How does air lift weight?

[ihelwig]

I have been trying to find out how is it that air can lift things that are heavy, but haven't been able to find anything. CAN YOU HELP?????

[ChrisG]

Are you thinking of heavy objects that float, like hot air balloons, or denser-than-air objects that can be lifted by high velocity winds or airfoils?

For floating objects, try doing an internet search for "buoyancy" or "archimedes principal." Keep in mind that many web sites will discuss these principals for water, but the same principals apply to objects floating in air.

If you are interested in objects lifted by high speed winds, you could try searching for information about tornadoes. If you are interested in planes, birds, etc. try looking for information about airfoils.

Good luck.

[ghariman]

Hi there,

I am just following up on ChrisG's post.

I am also confused about your notion that Air can lift heavy objects. Perhaps you are a bit confused about your question.

Most likely you may be asking how is it that a heavy airplane can lift off from the ground ? The answer is that it uses a concept called "lift" that is created by the airplane's wing. You can check these website's out:
http://en.wikipedia.org/wiki/Lift_%28force%29
http://en.wikipedia.org/wiki/Airfoils
Similar concept is used on non-fixed aircraft such as the helicopter where the rotating blades create lift.

How about balloons you may ask (as well mentioned by ChrisG).
Well they operate on the fact that certain gases can have different density than others and thus will be able to 'float'.
A hot air balloon uses hot air which is lighter than air temperature air.
http://en.wikipedia.org/wiki/Hot_air_balloon
Other balloons operate differently. For example the famous Hindenburg
http://en.wikipedia.org/wiki/LZ_129_Hindenburg
is filled with Helium which is lighter than air.

Hope these links help you more.

[ihelwig]

I want to explain how air lift weight. For example, if I place a funnel on the jar and cover this with molding clay, when I pour water into the funnel won't fall into the jar because it is sealed with the molding clay. If I unseal the molding clay, then the water falls into the jar. Therefore, I believe that the air in the jar was lifting the water in the funnel, , right? if so, i need to explain why/how.

[ChrisG]

Hi,
What is your grade level? This problem can be described in complicated or simple terms, depending on your science background.

Thanks,
Chris

[ghariman]

Hi,

Ah there you go. See you need to post your questions with more detail.

Okay in your description in fact it is not Air that is "lifting" the water.
What happens is when you pour the water into the jar via a funnel that you have sealed to the mouth of the jar with a mold clay, then there is NO way for the air inside the jar to come out of the jar.

Therefore since there is no way for the Air to come out of the jar then the water trying to get into the jar will not be able to displace the air.

In fact you can do the same experiment but backwards. If you have a bottle full of water and you put mold-clay on the top and insert a small drinking straw into it. At first close the straw with your thumb. Then flip the bottle upside down and let the water settle. When you release your thumb from the straw, NONE of the water will flow out of the bottle as there is no way for the air outside the bottle to get into the bottle to displace the water.

Read this that I found on the internet to explain more about "AIR":
http://www.delta-education.com/download ... 8-3056.pdf

I hope this helps.

[ihelwig]

this is for a 5th grade science fair project

[ChrisG]

Thanks for the information. I think the explanation that Ghariman gave should answer your question. If there are parts that you don't understand, or if you want to know more, just let us know.