Flight Unit

1. Flight Unit Miss Anders

2. What is air? • the invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen. • Why do we have to know about air when studying flight?

3. What are the properties of air? The most basic properties of air are: • It takes up space (it will fill up whatever container it is in) • It has a measurable mass (it can be weighed: it has weight) • It exerts pressure (it can move things: think of wind) • Air has temperature (hot and cold fronts) • Air will expand when heated

4. Putting that into Context • The world we live in is covered with air, called the atmosphere. Although we can't see it, the air in our atmosphere is made up of a mixture of colorless gases. Earth's gravity pulls the air to the planet's surface. This is why the air in the atmosphere is densest near the ground (where the pull of gravity is greatest). The higher you go, the thinner the air becomes. Air pushes on all surfaces that it touches.

7. Questions • Is air “oxygen”? • If we were to weigh a deflated balloon and then blow it up with air and weigh it again would the weight change?

8. Did you know?

9. 4 Forces of Flight

10. Weight or Gravity • Gravity is the force that makes objects fall toward the earth. • It is because of gravity that objects feel heavy. • For an object to fly, an upward force must act on it to overcome the downward pull of gravity.

11. Lift • Opposite to gravity, lift is the force that acts upward against gravity and makes it possible for a heavier than air aircraft to rise in the air. • Most of lift on a normal airliner is generated by the wings • Lift is produced by the motion of the airplane through the air.

12. Links to the Bernoulli Effect • As the aircraft moves forward into air, the wing deflects the air. Some of the air moves to flow above the wing while some of the air moves to flow below the wing. • The wing is curved to help the air that flows above the wing move more quickly than the air that was able to flow below the non-curved bottom of the wing.

13. The wind is broken up by the wing:

14. Bernoulli’s principle in picture:

15. Bernoulli’s principle in words: • Key ideas: • The shape of an aircraft’s wings is critical to its ability to fly • As birds’ wings are curved on top, the wing of an airplane had to be curve on top as well- this shape (curved on top, flat underneath) is called an airfoil • The distance across the top of an airfoil has to be longer than its underside

16. Bernoulli’s principle in words: • When the wing is travelling fast enough through the air, the air moving over the wing is travelling much faster than the air travelling under the wing. • The faster the air travels the less pressure it exerts on the wing • Since the air travelling under the wing is moving slower, it exerts more pressure • This difference is called LIFT

17. Bernoulli’s Principle

18. Flying and Animals • Lenoardo Da Vinci (1452-1519), Italy This famous inventor drew human powered flying machiens called ornithopters which had wings that flapped like those of a bird Science Text book page 214

20. What does the Bernoulli principle look like on a bird?

22. Forces of flight in action

23. Birds in comparison to man-made aircrafts

24. Can penguins fly? • Penguins cannot fly because they are such good swimmers - and no bird can excel at both, said scientists. • They started to fly through the ocean instead of the air as they developed wing-propelled diving skills that allowed them to forage for food at increasing depths.

25. The other two forces of flight • Thrust: the forward force produced by the aircrafts engine • Drag: the air resistance the aircraft encounters • These two forces are opposing forces and push the aircraft in opposite directions (that’s why they are on opposite sides of each other on an aircraft or bird!)

26. Thrust • There are various ways an aircraft can gain thrust. • Propeller: this is a rotating set of blades driven by an engine which pulls the airplane forward through air (the blades are shaped like an airfoil) The engine turns the propeller. The propeller is specially shaped to push the air backwards which results in a force that moves the aircraft forward

27. Thrust Connection • Swimmers move forward through water in a similar way, by pushing water backward

28. Thrust continued… • The force moving the aircraft forwards is called the thrust. • A jet aircraft can go faster than a propeller aircraft. Where does its thrust come from?

29. Thrust continued… • A jet engine burns fuel, like a piston engine. Hot exhaust gases are forced backwards at great speed. • Pushing gases backwards makes the plane go forwards.

30. Drag • This is the force that works against thrust. • The drag of the air makes it hard for the plane to move quickly. Another name for drag is air resistance. • What's a good shape for getting through the air?  *A streamlined shape slips smoothly through the air. A wind tunnel can be used to show how the air moves. 

31. Who needs a lot of drag? • Drag can be a useful force for slowing things down. A big area gives more drag. 

32. Drag connection: Have you ever felt the force of drag? • You don't notice the air's drag when you walk or run. But you feel the force of drag when you try to move through water. Fish and dolphins must have a streamlined shape to reduce their drag.  (There's more drag in water than in air, because it is denser). 

33. How is drag useful? • Sometimes drag can be useful in flight. • For example, when an aircraft lands it puts up the flaps on its wings to create drag to slow the aircraft down and eventually bring it to a stop

34. Effects of aviation on society and the environment • What is a carbon footprint? the amount of carbon dioxide and other carbon compounds emitted due to the consumption of fossil fuels by a particular person, group, etc. What do we know about these effects?

35. Is flying always worse than other forms of transport? • Yes, just about. The carbon footprint of any form of transport depends on a combination of factors, such as the type of engine, the number of passengers, the length of the journey, the speed and the type of fuel or power. • Does flying deserve to be labelled the big polluter? • The problem with flying is that it often involves travelling huge distances in such a small amount of time, so it is easy to notch up a huge carbon bill from a single journey. Also, CO2 emitted at high altitude has a greater affect on climate change than the same amount at ground level.

36. If we stop flying, will the economies of developing countries suffer? • Many of the world’s poorest countries rely on tourism and have few other economic alternatives. Tourism is now the principal export earner for a third of developing nations. In developed countries, too, tourism is valuable for conservation and rural development. If you consider how best to use your flight, and choose to go on trips that bring tangible benefits to the destination – wherever it is in the world – you can make a significant difference to conservation and to local communities.

37. Sample issues: • Crop dusting from planes allows the chemicals to spread quickly over large crop areas which is critical to pest control and crop protection • But… the planes cannot direct the chemicals onto the target crop with precision which means the chemicals spread where they are not wanted

38. Another issue: • The speed and ease of air travel allow quick transportation of organs for lifesaving transplants, quick transportation of injured patients to hospitals, and trips for business and pleasure • Air travel also increases the risk of spreading infectious diseases and creates noise and air pollution

39. Group Consolidation: • You will be put into 5 groups that represent 5 different perspectives of groups of people that are affected by the flight industry. You must prove why or why not flight should be an industry that continues to grow or gets shut down. • 5 PERSPECTIVES are: • Farmers • Doctors • Airline workers • Home owners (people who travel) • Tour operators (Air Canada, etc)