There is no atmospheric pressure on the moon. All rights reserved. Class-8 » Science. Share with your friends. Khushi answered this. View Full Answer. Aadhya Gupta answered this. Connect and share knowledge within a single location that is structured and easy to search.
So the moons' air pressure would also be very equally small. I suppose that somenone's power to suck an almost 'vacuum' to create an underpressure in the straw is not possible.
Perhaps to increase the surface of your glass could help a bit. I think that gravity doesn't have to do with it a lot because that is the same for the liquid in the straw and outside on the surface of the glass. Perhaps I forgot something Because of big variations of temperature on the moon I suppose the liquid is not frozen nor evaporated.
And probably you should protect yourself and provide yourself with oxygen etc, but they are left out for simplicity of the problem. While the moon does technically have an atmosphere it is for all practical purposes a hard vacuum see the second sentence of the Wikipedia reference. Any liquid in a vacuum will simultaneously boil and freeze, spraying out of the cup in the process.
You, standing in the same vacuum, will quickly expel the contents of your lungs and will no longer be able to suck on a straw. As you will lose consciousness almost immediately the cup and straw will fall from your hand and land beside your body.
If the straw is on your mouth the air in your lungs will do the same thing - your lungs are not strong enough to resist the pressure difference. If we rewrite the question to read "Can you drink a glass of lemonade in lunar gravity with a straw", meaning you do this inside your lunar lander, then the answer becomes "yes, no problem".
We breathe and by extension suck by changing the volume of our lungs and allowing the pressure difference generated by that action to move air into or out of our lungs. Boyle's law: "For a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional. As we contract our diaphragm and raise our rib cage, the volume of our lungs increases and the pressure inside our lungs decreases. Note that breathing in is an active process.
The biggest problem with sucking on the moon is that there isn't any atmospheric pressure to move air or whatever you're sucking into your lungs and thereby equalize the pressure difference. Another way of saying this is that there is no way that you can create a lower pressure within your lungs than there is on the moon. So air will always want to flow out of your lungs. So you are correct in assuming that the lack of atmospheric pressure on the moon would prevent you from sucking. An example of this is if you stick your head outside of a car that is moving very fast.
The air that is moving past you is at a relatively low pressure. I think the answer is a straight-forward No. You could not "suck" the lemonade up the straw. You would have to generate a pressure lower than that of the Moon's atmosphere, which you point out is many orders of magnitude lower than on Earth.
You do this by expanding your mouth or lungs. This also allows air to enter, preventing the straw from working properly. When you drink from a straw, you create a little space of low pressure inside your mouth and in the top of the straw. Then the air outside the straw pushes down on the surface of the drink and forces the liquid up through the straw and into your mouth. Sealing the top of a straw with your finger stops air entering and exerting a downward force on the liquid, leaving only the upwards force of air pressure from below.
This upwards force is stronger than the force of gravity pulling down on the liquid. Tear the wrapping off half of the straw, so that one end is exposed. Put the exposed end in your mouth, take aim, and blow! The wrapper shoots off the other end, like a dart from a blowgun. This is because the atmosphere exerted a pressure upwards from the bottom to prevent the water from falling the headspace above the water has some small downwards pressure that is minimized by the incompressibility of water.
The fluid outside the straw is comparatively at high pressure atmospheric pressure and thus it starts pushing the fluid inside the straw upwards. This is due to what is called the capillary action. It is caused by the surface tension of the liquid and the adhesive force between the liquid and the container which act to lift the liquid up, against the force of gravity. Thus, the weight of the water causes a lower pressure at the top of the straw.
The differential pressure between the air trapped at the top of the straw and the atmospheric pressure outside and at the bottom of the straw then keeps the water in place. The atmosphere pushes the liquid in the glass up into the straw. Since the atmosphere is also pushing down on the liquid in the straw, the liquid rises, just until the force of the atmosphere on the liquid inside the straw exactly balances the force of the atmosphere inside the glass.
Yes there is a limit.
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