At the same atmospheric pressure as Earth, would helium have more lift on the Moon?
108625
I guess the helium ballon will lift the same mass, not more. \nThis is because although the mass will weight less (1/6), also the ballon will have less lift force because this depends on the volume x density x g(moon), and g(moon) is 1/6 also, so the less weight counteracts with less lift force.
856254
The attractive force of the "magnet earth" is much smaller than it's gravitational force. In fact it's negligibly small. Proof: put an iron object on the table, like a knife. Despite it being much more closer to the earth than the moon, it will not budge.
182931
Lift under a liquid (or BOUYANCY FORCE) is defined as the weight of the volume of liquid displaced.  In other words, say a ball displaces 1 cubic meter of water.  The ball will be pushed back up with the same amount of force as the weight of that 1 cubic meter of water.\n\nSince water's density is 999 kg/cubic meter, we're looking at 999 kg of water (water is really heavy!).\n\nNow if we want the force of that water, we'd simply multiply it by the gravitational acceleration, 9.8 m/s/s:\n\n999 * 9.8m/s/s = 9790 Newtons (1 Newton = 1 (kg * m)/(s^2))\n\nSo the ball would be pushed back up with a force of 9790 Newtons.\n\nNow, the hard shell ball will (theoretically) not deform when subjected to the pressure of 10 feet of water.  So the *bouyance force* placed on the hard shell ball is easy to calculate, given the formula above.\n\nThe latex balloon, however, will shrink as it is exposed to increasing pressure, so the volume of water it displaces will be smaller. (I will not solve that problem here as it takes up quite a bit of space to show how much a balloon shrinks as it is subjected to increasing pressure.  Essentially it comes down to writing a spherical force balance and integrating over volume)\n\nConsequently, the bouyancy force exerted on the latex balloon will be smaller, and the ping pong ball would be forced back up through the water harder (and faster) than the balloon.\n\nAs an extreme, ever wondered what happens to helium filled balloons when they are released into the air and they float up until you can't see them anymore?  Since the atmospheric pressure is lower and lower the higher you go, the balloon expands until eventually it pops.  At that point, the popped balloon either falls back to earth or gets swept up into atmospheric currents, which can take it basically anywhere on earth.
135962
Actually, the moon does have an atmosphere, and EXTEAMLY thin, tiny, very small, negligible atmosphere.\n\nThe chances of getting hit are miniscule, there is virtually no risk.  You can see the moon of covered with impact craters, but remember, these happened over the course of billions of years.  The chances are very slim, you would have to VERY unlucky to be hit.
747984
NO, All helium produced is done so through seperating it from air where it occurs naturally, but in very small concentrations. Air is seperated through cryogenic distallation. Unless you have some extraordinary equipment in your house, you will not be able to perform this kind of operation.
719389
since the all of the valance orbitals are filled, helium is much more stable than hydrogen. therefore, i wont explode or catch on fire or anything dangerous
804421
The higher the balloon goes in the atmosphere the less pressure on the balloon. This causes the helium to expand its volume. If the balloon was filled to capacity it would *pop* at higher altitudes.
392567
the answer is a, mercury is much heavier than water and would require a heavier pressure tto reach the same altitude...i think..lol
958106
Since the Moon's gravity is only one sixth that of the Earth, much less fuel is needed to launch from the Moon than from the Earth, assuming the mass launched from each is the same.\nOf course the Moon would not be visible.  It does not make its own light, because its just a big rocky ball.
339606
no. mercury is too small to have a powerfull enough pull to hold an atmosphere
709750
Big rocket on moon: Lots of reaction mass available, low escape velocity, no atmosphere to block the exhaust, and no greenies to complain about the noise and pollution. The moon is gravitationally bound to the earth, so if the moon is moved slowly and carefully enough, the earth will follow. Of course, we'll want to clean up the asteroid belt between Jupiter and Mars first. Great plan for solar main sequence survival.\n\nIn response to "addtional detail". For every action, there is an equal and opposite reaction. That means the gravitational force on the moon due to earth's gravity is exactly the same as the force on the earth due to the moon, but in the opposite direction. Now, since the earth is more massive, that means its acceleration is proportionatly smaller. Since the moon's orbit is circular (at present), that means the acceleration is centripetal and the earth's center orbits in circle of small radius. \n\nThe extreme limit of how hard you can pull on the earth with a rocket on the moon would be if you brought the moon to a stop relative to the earth. The moon will then start falling toward the earth, and the earth toward the moon (though more slowly). However, if you oppose the gravitational force on the moon with rocket thrust of equal an opposite magnitude, plus a bit more to match the acceleration of the earth in both sign and direction, the earth-moon distance with stay the same, and the pair will accelerate together. Note that the rocket exhaust is now pointed towards the earth; this can be avoided by vectoring it off to the side slightly. This added acceleration can be used to accelerate earth in the direction of its motion around the sun. This would cause the earth's orbit to slowly spiral outward. As I said, this is the extreme limit of how hard you can pull (unless you bring the moon closer). In practicle, one need only perturb the moon's orbit to get an effect; it'll just take longer.\n\nYes, one would need a phenomenal energy source to accelerate lunar material for rocket exhaust. Thermonuclear fusion would be the best bet for this. That only requires extacting the naturally occuring deuterium from water. I haven't done the math, but all the earth's ocean's might suffice; deuterium is less than 1% of the hydrogen in water, so we'd hardly miss it. There's lots of water in the outer solar system too, if needed.
706335
The density of helium is only one-seventh of the density of air at the same pressure, so when the balloon is stable, the other six-sevenths has to be accounted for by a combination of (i) the weight of the balloon fabric, and (ii) the tension in the balloon fabric keeping the helium at a higher pressure than the surrounding air.  There is no simple answer, but four miles would not surprise me.
243047
If you wanted to have the effect of being on the mooon (with 1/6 gravity), you would need enoug Helium to balance out 5/6 of your weight.\n\nA 200 pound man has a mass of 90.9 kiligrams.  It takes about .7 kg of Helium to lift 1 kg.  So to cancel out 5/6 of the force of gravity acting on you, you would need about 53 kg of Helium.\nOne mole of Helium has a mass of 4.00 grams.  1 mole of Helium at STP has a volume of about 22.4 Liters.  Thus, you would need about 296800 Liters (946.4 cubic feet) of Helium, this is quite a lot.
859887
Not sure if I understand. You're going to replace the old hydrogen with some new hydrogen that's less dense? The only way for the density of hydrogen to be less is if the pressure is lower or the temperature is higher. Since this is a balloon, the pressure has to match the pressure of the atmosphere. \n\nSo I'll assume the new hydrogen is at a higher temperature. In that case, the balloon can be kept inflated to the same size with fewer molecules. Therefore the mass of the hydrogen will be less because there is less of it. So the bouyancy will increase. The balloon as a whole is less dense so it is more bouyant.
976120
Helium molecules are very small and slowly leak through the balloon wall.\n\nAir contains a mixture of gaseous molecules, primarily Nitrogen and Oxygen.  These are much larger than Helium.
206878
It is possible for the earth to hold an atmosphere due to its gravitational field.  All objects (of any size) are attracted to other objects (of any size) this is called gravity.  The earth's gravitational field therefore holds the oxygen, nitrogen, etc. inside its gravitational field because due to its size its gravity pulls the oxygen molecules to it.  This is also reason why there is more oxygen air etc.  at sea level than in the mountains.  As you ascend higher the gravity is less than at sea level so less air is held by gravity.
1031159
They are called moonquakes.  If the moon had an atmosphere it probably would not be able to keep it or hold it at the moon's surface due to little gravity.  (only 1/6 of earth's)