Printer Friendly

Air power.

The Power of Moving Air

People have long used the power of wind to move sailing ships across the water. Kites and hot-air balloons also need wind to make them move. Today, propellers and jet engines move air rapidly to push airplanes forward. In jet engines, the heat that comes from burning fuel expands the air. The high-speed rush of this hot air powers the plane. The power of moving air to push something forward is called thrust.

The Power of Still Air

Air that is not moving can be powerful, too. Have you ever wondered why a parachute drifts so slowly to Earth? Think about trying to walk quickly through water. It's hard to do, isn't it? The water slows you down because your body rubs against tiny particles, called molecules, that make up water. That's what happens to a parachute, too! As the parachute falls through the air, it meets resistance from air molecules. This resistance is called drag.

Drag can be a problem when we want trains, planes, or cars to move fast. The more surface area of a vehicle that meets the air, the more drag is created. Aeronautical engineers design vehicles to be as smooth and sleek as possible to help reduce drag. That's why planes and rockets have pointed noses. We call vehicles that are designed to have a minimum amount of drag streamlined. The Concorde airliner is designed to fly faster than the speed of sound. It is shaped like a needle with deltoid (triangle-shaped) wings that reduce the drag on the plane.

The Lifting Power of Air

Have you ever played with a Frisbee[TM]? You may have noticed that its upper surface is curved. That shape is called an airfoil. Airplane wings are airfoils, too. Airfoils make Frisbees[TM] and airplanes rise in the air. When air goes over the longer, upper surface of an airfoil, it moves faster. Faster air has lower pressure. The air under the wing moves more slowly. It has higher pressure, so it pushes up on the airfoil. This rising force is called lift. An airplane has to have enough lift to overcome the force of gravity in order to fly.

DID YOU KNOW??

The science of flight is called aeronautics.

DID YOU KNOW??

In many airplanes today, the engine fuel is stored in the wings.

DID YOU KNOW??

Air is heavy. 14.7 lbs. of air rests on every 1 square inch of Earth!

Vocabulary

Try your Word Power with this Air Power crossword puzzle.

DOWN:

1) This force causes parachutes to fall slowly.

3) Smooth, sleek shape that has little resistance to drag.

4) Triangle-shape.

7) The-- -speed rush of hot air powers a jet engine plane.

ACROSS:

2) Higher air--pushes an airfoil up.

5) A person who designs vehicles and other machines.

6) The power of moving air to push something forward.

8) A shape with a curved upper surface.

9) This plane flies faster than the speed of sound.

[ILLUSTRATION OMITTED]

DID YOU KNOW??

The first helicopter flight in 1907 lasted 20 seconds. The helicopter rose 1 foot in the air.

Weekly Problem

Three parachutists are having a race. The 1st: parachutist jumps from a cliff that is 325 feet high and falls at 25 feet per second. The 2nd jumps from a cliff that is 380 feet high and falls at 20 feet per second. The 3rd jumps from a cliff that is 480 feet high and falls at 30 feet per second.
1) How many seconds will it
take for each one to land?

1st 2nd 3rd
[] [] []

2) After 8 seconds, how high
Will each one be?

1st 2nd 3rd
[] [] []


[ILLUSTRATION OMITTED]

DID YOU KNOW??

A plane takes off into the wind. This gives the wings better lift.

DID YOU KNOW??

The wing span of the Stealth bomber is half the length of a football field!

Writing for Science

Until 1902, no one had ever flown in a machine that was heavier than air and could travel under its own power. In 1903, Orville Wright flew for 12 seconds over the beach at Kitty Hawk, North Carolina. Imagine you are Orville. Write an entry in your diary about what you saw, heard, and felt during those 12 seconds. How was your take off? How did you land?

DID YOU KNOW??

The Wings of the Wright brothers, plane Were made of thin pieces of wood, wire, and cloth!

DID YOU KNOW??

Orville Wright flew the first motor-powered airplane.

He flew it lying down on his stomach.

Challenge

Make an airfoil and see if you can make it rise like an airplane wing.

You need: copy or typing paper, Scissors, tape, a straw

* Cut a piece of paper 8 inches long by 1 1/2 inches wide.

* Draw a line 3 inches from one end and fold on that line.

* Tape the two ends together (see picture).

* Slide the fold of the airfoil onto the straw. Make sure the curved side is away from you.

* Blow hard across the curved side. What happens?

* Now turn the airfoil over and try again. What happens now?

[ILLUSTRATION OMITTED]

DID YOU KNOW??

The idea for hot-air balloons came to the Montgolfier brothers when they watched smoke rise from a fire.

Weekly lab

Parachutes have a lot of drag. Make one and observe how drag works.

You need: 6 pieces of tissue paper, scissors, glue, tape, thread or light string, a small paper or plastic cup

Step 1: Stack 6 pieces of tissue paper.

Step 2: Cut out this parachute shape and trace it onto the stack of tissue paper.

Step 3: Cut out the 6 tissue paper patterns.

Step 4: Spread a thin layer of glue on the left edge of one piece and glue it to right edge of another piece. Don't worry about wrinkles.

Step 5: Continue gluing all the pieces to form a dome. Let it dry.

Step 6: Next cut 6 pieces of thread about 14 inches (35 cm) long.

Step 7: Cut the cup in half across the

Step 8: Tape the ends of each thread to the side of the cup and the dome.

Step 9: Hold your parachute as high as you can and let it drop!

[ILLUSTRATION OMITTED]

DID YOU KNOW??

Andre-Jacques Garnerin invented the parachute while imagining how to escape from a castle where he was a prisoner of war in the 1780's!

DID YOU KNOW??

"Jump jets" are jets that can take off vertically. Some can even fly Backwards!

DID YOU KNOW??

The first passengers in a hot-air balloon in 1783 were a duck, a rooster, and a sheep!

DID YOU KNOW??

"Microlight" planes weigh less than 250 pounds (112 kg), including the engine.

DID YOU KNOW??

"Swing-wing" aircraft have wings that stick out for take-off and landing. They Swing back close to the plane's body to reduce drag during flight.

DID YOU KNOW??

A jet engine sucks in more than 1 ton of air every second. That's enough to fill 2 houses!

Air Power

Background

This issue of Science Weekly focuses on the power of air to move people and machines through the air.

What is Air?

Air is all around us. We sometimes take air for granted because it is invisible and has no taste or smell. Kids sometimes think that air is empty. Air is actually made up of a mixture of gases. About 78% of air is nitrogen, about 20% is oxygen, and 1% is argon. There are trace amounts of helium, neon, methane, and other gases.

Air is heavy because these gases have weight. Even though we can't feel it, air is constantly pressing down on us--14.7 lbs. of air rests on every square inch (or 1.02 kg on every square cm) of the Earth. This press of air is called air pressure. It is easy to demonstrate that air has weight by attaching an uninflated balloon to one end of a yardstick and an inflated balloon to the other end. When you balance the yardstick on the 18-inch mark in the middle, the side with the inflated balloon will sink.

The Power of Moving Air

We become aware of air when it is moving. When the wind blows, we feel it on our skin. If it blows hard enough, we can hear it whistle. We can see it rustle the leaves in the trees and push the clouds across the sky.

In the natural world, many plants, including dandelions and maple trees, rely on the wind to move their seeds. Their seeds are designed to ride on currents of air. Many birds and bats are well-adapted to ride currents of air, too. Birds with long, straight wings that are narrow from front to back, such as hawks and swallows, can soar and glide for long periods of time without flapping their wings.

People have always longed to fly like birds. In the ancient Greek myth of Icarus and Daedalus, a man and his son wear wings made of bird feathers to escape from their island prison. Unfortunately, people cannot fly like birds because we are too heavy. Even if we had feathers, our muscles are not nearly strong enough to lift our heavy bodies.

Hot-air balloons were invented by the Montgolfier brothers in France in 1783. Hot-air balloons use light, hot air to rise but depend on wind to push them across the sky. Kites rely on wind, too, to lift and carry them.

In 1903, the Wright brothers, Orville and Wilbur, were the first humans to fly in a machine that was not powered by wind. They practiced with gliders, but designed and used a small gasoline-powered engine to turn their plane's 2-bladed propellers. The spinning propellers pushed the air to give their plane thrust to move it forward.

Many planes still rely on thrust provided by spinning propellers. In 1937, a British pilot and engineer named Frank Whittle invented the jet engine. Jet engines work by sucking air into the front of the engine where it is then squeezed under great pressure. Then the air is sprayed with fuel, which burns continuously. The hot gases produced this way are blasted out of the back of the engine, pushing it and the plane forward. The first jet airliner was the De Havilland Comet, which took flight in 1949.

The Power of Still Air

In 1787, a Frenchman named Andre-Jacques Garnerin invented the parachute. He leapt from a hot air balloon that floated more than 3,000 feet (925 m) in the air. (That's more than twice the height of the Sears Tower.) He landed safely because his fall was slowed by air.

The force of gravity pulls everything to Earth, including a parachute. As the parachute falls, air gets trapped beneath its canopy. The parachute pushes through the air, but the air resists the passage of the canopy through it. The resistance of the air slows down the parachute. We experience the same phenomenon when we try to run through deep water. The resistance of the water slows us down. That resistance is also known as drag. Aircraft need enough thrust to overcome the drag of the aircraft's body.

Aeronautical engineers are people who design vehicles that travel through air. Aeronautical engineers try to minimize the drag that slows down aircraft. We call aircraft that have pointed noses and sleek forms, to cut through the air smoothly, streamlined.

The body of a Concorde airliner is shaped like a needle, which makes it very streamlined. It also has thin deltoid (triangle-shaped) wings that reduce drag. The Concorde can fly more than twice as fast as the speed of sound and twice as high as ordinary airliners. When it flies at supersonic speed (faster than the speed of sound), it produces a shock wave of air, which we hear as a sonic boom.

The Lifting Power of Air

Airplanes wings have a special shape called an airfoil. An airfoil has a curved upper surface and a flat lower surface. As an airplane wing moves through the air, the air divides to pass around the wing. The air that goes over the top has a longer distance to go (over the curve) than the air passing straight under the wing. Since the air above the wing must travel a longer distance in the same amount of time as the air below the wing, it therefore must go faster.

In 1738, Swiss mathematician Daniel Bernoulli (burr NOO lee) discovered that faster-moving water (and air) has a lower pressure than slower-moving air. This discovery has had great implications on the design of aircraft. It means that the air pressure below a wing is greater than the air pressure above a wing. This greater pressure below forces the wing up. The upward force is called lift. Aeronautical engineers design planes to have enough lift to counter the downward force of gravity.

Airplanes also have elevators that help them climb and descend. The elevators are the horizontal, movable pieces on its tail section. The pilot pulls back on a control column in the cockpit to raise the elevators on the tail. This deflects the flow of air so that it pushes the tail down and makes the nose rise. Pilots control the direction of the airplane in two ways. They turn the plane's rudder, which is the vertical, moveable piece on the tail section, to the left or right. They also move the ailerons, the moveable pieces on the edges of the wings, up and down.

Many Kinds of Airplanes

Airplanes are designed for different uses. Aeronautical engineers often have to make trade-offs between features. The Concorde, for example, has thin wings to make it streamlined for high speed flight. However, because its wings present a low profile in the air, they do not generate as much lift as do the more curved, but less streamlined wings, of the Boeing 747. This means the Concorde needs longer runways to gain enough speed to take off. "Microlight" airplanes that weigh less than 250 lbs. have small, light engines that do not generate a lot of thrust. They have long wings to generate lots of lift, using thrust to its best advantage.

"Swing-wing" aircraft have wings that go straight out to the sides during take-off to generate lift. In flight, they swing back close to the body of the plane to reduce drag.

National Science Education Standards

Unifying Concepts and Processes (K-8)

* Systems, order, and organization

* Evidence, models, and explanation

* Constancy, change, and measurement

* Evolution and equilibrium

* Form and function

Standard A: Science as Inquiry (K-8)

* Abilities necessary to do scientific inquiry

* Understanding about scientific inquiry

Standard B: Physical Science (K-4)

* Properties of objects and materials

* Position and motion of objects (5-8)

* Properties and changes of properties in matter

* Motions and forces

* Transfer of energy

Standard E: Science and Technology (K-4)

* Abilities of technological design

* Understanding about science and technology

* Abilities to distinguish between natural objects and objects made by humans (5-8)

* Abilities of technological design

* Understandings about science and technology

Standard G: History and Nature of Science (K-4)

* Science as a human endeavor (5-8)

* Science as a human endeavor

* History of science

Level Pre-A

Main Concepts: Air is powerful. We can't see air, but it can move things.

Picture Activity

Ask your students if they can see air. Tell them that even though we can not see air, we know that it is there. Have them find some examples of the power of air in the picture on the front page--pushing the hot-air balloon and the kite, blowing on the boat's sail, etc. Ask them how the airplane with propellers moves through the air. Is the wind blowing it or is something else helping it to move? Engines in planes help air to move airplanes. The shape of an airplane's wings also help it to fly.

Vocabulary

Answers: car. Go over all the pictures together first--chair, car, hair, bear, stair. (Note that all the words end in the "r" sound.) Tell them to say each word aloud and to circle the one that does not rhyme with "air."

Weekly Lab

You need: a pencil with an eraser, tape, scissors, and a push pin. (After they cut out their pinwheels, you can also have them glue a plain piece of paper to the back and decorate the outside.) Have them carefully cut along the red diagonal lines just up to the center circle. Next, show them how to match the pictures in the corners with the pictures in the circle. Have them bring over one corner at a time. (The little pictures will be facing each other.) Then have them tape each corner down to the center. Next, with adult supervision, have them push their pins through the red dot in the center of the pinwheel and into the side of their pencil eraser. Tell them that good scientists are always very careful and that they need to handle their push pins safely (or have an adult do this part). Be sure the pushpin goes straight in and not at an angle. The pinwheel should be perpendicular to the pencil for easy spinning. Tell them not to push their pin in all the way (this will allow room for easy movement.) Have them experiment with different ways of making their pinwheels spin (e.g., holding it up to the wind, blowing from different sides, waving the pinwheel, etc.). If their pinwheels do not turn freely, enlarge the hole in the center.

Weekly Problem

Answers: 3 red, 5 green, 2 blue. Ask how many in all. (10).

Storytelling

Ask them to describe where they would go if they had their own private plane. What would they see? What do they think swimming pools, rivers, buildings, and roads will look like from above? How do they think they will feel?

Challenge

You need (for each student): a straw, tape, 2 strips of paper about 1 inch by 5 1/2 inches. In this activity, your students will be making a straw and paper loop glider. Have them tape the ends of their paper strips together to make 2 loops the same size. Show them how to tape the ends of their straw to the insides of the loops, so that both loops are taped to the same side of the straw. Have them experiment launching their gliders with the loops up and then with the loops down. Have them compare the 2 flights.

Home Base

This activity can be done at home and/or in class. Start with 2 identical pieces of paper (copy or notebook paper work well). Ask them to crumple 1 piece into a ball. Have them hold the ball of paper in one hand and the flat sheet of paper in the other. Tell them to hold their arms straight out in front of them and drop the pieces of paper at the same time. Have them guess which paper will fall more slowly. Explain that the molecules in air push up against objects falling through them. Because the flat sheet of paper covers a much bigger area compared to the small ball of paper, more molecules of air are pushing up on the sheet of paper. That is why the flat sheet of paper falls more slowly than the ball of paper.

Level A

Main Concepts: Air is powerful. We can't see air, but it moves things. Airplanes move air to make them fly.

Picture Activity

Ask your students if they can see air. Tell them that even though we can not see air, we know that it is there. Have them find some examples of the power of air in the picture on the front page--pushing the hot-air balloon and the kite, blowing on the boat's sail, etc. Ask them how the airplane with propellers moves through the air. Is the wind blowing it or is something else helping it to move? Engines in planes help air to move airplanes. The shape of an airplane's wings also help it to fly.

Vocabulary

Answers: chair, bear, pear, hair, stair. Go over all the pictures together with your students first--chair, car, hair, door, bear, pear, stair. Note that all the words end in the "r" sound. Ask them if they can think of other words that rhyme with "air."

Weekly Lab

You need: a pencil with an eraser, tape, scissors, and a push pin. (After they cut out their pinwheels, you can also have them glue a plain piece of paper to the back and decorate the outside.) Have them carefully cut along the red diagonal lines just up to the center circle. Next, show them how to match the pictures in the corners with the pictures in the circle. Have them bring over 1 corner at a time. (The little pictures will be facing each other.) Then have them tape each corner down to the center. Next, with adult supervision, have them push their pins through the red dot in the center of the pinwheel and into the side of their pencil eraser. Tell them that good scientists are always very careful and that they need to handle their push pins safely (or have an adult do this part). Be sure the pushpin goes straight in and not at an angle. The pinwheel should be perpendicular to the pencil for easy spinning. Tell them not to push their pin in all the way (this will allow room for easy movement.) Have them experiment with different ways of making their pinwheels spin (e.g., holding it up to the wind, blowing from different sides, waving the pinwheel, etc.). If their pinwheels do not turn freely, enlarge the hole in the center. Also have them try making and experimenting with different sized pinwheels. Have them find out for themselves which takes more effort to turn, a smaller or larger pinwheel. Which one will turn faster in the same amount of wind?

Weekly Problem

Answers: Top row: 3 yellow 4 red 3 yellow Middle row: 5 purple 6 green 5 purple Bottom row: 3 yellow 4 red 3 yellow. Have your students first color in the dots to use as a key. Then have them solve the subtraction problems and color by number.

Writing for Science

Ask them to describe where they would go if they had their own private plane. What would they see? What do they think swimming pools, rivers, buildings, and roads will look like from above? How do they think they will feel? Encourage them to illustrate their stories with "aerial" views. Tell them about "microlight" planes. A typical microlight only weighs about 250 lbs., which is about the combined weight of 5 kids. Only one person can fly in a microlight. People who own microlights can fold them up and put them on top of their cars.

Challenge

You need (for each student): a straw, tape, 2 strips of paper about 1 inch by 5 1/2 inches. In this activity, your students will be making a straw and paper loop glider. Have them tape the ends of their paper strips together to make 2 loops the same size. Show them how to tape the ends of their straw to the insides of the loops, so that both loops are taped to the same side of the straw. Have them experiment launching their gliders with the loops up and then with the loops down. Have them compare the 2 flights. As an extension activity, have them make loops of different widths and lengths. See how the change in size affects the flight of their loop glider. Which combination makes the glider go farthest?

Home Base

This activity can be done at home or in class. Start with 2 identical pieces of paper (copy or notebook paper work well). Ask them to crumple 1 piece into a ball. Have them hold the ball of paper in one hand and the flat sheet of paper in the other. Tell them to hold their arms straight out in front of them and drop the pieces of paper at the same time. Have them guess which paper will fall more slowly. Explain that the molecules in air push up against objects falling through them. Because the flat sheet of paper covers a much bigger area compared to the small ball of paper, more molecules of air are pushing up on the sheet of paper. That is why the flat sheet of paper falls more slowly than the ball of paper.

Level B

Main Concepts: Air is a powerful force. Airplanes move air to fly. A parachute uses still air to slow its fall.

Vocabulary

Answers: 1-f) parachute 2-e) airplane 3-c) helicopter 4-a) stop 5-d) pinwheel 6-b) propeller.

Weekly Lab

After they cut out their pinwheels, you can also have them glue a plain piece of paper to the back and decorate the outside.) Tell them to be sure their pushpin goes straight in and not at an angle. The pinwheel should be perpendicular to the pencil for easy spinning. Tell them not to push their pin in all the way to allow room for easy movement (or have an adult do this part). Have them experiment with different ways of making their pinwheels spin (e.g., holding it up to the wind, blowing from different sides, waving the pinwheel, etc.). If their pinwheels do not turn freely, enlarge the hole in the center. Also have them try making and experimenting with different sized pinwheels. Have them find out for themselves which takes more effort to turn, a smaller or larger pinwheel.

Weekly Problem

Answers: a) 15 miles b) 12 miles c) 7 miles d) 2 miles.

Writing for Science

Ask them to imagine what they would see if they jumped from an airplane over their home or school. What would they hear? How would it feel to be a parachutist? What would it feel like to land? Explain that some parachutists jump from special airplanes for fun. They first take lessons on how to parachute safely and wear their chutes in what looks like a backpack. They fall through the air for several seconds without opening their parachutes, then they pull a cord that opens it. They slow down very suddenly when the parachute first opens. Then, they drift down to Earth.

Challenge

Answers: a) Stealth bomber (1989) b) Hot-air balloon (Montgolfier brothers, 1783) c) Jet airliner (1949) d) Wright brothers' biplane (1903).

Home Base

They will only be using the bottom 1/2 of the cup. After they tape the pieces of thread to the tissue, have them gather all the threads together. Then tape them to the top of the half-cup close together. Have them drop a 2nd half-cup without a parachute for comparison. It will fall much faster. Explain that molecules in the air push up against objects falling through them. The tissue parachute has a big surface, so there are lots of molecules of air pushing on it. That is why the parachute slows the half-cup's fall.

Level C

Main Concepts: Airplane engines push air to fly. Parachutes use air to slow their fall. The shape of an airfoil makes planes rise.

Vocabulary

Answers: 1) thrust 2) airfoil 3) lift 4) drag. Tell your students to use the front page, if they need help.

Weekly Lab

Set up several pairs of chairs and make sure that the strings are tightly stretched. To keep the strings taut, you may want to have someone sit in each chair. To help thread the string through the straw, try looping the string through a paper clip. Then, drop the paper clip through the straw. When the balloons are ready to be launched, have your students predict how far their balloon rockets will go. You can point out that these balloons are streamlined because they are sleek and smooth. A wider, rounder balloon would increase the air resistance and slow the rocket. The air in the balloons provides the thrust that makes them go forward. The string keeps their trajectory straight.

Weekly Problem

Answers: 1) 220 miles 2) 170 miles 3) 105 miles 4) 35 miles.

Writing for Science

See TN Level B--WRITING FOR SCIENCE. In addition, when parachutists land, it is at about 14 miles per hour (which is still pretty fast). They must learn to roll as they land, so they won't hurt themselves.

Challenge

They will only be using the bottom 1/2 of the cup. After they tape the pieces of thread to the tissue, have them gather all the threads together. Then tape these to the top of the half-cup. When they drop the cup without a parachute, it will fall much faster. Explain that molecules in the air push up against objects falling through them. The tissue parachute has a much larger surface than the half-cup, so there are more molecules of air pushing up on the tissue parachute which slows its fall.

Puzzle

Answers: a) Stealth bomber (1989) b) Jet airliner (1949) c) Hot-air balloon (Montgolfier brothers, 1783) d) early Chinese kite (about 400 B.C.) e) Wright brothers' biplane (1903).

Level D

Main Concepts: Airplane engines push air to fly. Parachutes use air to slow their fall. Airfoils use air pressure to make planes rise.

Vocabulary

Answers: 1) thrust 2) airfoil 3) lift 4) drag 5) streamlined 6) deltoid.

Weekly Lab

See TN Level C--WEEKLY LAB. In addition, try inflating the balloon to different sizes to see what happens.

Weekly Problem

Answers: 1) 5 seconds 2) 6 seconds 3) When the 1st one lands, the 2nd will be 30 feet above the ground.

Writing for Science

Ask them to imagine what they would see if they jumped from an airplane over their home or school. How would it feel to be a parachutist? Explain that some parachutists jump from special airplanes for fun. They first learn how to parachute safely. They wear their parachutes in what looks like a backpack. Parachutists usually jump out of an airplane at about 10,000 feet. They fall through the air for several seconds before opening their parachutes, by pulling on a cord. They slow down very suddenly when the parachute first opens. Then, they drift down to Earth. The wind can blow them sideways. When they land, it is at about 14 mph (which is still pretty fast). Parachutists have to learn to roll as they land so they won't get hurt.

Challenge

Encourage your students to blow over the curved side of the airfoil. They also need to aim their breath slightly downward. It may take several tries before their airfoil rises. The airfoil rises because it has a curved upper surface. Since the air is moving quickly over the airfoil, the air pressure on the upper surface is less than it is under the airfoil. That means that the air is pushing up harder from below than it is from above. This is what makes the airfoil (and an airplane wing) rise.

Puzzle

a) Stealth bomber (1989) b) Hot-air balloon (Montgolfier brothers, 1783) c) Fokker triplane (1917) d) early Chinese kite (about 400 B.C.) e) Wright brothers' biplane (1903) f) Jet airliner (1949).

Level E

Main Concepts: Airplane engines push air to fly. Parachutes use air to slow their fall. Airfoils create air pressure differences that make planes rise.

Vocabulary

Answers: DOWN: 1) drag 3) streamlined 4) deltoid 7) high ACROSS: 2) pressure 5) engineer 6) thrust 8) airfoil 9) Concorde.

Weekly Problem

Answers: 1) 1st parachutist-13 seconds, 2nd parachutist-19 seconds, 3rd parachutist-16 seconds 2) 1st parachutist will be at 125 feet off the ground, 2nd parachutist will be at 220 feet, 3rd parachutist will be at 240 feet.

Writing for Science

The Wright brothers' plane was called the Flyer. Orville flew the plane lying down on his stomach. The plane flew 120 feet (37 meters) in 12 seconds, and the brothers made 3 more flights that day. The longest, by Wilbur, was 852 feet (260 meters) in 59 seconds.

Challenge

Encourage your students to blow over the curved side of the airfoil. They also need to aim their breath slightly downward. It may take several tries before their airfoil rises. The airfoil rises because it has a curved upper surface. Since the air is moving quickly over the airfoil, the air pressure on the upper surface is less than it is under the airfoil. That means that the air is pushing up harder from below than it is from above. This is what makes the airfoil (and an airplane wing) rise. When they turn the airfoil around and blow across the flat side, the airfoil will not rise dramatically.

Weekly Lab

Point out that the shape they are tracing is not a simple triangle. The sides are curved. The curves will result in a 3-dimensional dome shape. They will need very little glue to attach these sections to one another. The sides should overlap as little as possible. There will be wrinkles in the paper, but wrinkles and even small tears are alright. Explain that gas molecules in the air push up against objects falling through them. Their tissue parachute has a large surface, so there are lots of molecules of air pushing on it. That is why the parachute slows the cup's fall.

Level F

Main Concepts: Airplane engines use air to provide thrust. Parachutes use air for drag. Airfoils create air pressure differences that provide lift to make planes rise.

Weekly Lab

Point out that the shape they are tracing is not a simple triangle. The sides are curved. The curves will result in a 3-dimensional dome shape. They will need very little glue to attach these sections to one another. The sides should overlap as little as possible. There will be wrinkles in the paper, but wrinkles and even small tears are alright. Explain that gas molecules in the air push up against objects falling through them. Their tissue parachute has a large surface, so there are lots of molecules of air pushing on it. That is why the parachute slows the cup's fall.

Weekly Problem

Answer: 252 mph. The 1st parachute slows the capsule by 30% (600 x .3 = 180 mph) to a speed of 420 mph. The 2nd parachute slows the capsule by 20% (420 x .2 = 84 mph) to a speed of 336 mph. The last parachute slows the capsule by 1/4 (336 x .25 = 84 mph) to a speed of 252 mph.

Writing for Science

The Wright brothers' plane was called the Flyer. Orville flew the plane lying down on his stomach. The plane flew 120 feet (37 meters) in 12 seconds, and the brothers made 3 more flights that day. The longest, by Wilbur, was 852 feet (260 meters) in 59 seconds.

Challenge

Explain that it is important to tape the wing so that it is centered over the straw and is perpendicular to the straw. Remind them to leave about 1 inch of the straw to go beyond the wing for the nose. Ask them to note the shape of the wing. It is an airfoil that will give the plane lift. Small changes can make a big difference in how their planes fly. Encourage them to try to fly their planes with several paper clips in the nose--and to try bending the ailerons and elevators at different angles. They can also crease the rudder vertically and try bending it to the right or left. Both the rudder and the ailerons can make the plane turn.

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

* Blackburn, Ken, Jeff Lammers. Kids Paper Airplane Book, New York: Workman Press, 1996

* Macauley, David. The Way Things Work. New York: Houghton Mifflin Company, 1998

* Pallis, Jani Macari (ed.) The Big Book of Air and Space Flight Activities. Columbus, OH: McGraw-Hill, 2000

* Schmidt, Norman. Best Ever Paper Airplanes. New York: Sterling Publications, 1995

* Smith, Miranda. Flight and Flying Machines. New York: Dorling Kindersley, 1990

* Taylor, Barbara. Up, Up, and Away: The Science of Flight. New York: Random House, 1990

Internet Resources

The K-8 Aeronautics Internet Textbook--http://wings.avkids.com

U.S, Air Force Museum--http://www.wpafb.af.mil/museum/edu/soar2.htm

National Air and Space Museum--http://www.nasm.edu/nasm/NASMexh.html

All about the Concorde Airplane--http://www.concordesst.com

Science Museum of London--http://www.sciencemuseum.org.uk/on-line/flight/flight/history.asp

Science Museum of Minnesota "Air Cluster"--http://www.smm.org/sln/tf/nav/aircluster.html

More on the Wright Brothers' Planes--http://www.first-to-fly.com/

The History of Kites--http:/www.geocities.com/Colosseum/4569/history. htm

The History of "Stealthy" Bombers--http://www.discovery.com/area/technology/b2/history.html

Fabrics and Aviation (photos)--http://www.fibersource.com/textile_flight/flight.htm

Interesting "stuff" from How Stuff Works--http://www.howstuffworks.com/airplane.htm http://www.howstuffworks.com/hot-air-balloomhtm http://www.howstuffworks.com/3d/turbine-3d.htm

Materials Needed for Issue 16--Sound

Pre-A, A--tape, paper cups, spoons, oatmeal boxes, small shoe boxes, candy or paper clips, rubber bands, potato chip bags plastic bowls, uncooked rice or peas, wax paper, salt, thin cookie sheets

B--12-inch hard plastic rulers, comic strips from newspapers, tape, paper cups, spoons, oatmeal boxes, small shoe boxes, candy or paper clips, rubber bands, potato chip bags, plastic bowls, uncooked rice or peas, wax paper, salt, thin cookie sheets, bottles

C--12-inch hard plastic rulers, comic strips from newspapers, potato chip bags, plastic bowls, salt, uncooked rice or peas, wax paper, thin cookie sheets, bottles

D--empty aluminum cans, marbles, aluminum foil, newspapers, comic strips from newspapers, 12-inch hard plastic rulers, potato chip bags, plastic bowls, uncooked rice or peas, wax paper, salt, thin cookie sheets, bottles

E--empty aluminum cans, marbles, aluminum foil, newspapers, comic strips from newspapers, 12-inch hard plastic rulers

F--comic strips from newspapers, 12-inch hard plastic rulers
COPYRIGHT 2002 Science Weekly, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2002 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Science Weekly
Date:Apr 12, 2002
Words:6301
Previous Article:Fabrics and fibers.
Next Article:Sound.
Topics:


Related Articles
WAR TAKES TIME, SAYS HISTORIAN; EXPECTATIONS UNREALISTIC IN KOSOVO, SCHOLAR FINDS.
Air Power: The Men, Machines, and Ideas That Revolutionized War, from Kitty Hawk to Gulf War II.
American Carrier Air Power at the Dawn of a New Century.
Billy Mitchell.

Terms of use | Privacy policy | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters