Do you know what air actually is. NO.... thats what I thought. Get ready to learn all about the stuff around you everywhere you are. First of all its air has many basic properties. It takes up space, has mass thats measurable, it exerts pressure basically everywhere, and it has a temperature. Air is a mixture. It is a mixture between these main chemicals. Nitrogen, oxygen, water vapor, argon, and carbon dioxide. Air pressure is the amount of force exerted onto a surface by the air molecules. As you go up higher in the atmosphere, the air pressure decreases more and more. This occurs because air is matter and gravity forces it to be pushed down. Therefore, there is much more density of air near the bottom of the atmosphere and less and less as you go up the atmosphere. There is more air molecules at the top and less at the bottom.
(Column of air with "visible" air molecules) (Graph of altitude (atmosphere) vs air pressure)
https://www.itslearning.com/main.aspx?CourseID=848 http://www.npl.co.uk/upload/img_400/Altitude_vs_Pressure.gif
Like I said before, air pressure is the amount of force exerted onto a surface by the air molecules. In class we did an experiment of putting water in a cup then putting a card to seal the cup of water and flipped it upside down. We discovered that the water and air inside the cup stayed inside when held upside down. The reason for this was because of air pressure. There was air pushing down from the cup pushing at the water and cup but outside of the card, air pressure was also pushing back at the cup and equaled the same pressure. The air pressure equaled the pressure inside so the card stayed the same and the water inside and air inside could not come out or air get in from outside. When we put a pin at the top of the cup, the water released. This was because the air pressure released at the hole where the pin was and therefore, broke the seal of air pressure collapsing the air pressure outside going at the cup so the water escaped the cup.
Cup with index card. Purple arrow showing air pressure. (blue dots water molecules purple dots air molecules)
Original picture and drawing by Tony Park
In class we did a demo of having an aluminum can of water being heated up. Once hot enough, Mr. Battaglia put it in a pan of cold water and the can seemed to make a whooshing sound and basically collapsing inside itself. The reason for this was because of the magnificent air pressure once again! First, the can has air and water inside of it. These two things are pushing the air pressure on the outside that is forever pushing inwards and outwards at the same force making it stay normal. As the can heated, the air molecules moved faster and expanded out of the can. Water vapor then fills the can as the water evaporated. Once the can with the water vapor hit the water upside down with the opening in the water, the water vapor in the can condensed instantly creating a partial vacuum. The extremely low pressure of the partial vacuum inside the can made it possible for the pressure of the air outside the can everywhere to crush it inside.
Diagram of the four steps showing the can collapsing Original picture and drawing by Tony Park
In class, we did an experiment where we tested trying to drink water with straws in different ways. The first example of was when we one of our classmates drank water from a cup with a straw like a regular person. The sip was like a vacuum where the water is being sucked up. Because of this vacuum, the air pressure above the water in the cup helped push the water down and into the straw. The next trial was when our classmate once again drank water from a cup but with two straws this time. There is basically the same exact result with the two straws. There was still a vacuum being created and the air pressure so she would get the same amount of water. The last experiment, had some real excitement in it. This time, our fellow classmate once again (thanks classmate) “tried” to drink water but with a straw in the cup and a straw outside of the cup. This time however, she could not drink the water. This was because the vacuum that was once created before, was filled with air and could not be a vacuum because the straw outside of the cup took in water and filled the water. As she tried to suck in water, the vacuum kept on being filled with air and all she would suck in was air. The seal that was once there for the vacuum was broken.
First picture was classmate drinking water with regular one straw.
Second picture was classmate “trying” to drink water with a straw in cup and straw out of cup.
Original picture and drawing by Tony Park (sorry for bad drawing)
Air pressure changes in an airplane and this causes our ears to pop when the plane ascends and descends. As you ascend in an airplane and the air pressure decreases at fast rates, the air trapped in your inner ear will cause your eardrums to push outward. This pushing of eardrum causes you discomfort and also causes the “pop” in your ears. As you go down in an airplane and descend, our ears also pop once again. This time, the exact opposite thing happens and the eardrum is pushed inwards. This is because the air pressure increases at a very fast rate but your ears are still adjusted to the lower air pressure.
This diagram shows what happens to one's ear as the air pressure changes as you go up or down an airplane
http://www.merckmanuals.com/media/home/figures/ENT_eustachian_tube.gif
In class, we did an experiment where we tested trying to drink water with straws in different ways. The first example of was when we one of our classmates drank water from a cup with a straw like a regular person. The sip was like a vacuum where the water is being sucked up. Because of this vacuum, the air pressure above the water in the cup helped push the water down and into the straw. The next trial was when our classmate once again drank water from a cup but with two straws this time. There is basically the same exact result with the two straws. There was still a vacuum being created and the air pressure so she would get the same amount of water. The last experiment, had some real excitement in it. This time, our fellow classmate once again (thanks classmate) “tried” to drink water but with a straw in the cup and a straw outside of the cup. This time however, she could not drink the water. This was because the vacuum that was once created before, was filled with air and could not be a vacuum because the straw outside of the cup took in water and filled the water. As she tried to suck in water, the vacuum kept on being filled with air and all she would suck in was air. The seal that was once there for the vacuum was broken.
First picture was classmate drinking water with regular one straw.
Second picture was classmate “trying” to drink water with a straw in cup and straw out of cup.
Original picture and drawing by Tony Park (sorry for bad drawing)
Air pressure changes in an airplane and this causes our ears to pop when the plane ascends and descends. As you ascend in an airplane and the air pressure decreases at fast rates, the air trapped in your inner ear will cause your eardrums to push outward. This pushing of eardrum causes you discomfort and also causes the “pop” in your ears. As you go down in an airplane and descend, our ears also pop once again. This time, the exact opposite thing happens and the eardrum is pushed inwards. This is because the air pressure increases at a very fast rate but your ears are still adjusted to the lower air pressure.
This diagram shows what happens to one's ear as the air pressure changes as you go up or down an airplane
http://www.merckmanuals.com/media/home/figures/ENT_eustachian_tube.gif
Here is a really swell video showing an explanation of why our ears pop as we fly
http://www.youtube.com/watch?v=SWg4qKzrUoo
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