Simple.

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