Make a list of objects or creatures that can fly?
What are some questions you have about flight? Who.... What..... When..... Where..... Why???????? How insects and birds fly? How do heavy airplanes full of people get into the air? What is a force? check glossary Is gravity a force?
What is air? Is it empty space? Can you see it ? How do you know it's really there? What is air made of? Match the name of the gas to its model. Oxygen Carbon Dioxide Nitrogen O O C O O N N Remove to find out Remove to find out Remove to find out
Air is a mixture of gases that surround the Earth. Refusing Funnel Demonstration Ruler demonstration If air takes up space, what do you think will happen? What if it doesn't take up space? 55 gallon drum. The drum is sealed ( no air can get in or escape). If we remove the air from inside the drum, what do you think will happen? Does air take up space? Does air exert pressure?
We use arrows to show the direction of forces. Draw arrows to show the direction of the force applied to the ruler. Make a hypothesis. A hypothesis is an educated guess based on what you already know. If I place the sheet of paper on the ruler then ..... Question: Does air exert pressure? Does it push down on things? Design an investigation.....page 6 text Collect materials you will need to do the investigation. Conduct investigation and record results. Draw conclusions. Make inferences based on your evidence or your results. Table paper Communicate .... share your results and conclusions with the world. Table
Notes.... A force is a push or a pull that makes an object move or change direction if it is already moving. One property of air is that it exerts pressure. Gravity is a pulling force, it pulls all objects toward it. You always have gravity pulling you toward the center of the Earth. Why doesn't it pull you all the way there? The answer is quite simple. Gravity Force exerted by ground. When you are standing on the ground, gravity is pulling you but the ground is also pushing back with an equal force. We call this balanced force s because they are equal forces. When forces are unbalanced , the stronger force always tries to balance with the weaker force. Air always flows from HIGH PRESSURE to LOW PRESSURE .
Even though you cannot see air, it takes up space and can exert pressure on objects. Usually something that takes up space also has mass. Mass is the measure of how much matter the object has. Mass and weight are not the same thing. Weight is a measure of how strong gravity pulls an object toward itself. The mass of the air surrounding Earth is 5 200 000 000 000 000 tonnes . The mass of the air pushing down on the Earth produces air pressure. The air pressing on your shoulders right now is 0.9 tonnes or 900 kg or 1900 pounds. Why do you not feel the 900 kg of air pushing down on your shoulders? Write an explanation in your notebook. Does air have mass?
What happens when air is heated? Review properties of air: It takes up space. It exerts pressure. It has mass. Exploration: Investigate the power hot air exerts. Answer in your notebook after observing the demonstration. 1) What happens as the bag fills with hot air? 2) What happens as the bag cools down?
Density is the measure of matter in a space. It is calculated by dividing the mass by the volume (space). The more molecules(matter) in a space makes it more dense. The less molecules(matter) in a space makes it less dense. A fluid (liquid or gas) that is less dense than the fluid it is placed in will rise. container A container B GAS MOLECULES Which container has the lower density of gas molecules? Which container would have a higher pressure than the other?
Flying Forces 1. What is drag? 2. What is thrust? 3. To move forward, the thrust must be ____________than the drag. 4. What force is needed in order to leave the ground? 5. The front edge of a wing on a plane is a little _________________ than the back edge. 6. Lift must be _______than gravity to stay in the air. 7. What is the wing shape called?
Gas molecules are always in motion, but when they are heated (energy is added) they move faster and spread out from each other. The heated air becomes less dense and rises into the air. Warm air that is less dense has a HIGH PRESSURE compared to cooler air that is more dense. Warm air inside the balloon is less dense and will rise into the cooler air. This is how a hot air balloon overcomes the force of gravity. How can a hot air ballon rise into the air? http://videos.howstuffworks.com/hot-air-balloon-video.htm
Lesson 4 How do objects Move in Fluids? A fluid is any substance that flows. Gases such as air are classified as fluids. You can study how an object moves in air by using water in place of air. It is more convienent to observe objects moving through water than in air. Why??? Will a boat with a square front more through water more quickly than one with a V-shaped front? You can observe the movement of the water much easier. Different shaped objects moving through water? Making a hypothesis. Remove to see one reason
When you try to move through a fluid, the fluid resists and pushes back on the object that is trying to move through it. When you try to run through water, the water pushes back on you and slows you down. This is called DRAG. Isaac Newton Laws of Motion " Every action has an equal and opposite reaction" All fluids exert this type of resistance, including air. The shape and size of the object moving through the fluid affects the resistance. Example: Hand out the window of the car.
Resistance force always acts perpendicular to the surface it is pushing on. Which shape of boat would have the most resistance when moving in a fluid?
All of these object move through a fluid. What characteristics do the "fronts" of the objects share? Why are they designed this way?
Lesson 5: How can Objects Overcome Gravity? Gravity is a strong force that pulls everything down toward the center of the Earth. It can be overcome by an upward force called LIFT. Lift occurs when there is a high pressures produced on the bottom surface of an object compared to the top surface. Gravity Lift If a helicopter is hovering above the ground at the same height, what is the relationship between the forces of gravity and lift? The force of gravity must be equal to the force of lift. Balanced forces. Remove to see the answer
BERNOULLI'S PRINCIPLE In 1738, Daniel Bernoulli discovered the relationship between the speed of a moving fluid and the pressure it creates. If the speed of the fluid increases he found that the pressure it exerts is decreased. Fast moving fluids exert less pressure than slow moving fluids. How does this explain the paper lifting up when you blow across the surface of it? Read about curveballs Page 19
How can Heavy Objects Fly? A heavy object must create enough lift to overcome the force of gravity acting on it. Lesson 6
Facts about Lift: Lift depends on shape- an airfoil shape creates more lift than a flat shape Lift depends on the angle of attack Lift depends on speed- lift increases as speed increases Lift depends on direction- lift acts perpendicular to the direction of the object's movement
Drag is the aerodynamic force that acts against an object moving through a fliuid. It's what pushes on anything moving through air or water. Flying objects must overcome drag in order to fly. What objects can you think of that use drag for advantage? Parachutes Drag depends on the shape - a shape with low drag usually is long, thin , smooth and rounded at the front and tapering at the back. Drag depends on speed- drag tends to increase as speed increases. Drag depends on direction- drag acts in the opposite direction to the object's movement.
Which plane would experience a greater drag force? FLOATS Why? A modern airplane has landing gear that can be stowed after take-off. Why would they want to put the landing gear away after take-off?
PROJECT DRAG You have just received an e-mail from a friend telling you about a great opportunity to make some cash. You find out that companies offer money if people solve problems for them. An engineering firm wants you to design a device that allows boxes of food to be dropped from a helicopter safely. The food will be used by people in need. It is too dangerous for the helicopters to land because the country is at war. It is important that the food lands softly on the ground because some of it is breakable. You decide to take the challenge but first you will make a model of the device. You decide to use a base ten block to model the box of food. You can use any other materials in the classroom to create your device. Next class is simulation time. Your challenge is for your model to take the least amount of time to drop to the floor. http://videos.howstuffworks.com/skydiving-video.htm
Review Activity : 1) Draw a diagram of an airfoil. Show the low pressure area, high pressure area, faster moving air, slower moving air. 2) What is the name of the person who showed that faster moving fluids exert less pressure? 3) Label the 4 forces acting on a flying object.
Label the forces acting on the airplane. What other force must be acting in order to have this plane fly?
Thrust How Are Flying Objects Propelled? What is necessary to move an object forward in the air? Thrust is what propels a flying object through the air. Jet Engines: air enters the engine and is compressed, fuel is added and ignited. The hot gases expand and push hard against the front of the engine and bounce back shooting through the rear exhaust and pushing the plane forward. Rockets: works on the same principles as the jet engine except they carry their own oxygen and they use different fuels. Propellers: a engine turns the propellers. Propellers have an airfoil shape that pushes the air back. The backward flow of air thrusts the aircraft forward. A propeller is a special spinning wing that is pointed in a direction that causes lift to become thrust. p.25/27
Helicopters wings are shaped like airfoils also. The helicopter's motor turns the drive shaft which turns the main rotor. As the blades turn they create lift. The main rotor engine would turn the entire helicopter spinning in circles without the tail rotor to stabilize it. Main rotor Tail rotor side to side movement controlled p.29
What happens when an Aircraft has no engine? Read page 30/31
Engineered Streamlining p.33 What tool is used to study and test flight under controlled conditions? WIND TUNNEL Move box to reveal the answer
How does a Pilot Control Flight? Steering a plane Control Surfaces
How does each flight control device affect the movement of the airplane during flight? http://travel.howstuffworks.com/airplane20.htm Elevators up Elevators down Flaps down Flaps up Rudder left Rudder right Left ailerons Up / Right ailerons Down Left ailerons Down / Right ailerons Up
How does Nature Use the Four Forces? Compare the parts of an airplane to a bird of flight. How is thrust produced in each? How is lift produced in each? How do each reduce or increase drag? How do each control the position of their nose and tail? How do each turn ( bank left or right) while in flight? How do each control their landing gear? Why does a bird tuck its feet under itself while in flight?
Refusing funnel Hot air Balloon Crushing a bottle or can with air pressure Making a propeller p.26 Making an Airfoil p.20 Making a rotating airfoil p.28 Moving different shaped objects through a fluid Blowing across the top of a piece of Paper Match Rocket Bernoulli's principle: blowing between balloons or tin cans Designing an object to increase its drag p.22 Making a glider p.32 Making a glider with control surfaces p.36 Blow Dryer/Funnel( /Ping Pong Cannon Rubber and Ice Cream Container Flight Activities and Demonstrations:
Scientific Method Template: Question: ??How ? Why? Does.... affect.... ? How will changing ...... affect......? Hypothesis: If ...... then...... Materials: 1) 2) 3) 4) 5) Procedure: First..... Then.... Next.... Results: Table and/or chart and/or graph Conclusions: My hypothesis was ..... Based on the results we think that .........
elastic The number of turns in the elastic will affect what force? a) drag b) gravity c) thrust d) lift
Experimental controls In order for an experiment to be a fair test........ Variables: ALL of the possible things that could affect the outcome of an experiment Watch Brainpop: Scientific Method