The Ups and Downs of Air Pressure!

       In third grade science class we have embarked on the journey of studying zoology. We have been discussing how scientists classify animals, and came up with our very own mnemonic phrase to help us remember the system of classification. We then learned a few things about flight and how God gifted some animals with the amazing ability to fly. The students learned that air pressure is a key component of a bird's ability to fly. To demonstrate this principle and to allow the students to experience how air pressure works, we conducted an experiment! Read below to find out what we did!

Uplifting Pressure!

Materials Used:

• A cup completely full of water
• One straw cut in half (first half must stick out of the water by only 1/2 an inch)
• trash bag 

Procedure:

• Place the trash bag over the table and put the cup on top. 
• Put the longer straw in the cup of water.
• Move the cup to the edge of the desk.
• Squat down so your eyes are level with the cup.
• Using your fingers to hold the small straw next to the edge of the cup, blow through the other straw at an angle towards the top of the straw in the cup. (Angle the straw upwards so that the air coming out of it passes right over the top of the straw in the cup.)
• Keep blowing and blowing over the top of the straw in the cup. 

Recorded Class Hypothesis:

• "The water will begin to bubble and will eventually spill out of the cup."
• "Nothing will happen to the water."
• "The air will make a whirling sound, but no water will come out of the cup." 

Results:

• A stream of water squirted out of the straw that was in the cup. 

Conclusion:

• When the students blew air over the top of the straw, the moving air could not press down as hard on the water in the straw. The air over the rest of the water in the cup was not moving, so it continued to press down on the water with its full pressure.
• Since the water in the cup was being pressed down harder than the water in the straw, water was forced up and out of the straw! 
• This is a lot like what happens to a bird's wing. 
• Just as the difference in air pressure over the straw and the rest of the cup lifted water out of the straw, the difference in air pressure between the top and bottom of a bird's wing lifts the wing into the air!