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   Air and Aerodynamics
           Flight
AIR AND AERODYNAMICS
         TOPIC A
   Describe the
  properties of air
        and
the interactions of
 air with objects in
       flight.
          SLE #1
PROVIDE EVIDENCE THAT AIR
    TAKES UP SPACE AND
   EXERTS PRESSURE, AND
   IDENTIFY EXAMPLES OF
    THESE PROPERTIES IN
  EVERYDAY APPLICATIONS
         PROPERTIES
•   Air has mass
    We saw that when a balloon is filled with air, it is heavier than when it is deflated.
•   Air takes up space
    In our experiments, we observed that a jar that looked empty was actually full of air because it kept the water from easily
    entering the jar through the funnel. If there was another hole in the stopper, the water went in easily as the air had
    somewhere to go. We also see evidence of air when we blow up a balloon, inside bike and car tires, turn on a fan, and
    when we breathe.
•   Air exerts pressure
    We covered a ruler on the table with the newspaper and then we tried to lift the paper off the table by hitting the end of
    the ruler but the weight of the air pressing down on the newspaper did not let the paper move. The pressure of air is
    about one kg per square cm. That means your open hand is actually holding up about 50 kg of air! Air can also hold up
    a glass of water upside down when you cover it with a piece of cardboard.
•   Air has the power to hold things up
•   Air is invisible
    We looked inside a box but we couldn’t see anything. After, we found out that air is everywhere and although we can’t
    see it, we can feel it when we move our hands and see evidence of it when leaves blow or a flag moves.
•   Air can be compressed
    We used the plungers to compress air.
          Our Air Experiments
• Air is Everywhere – (Funnel, jar, plasticine,
  coloured water) Air has the power to hold things up.
• Fill It Up Please – (Two flasks, funnels,
  one hole stopper, two hole stopper, water,
  beaker) Air has the power to hold things up.
• Diving Paper – (Bowl, beaker, water,
  paper) Air has the power to hold things up.
• Huff N’ Puff – (Balloon, pop bottle) Air takes up
  space
- A-Weigh We Go – Air has mass/weight.




- Drinking Straws (Straws, glass, water)
- Crushing Air (Water bottle, hot water, cold
water) – Warming the bottle caused the air to expand – some air
left the bottle. When we cooled it, the air inside condensed. The air
pressure inside was lower and the air pressure outside the bottle was
cooler and heavier (higher air pressure), so it pushed the bottle and
crushed it.
          SLE #2
PROVIDE EVIDENCE THAT AIR
   TAKES UP SPACE AND
  EXERTS PRESSURE, AND
  IDENTIFY EXAMPLES OF
   THESE PROPERTIES IN
 EVERYDAY APPLICATIONS.
Air is fluid and is capable of being
  compressed Expt. – Taking the Plunge –                       We covered the plunger with
                   our finger and tried to compress the air into a smaller area. It got harder
                   to push as the air got more compressed. Gas particles are quite far apart
                   and can be compressed (squeezed closer together to occupy a smaller
                   volume) by applying pressure.
Balloon Rockets
• We learned that when blowing up a balloon, you are
  squeezing or compressing the air inside of it. When you
  let the balloon go, the air is forced out through the neck.
  This force pushes the balloon in the opposite direction.
• Everyday uses of compressed air: tire pumps, ball
  pumps, paintball guns, lungs, pressurized water pump in
  our houses, nail guns, jack hammers, oxygen tank, air
  compressors
Adjust the Volume
• We used pop bottles, hot and cold water,
  thermometers, and balloons. The amount
  of air in the bottle stayed the same. The
  water surrounding the bottles changed the
  air temperature in the bottles causing the
  air to expand and contract. The hot air
  expanded and needed more space
  causing the balloon to inflate. The cold air
  condensed (taking up less space), and the
  balloon deflated. A thermometer works on
  this same principle.
   The Great Squirt Challenge
As we blew into the tubing, we compressed
the air in the flask by adding more air. This
increased the air pressure in the flask. Due
to compression, the water was forced out of
the medicine dropper nozzle. When the air
in the flask could not be compressed
anymore, the water was forced up the tube.
          SLE #3
DESCRIBE AND DEMONSTRATE
   INSTANCES IN WHICH AIR
     MOVEMENT ACROSS A
 SURFACE RESULTS IN LIFT –
   BERNOULLI’S PRINCIPLE.
• Air movement across a surface results in
  lift ….

          Bernoulli’s Principle
                               •Blow over the top of a
                               strip of paper and it
                               will rise. — Bernoulli’s
                               principle
Our Experiments
Let It Shine          – candle, straw, jar, lid, plasticine
(The air moving around the can is at a lower pressure than
the still air. This low pressure moving air is pushed quickly
around the can towards the flame by the still air – high
pressure.)
Ball in a Funnel – We held the funnel upright and put a ping
  pong ball in it. We blew on the stem of the funnel. We couldn’t
  blow the ball out because the air moving around the ball is moving
  faster than the surrounding air. The moving air created a low
  pressure area and the higher pressure of the surrounding air pushed
  against the ball and kept it in the funnel.




Lift Off – We blew over a piece of folded and taped paper.   The fast
  moving air created an air of pressure lower than the air that moved
  more slowly. The paper was forced up by higher atmospheric
  pressure known as LIFT.
The Fastest Spray in the West – We cut a straw
in half and put one half in a glass of water. With the other
half, we blew into it across the other piece of straw. The
higher pressure of the atmosphere pushed down on the
surface of the water forcing the water up the straw toward
the lower pressure created by the fast moving air at the top.
When the water rose to the mouth of the straw, it was
sprayed away in the stream of fast moving air. Paint
sprayers work this way.
                            SLE #4
  RECOGNIZE THAT IN ORDER
     FOR DEVICES OR LIVING
   THINGS TO FLY, THEY MUST
    HAVE SUFFICIENT LIFT TO
  OVERCOME THE DOWNWARD
      FORCE OF GRAVITY.
Bird and bats have movable wings that change shape during flight to
maximize efficiency.
Some insects have very thin strong wings that beat very fast - over 400
times a second for mosquitoes.
•       In order for devices or living things to fly,
        they must have sufficient lift to overcome
        the downward force of gravity.
    1. If lift becomes greater than mass, the plane
        ascends.
    2. If thrust becomes greater than drag, the
        plane goes faster.
    3. If lift, mass, thrust, and drag become equal,
        the plane would hover … would maintain the
        same speed and the same altitude
        (theoretically).
    4. If thrust becomes less than drag, the plane
        slows down.
    5. If lift becomes less than mass, the plane
        descends.
       LIFT




                THRUST


DRAG




       WEIGHT
          SLE #5 & #6


IDENTIFY ADAPTATIONS THAT
 ENABLE BIRDS AND INSECTS
          TO FLY.




 DESCRIBE THE MEANS OF
  PROPULSION FOR FLYING
ANIMALS AND FOR AIRCRAFT.
   Identify adaptations that
      enable birds and
        insects to fly.
Wings – The wings are connected to powerful chest muscles.
    The wings are curved on top and are almost flat on the
    bottom. This shape gives lift as the bird flies through the air.
Feathers – The stiff flight feathers on the wings are hollow
    and light and their shaft is not centered so that they overlap.
    The shaft of the feather is made of a tough materials called
    keratin making the feather stiff but flexible.
Skeleton – Bones are hollow or partially hollow making
    them light but strong.
Muscles – Large pectoral muscles generate the
power to flap the wings. Muscles do not tire quickly.
Breathing system – Lungs are connected to a
network of air sacks that fill up with air helping to provide
the body with a large amount of oxygen used during
flight.
Propulsion: Birds use their legs and wings to take
off. Airplanes have jet engines or propellers to help
them take off.
• Birds and insects flap wings and use thermal
  rising air to fly.
• Flying squirrels glide down, not fly.
• Planes push air backward over fixed wings with
  prop or jet engine.
           SLE #7




      RECOGNIZE THAT
 STREAMLINING REDUCES DRAG,
 AND PREDICT THE EFFECTS OF
 SPECIFIC DESIGN CHANGES ON
THE DRAG OF A MODEL AIRCRAFT
  OR AIRCRAFT COMPONENTS.
  • Streamlining reduces drag




•The part that catches on the air causes drag.
•Put a hand out window of a fast moving car and experiment with
the different hand shapes.
      Oxidation of
      Alanna’s
      apple      SLE #8

    RECOGNIZE THAT AIR IS
   COMPOSED OF DIFFERENT
GASES, AND IDENTIFY EVIDENCE
     FOR DIFFERENT GASES.
   EXAMPLE EVIDENCE MIGHT
 INCLUDE: EFFECTS ON FLAMES,
THE ‘USING UP’ OF A PARTICULAR
  GAS BY BURNING OR RUSTING,
     ANIMAL NEEDS FOR AIR
          EXCHANGE.
                       Fire needs oxygen to burn.
                                                     Blowing CO2 into clear lime water
                                                     turns it milky-looking.
Rusting of the steel
wool used up 1/5 of
the oxygen.

                                Carbon Dioxide put
                                out the flame.




Carbon Dioxide is heavier
        than air.
• Air is composed of different gases.
                                        Nitrogen 78.09%


                                        Oxygen 20.9%


                                        Argon 0.93%


                                        CO2 +other gases
                                        0.042%
                 Our experiments
1. Fruity Oxidation – Oxygen in the air reacts with the
    chemicals on the surface of an object. The oxygen replaces other
    substances. The clue to the presence of oxygen is a brownish
    colour. To stop fruit from rapid oxidation: leave the peel on,
    refrigerate it, cover the fruit in ascorbic acid like lemon juice,
    and/or cover with plastic wrap

2. Gone to Rust – We put wet steel wool in the top of a test
    tube and then inverted it into a beaker of water. After one day,
    some of the steel wool was rusted and about 1/5 of the test tube
    had water in it. Rusting uses up oxygen and our air is about 1/5
    oxygen so once the oxygen was used up, no more rusting took
    place. Paint, oil, grease, galvanizing (covering with zinc metal)
    are effective ways of protecting iron.
  How does an airplane take off? 1

• When an aircraft moves into the wind, the
  wings cut the airflow in half.
• Some air travels above the wing, some air
  travels below the wing.
• Plane wings are build to be curved on top
  and flat on the bottom.
  How does an airplane take off? 2
• The wind, or air stream, flowing over the
  wing travels a different path from air
  traveling under the wing.
• This difference in the path of the wind,
  creates lower air pressure above the wing.
  The higher air pressure under the wing lifts
  the plane into the air creating lift.
  How does an airplane take off? 3

• When there is enough lift to overcome
  gravity, the plane takes off.
• All the time, the plane is being slowed
  down by having to push through the air.
• This is called drag, and the engines have
  to overcome it.
  How does an airplane take off? 4

• As long as the plane continues to move forward
  at a fast enough speed, the plane continues to
  fly.
• Planes use engines to move quickly down the
  runway to create the lift for take off.
• Helicopters rotate their wings (or blades). The
  rotating motion forces air past the wings creating
  lift.

				
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