Air & Aerodynamics Topic A
Lesson #1 • Read through glossary • Mystery Bag activity • Complete worksheet • Read/ Highlight notes: Is air empty space? • Copy the following notes: What is the difference between oxygen and air? Air is a mixture of many types of gases. Oxygen is one of the gases that make up air. The air we breathe is made up of about 78% nitrogen and 20% oxygen. The remaining 2% is made up of argon, carbon dioxide, carbon monoxide and other gases in trace amounts.
Lesson #2 • Discussion questions: • Why was water not able to flow into the jar when the seal was tight? • What is happening when you poke the hole in the plasticine? • Based on these two activities, what do you know about air?
Lesson #3 Huff and Puff As you inflate the balloon, it takes up more space in the bottle. But the bottle is already full of air. Even though you can’t see it, air takes up space. When you try and inflate the balloon, the air trapped inside the bottle prevents you from doing so. When you blow, the balloon will inflate a little as the air trapped inside the bottle is compressed (squeezed into a smaller space). When compressed air begins to push back as hard as you are blowing in (air pressure equals the pressure you are applying), the balloon cannot get any bigger.
Lesson #4 A-Weigh We Go The balance tips because the inflated balloon is heavier than the empty one. Air is quite heavy. The only difference between the empty and the full balloon is that the full balloon has air in it. This proves that air has mass.
Lesson #5 Draw Straws Tube in a cup Air takes up space and air pressure pushes out the water by pushing down on the water in the bowl. The air in the cup can escape through the tube, making room for the water to move up the cup.
Lesson #6- read/ highlight Take the Plunge Pushing the plunger in: The plunger is pushing air from the top of the syringe towards the bottom. This creates a problem of space because you are trying to compress a large volume of air into a much smaller space. The plunger gets more difficult to push as the air gets more compressed and takes up space. Pulling the plunger out: When you try to pull the plunger out, you must overcome the force of the air pushing in on the plunger. As the little bit of air that remains in the syringe expands to fill the increasing space, the pressure in the syringe is very low compared with the air outside the syringe. If you pull the plunger part way out of the larger syringe, when it is let go, the plunger would move part way back is due to the lower pressure inside the syringe (or greater air pressure outside the syringe). You are observing the effects of changing air pressure.
Lesson #7 Hovercraft A hovercraft is a flying machine that is carried on a cushion of air. A powerful engine drives a fan that blows air downwards. A rubber “skirt” that runs round the edge of the hovercraft traps the air, lifting it clear off the ground. Other engines drive propellers that push the hovercraft along. A large hovercraft can support dozens of cars and as many as 400 passengers because the weight is distributed over the whole air cushion. Videos: https://www.youtube.com/watch?v=UOYUeznrXvs&feature=youtu.be https://www.youtube.com/watch?v=0yFMF1sSb2E&feature=youtu.be
Quiz #1 Answer the questions on lined paper. You don’t need to write out the questions. What is the substance all around us? Warm air does what? Cool air does what? True or False 4. Air has weight? 5. A hovercraft cannot support/ lift cars.
Lesson #9 Crushing Air: • What’s happening to the air inside the bottle as the bottle is collapsing? • Low air pressure • What’s happening to the air outside the bottle as the bottle is collapsing? • Is cooler and heavier, high air pressure Raise up your books: • Air exerts pressure • That pressure can be used to do work?
Lesson #10 Air powered rocket: What is powering this rocket? How could we use this air power in everyday life? How could you make the rocket go faster and/or farther? Compressed Air: Compression is the squeezing of the particles of a gas or porous body into a smaller space. Extra air can be squeezed into a container, so the air pressure inside the container becomes greater. Squeezed in air is called compressed air. Compressed air is used in balloons, footballs, basketballs and in bicycle/automobile tires.
Lesson #11 Medicine Dropper Submarine The medicine dropper will float in water, but if the right amount of water is taken up by the dropper, it can be made to sink. By varying the compression of the bottle, the submarine will rise and fall. As the bottle is compressed, the air in the dropper is compressed and more water moves into the dropper. Water has more mass than air and so the dropper sinks. Discussion questions: • Why did the diver go down? • Why did it return to the surface when you let go? • What happens if the jar isn’t full to the brim with water? • What happens as you squeeze the bottle?
What is air pressure? Air pressure is the force that air exerts over a given area. The particles make air move very quickly. The warmer they get, the more quickly they move. The more quickly they move, the more pressure they exert. Air pressure is measured in kilopascals.
Lesson #12 Lift Off: When you blow on the paper, this creates a low pressure area. The paper moves because of higher atmospheric pressure. This is called lift. Lift is also an upward force which acts against the force of gravity. Lift is linked to Bernoulli’s Principle. Bernoulli’s Principle explains that fast moving air creates a low air pressure and that slow moving air creates a high pressure. https://youtu.be/NIHNtjFJook
Lesson #13 Balloon & Hairdryer experiment This activity is an example of Bernoulli’s Principle. • Slow moving air has greater pressure than fast moving air. • The slow moving air surrounding it pushes the balloon back into the stream of air. • If the dryer is raised or lowered the balloon will follow the movement. If the dryer is turned to a higher speed the balloon will “float” higher into the air. • If a fast speed, the balloon will then slip out of the stream of air and no longer be part of the hairdryers air stream.
What is Gravity? • Gravity is a force that exists between any two objects that have mass. Even two objects of relatively low mass, such as two books, create a gravitational force between them. We don’t notice this force because it is very weak. • The force created between Earth and a book, however, is much greater because of the huge mass of Earth. • The gravitational pull between Earth and the moon keeps the moon in orbit around Earth. Because the two objects are far apart, the pull of gravity isn’t strong enough to bring the moon crashing to Earth. The speed of the moon’s orbit also balances the gravitational force between the two. • In order for anything to fly, it must overcome the force of gravity.
Lesson #15 QUIZ #1 Air and Aerodynamics Quiz: What Holds An Airplane Up? Directions: Draw and explain each of the following and how it helps to hold an airplane up. 1. The wing shape 2. The air flow on the wing as the airplane moves 3. The speed of the air moving over the wing 4. The air pressure
Lesson #16 Is there a difference in the rate of falling between light and heavy objects? Conclusion: • They fall at the same rate. The force of gravity is constant; the heavier ball will fall with greater force and would make a deeper impression. • The force of attraction due to gravity is greater, the more massive the object, the greater the lift must be to get the object to fly.
Lesson #19: Thrust, Drag & Lift Lift is greater than Mass (Weight) = plane ascends Thrust greater than Drag = plane faster Lift, mass, thrust, drag equal = plane hovers Thrust less than drag = plane slows down Lift less than Mass (Weight) = plane descends
Lesson #19- Quiz #2 Four Forces of Flight Quiz Directions: Fill in the Blanks (write the number and your answer) 1. If ______ becomes greater than Mass = plane ascends 2. If Thrust becomes greater than Drag = _______ 3. If lift, weight, thrust and drag are equal = _______ 4. If Thrust becomes less than _____ = plane slows down 5. If Lift becomes less than ______ = plane descends
Lesson #24 Discussion Questions: • Paper Drag: • Why did they crumpled paper land on the floor first? • What does this information tell us about flying aircraft and animals? • When is it important to have a large streamlined surface pushing against the air? • When is it important to have a streamlined surface? • Parachute Drag: • Was this a fair test? • Does one have more drag? Which one? • Why did the crumpled parachute land on the floor first?
Lesson #25 Fruity Oxidation: • A natural way to protect fruit from rapid oxidation is to leave the peel on. • Refrigeration will slow down oxidation. • Ascorbic acid in liquids like lemon juice can help, as well as covering fruit (limits air exposure). What’s the best way to prevent fruit from oxidizing if you wanted to make a fruit salad? • Sprinkle it with lemon juice, cover with plastic and put it in the fridge Videos: https://www.youtube.com/watch?v=ZwU8xY5VnQk • https://www.youtube.com/watch?v=qd2B9yCKzc0
Rusting is oxidation: Oxygen in the air reacts with the chemicals on the surface of an object. Oxygen replaces other substances Clue of oxygen= brownish color (like rust on a car)