1. Air is like a fluid and it takes up space. 2. Air has weight. 3. Air exerts pressure. 4. The Earth’s atmosphere is made up of many different gases. 5. Air can be compressed. Air Takes up Space (Experiments) #1 Capture air inside of a bag. #2 The water stayed in the funnel because the air takes up the space inside the bottle. #3 The tissue didn’t get wet because the air takes up the space inside the cup. http://www.youtube.com/watch?v=66oOUhlX3J4 #4 The balloon could not be blown up because the air inside the bottle is already taking up the space. Air Has Weight (Experiments) #1 By putting the newspaper on top of the meter stick it increased the surface area for air to sit on therefore increasing the weight. http://www.youtube.com/watch?v=zbNkoR3rOeI #2 When one of the balloons popped the other dropped because of the weight of the air inside the balloon. http://www.youtube.com/watch?v=CTSO17Z6jeE&feature=related Air Exerts Pressure (Experiments) #1 The air pressure pushing upward on the index card is greater than the force of gravity pulling the water down. #2 Another reason why the tissue didn’t get wet is because the air inside the glass was exerting pressure against the water not allowing it to enter. #3 A)When the balloon is filled up it is exerting pressure on the walls of the balloon. B) When the balloon was let go the pressure inside the balloon propelled the balloon forward (Newton’s 3rd Law) a. b. A change in temperature will change air pressure. Atmospheric (air) pressure – is measured with a barometer. Film Canister Rockets C. The more tiny air particles there are above a place or object the higher the air pressure. (Stack of Books Analogy) 1. Measures atmospheric pressure 2. Indicates the height of a place above sea- level 3. Used for weather prediction, as high air pressure in a region indicates fair weather while low pressure indicates that storms are more likely. Air is a fluid and is capable of being compressed! Why can it be compressed? Where do we see or use compressed air?? Balloons Basketballs / Footballs / Soccer Balls Bike and Automobile Tires 1. The more oxygen a fire gets the more it burns. 2. If you stoke a fire with a stick or blow on the hot coals or burning wood it will burn more. This is because you have let more oxygen into the fire. 1. Water vapor is also an ingredient of air. 2. Damp air will effect metals. – it will change their colour (brown) and they start to rust. 3. Rust will form CORROSION and overtime the rust will destroy the metal 4. We have a lot of rust in Canada because of our damp climate 1. In all animals, gaseous exchange takes place through lungs or gills. 2. Oxygen is taken in and carbon dioxide is given off. 1. The particles in air are always moving. 2. Air like a fluid will always move from a high pressure area to a low pressure area 3. Bernoulli’s Principle • Daniel Bernoulli – Swiss scientist and mathematician • He studied how water and air flow. • He found that FAST MOVING AIR HAS LOWER PRESSURE AND SLOW MOVING AIR HAS HIGHER PRESSURE. • It was through this principle that we understand why birds and airplanes can fly. • When air rushes past the wing of a plane, it flows above and below the wing. • The top part of the wing is rounded and the bottom is fairly straight. • Therefore, air rushing over the top of the wing has to travel a greater distance to the back of the wing compared to the bottom. • As a result, the air on the top of the wing has to travel faster to keep up with the air underneath. • This creates a low pressure area on the top of the wing.and high pressure area on the bottom. • The difference of pressures on the surfaces of the wing create LIFT (the upward force that keeps planes and birds aloft.) What are some of the similarities in design between the airplane compared to birds? Streamline / Aerodynamic design Wings / Wings or Airfoil Landing gear / Legs Tail / Rear wing (stabilizer) Any others? Cool Characteristics of birds: Two important things that birds have that help them keep their weight low are: 1) Feathers – are light, flexible, used for protection and also to keep the bird warm. 2) Hollow bones – are very light Forces on an Airplane Forces that act on birds during flight: 1) Lift – the force that pushes upward, created by the movement of air over and under the wings. 2) Drag – the force of the air pressing against the bird and slowing them down. 3) Weight (gravity) – the force that pulls the bird down. 4) Thrust – the force that moves the bird forward, caused when a bird flaps its wings. What is Propulsion? It means to push forward or drive an object forward. A propulsion system is a machine that produces thrust. Now lets take a look at how airplanes and animals fly…or propel themselves. • Thrust – a force which can cause an object to move in a direction. (Eg. Balloon Rocket) - Thrust often comes from muscles or engines. • Newton’s Third Law – For every action (in this case, air escaping the balloon) there is an equal and opposite reaction (the balloon is propelled forward). • Push - the movement an animals wings make. They push against the air. •Propellers – blades which are turned at high speeds - Eg. Helicopters or Airplanes In order for devices or living things to fly: They must have sufficient lift to overcome the downward force of gravity. Parachutes are designed to create _______ DRAG or Air Resistance so that they fall slowly to the earth. The larger the Parachute, the slower it will fall to the earth. Which other force affects the Gravity parachute? _________ Which force is greater? Making an object streamline or aerodynamic: Streamline: a shape designed to have as little air resistance or drag as possible. How can you make an object more streamline? 1) Round edges 2) Slope surfaces 3) Smooth out surfaces 4) What else?? Aircrafts: Race cars: Race Boats: Canadian Geese: Bad examples of Streamlining: Activity: Using only one piece of paper, design an object that is very streamline or aerodynamic.