Air + Plane

AST 406

ChallengeChallenge

To design and make a better airplane;To design and make a better airplane; To understand the atmosphere better;To understand the atmosphere better; To understand how air flows;To understand how air flows; To understand how weather affects air To understand how weather affects air

travel;travel;

Activity: Make a PlaneActivity: Make a Plane

Take a piece of paper and make an airplane Take a piece of paper and make an airplane that you think will fly the farthest;that you think will fly the farthest;

What makes a plane fly farther?What makes a plane fly farther? What makes a plane fly straighter?What makes a plane fly straighter? Suggest characteristics of a good paper Suggest characteristics of a good paper

airplaneairplane

Paper Airplane RubricPaper Airplane RubricPropertyProperty Desired Desired

DesignDesign Aerodynamic – delta shapeAerodynamic – delta shapeControl of air movement over wingsControl of air movement over wingsHelps plane move in desired directionHelps plane move in desired direction

Wing AreaWing Area MaximumMaximum

MassMass MinimalMinimalWeight is balanced throughoutWeight is balanced throughout

MaterialMaterial Keeps shapeKeeps shape

LaunchLaunch Throw forward/up from centre of gravityThrow forward/up from centre of gravity

Atmosphere The atmosphere is the layer of air The atmosphere is the layer of air

surrounding the earth;surrounding the earth; Air is the mixture of gases that make up the Air is the mixture of gases that make up the

atmosphere;atmosphere; Air is ~80% Nitrogen gas (NAir is ~80% Nitrogen gas (N2) and ~20% ) and ~20%

oxygen (Ooxygen (O2). There are also small amounts of water

vapour (H2O), Carbon Dioxide (CO2), and Argon (Ar);

Atmospheric PressureAtmospheric Pressure

Air has mass;Air has mass; Atmospheric pressure is the weight, or force Atmospheric pressure is the weight, or force

down, of the air in the atmosphere;down, of the air in the atmosphere; Pressure = Force/Area (Pascal or Pa);Pressure = Force/Area (Pascal or Pa); 1 Pa = 1 Newton of Force on 1 m1 Pa = 1 Newton of Force on 1 m22;; Atmospheric pressure is about 101300 Pa Atmospheric pressure is about 101300 Pa

or 101.3 kPa (kiloPascal);or 101.3 kPa (kiloPascal);

High and Low PressureHigh and Low Pressure

Greater atmospheric pressure means that Greater atmospheric pressure means that there are more particles in a volume of air;there are more particles in a volume of air;

Less particles = less pressure;Less particles = less pressure; Warmer air rises, the particles move faster Warmer air rises, the particles move faster

and farther apart; thus it has a lower and farther apart; thus it has a lower pressure than cooler air;pressure than cooler air;

Air particles move from zones of high Air particles move from zones of high pressure (with lots of particles) to zones of pressure (with lots of particles) to zones of low pressure (fewer particles)low pressure (fewer particles)

Layers of Air

ActivityActivity

Air pressure demonstration with candle in Air pressure demonstration with candle in beaker beaker

Workbook, Page 117 – 118Workbook, Page 117 – 118

Air Circulation

Air masses move around because of the Air masses move around because of the different densities and temperatures of air different densities and temperatures of air masses around the world due to: masses around the world due to: – Location – above water/landLocation – above water/land– SeasonSeason– Time of dayTime of day– Rotation of the EarthRotation of the Earth

This causes patterns to emerge;This causes patterns to emerge; Air circulates in specific global movements;Air circulates in specific global movements;

Weather PatternsWeather Patterns

Globally – prevailing wind currentsGlobally – prevailing wind currents Continentally – warm/cold air masses move Continentally – warm/cold air masses move

in as fronts depending on pressurein as fronts depending on pressure Locally – Air heats up and rises, cool air Locally – Air heats up and rises, cool air

takes its place creating breezes.takes its place creating breezes.

Depression/Anti-Cyclone

Depression - DDepression - D– low air pressure - Llow air pressure - L– cloudy skiescloudy skies– precipitation – rain, snowprecipitation – rain, snow

Anti-cyclone - AAnti-cyclone - A– high air pressure – Hhigh air pressure – H– clear skiesclear skies– sunny, drier weathersunny, drier weather

Cold/Warm Fronts

A Mighty Wind Prevailing winds are major air currents that Prevailing winds are major air currents that

blow in a given direction according to global blow in a given direction according to global patterns of movement;patterns of movement;

An air mass is a large expanse of the An air mass is a large expanse of the atmosphere with the same temperature, atmosphere with the same temperature, pressure and humidity (water content);pressure and humidity (water content);

Anti-cyclone: an area of air circulation Anti-cyclone: an area of air circulation surrounding a high pressure centre.surrounding a high pressure centre.

Depression: an area of air circulation Depression: an area of air circulation surrounding a low pressure centre;surrounding a low pressure centre;

Cyclone: a tropical storm with violent winds Cyclone: a tropical storm with violent winds revolving around an area of low pressure;revolving around an area of low pressure;

Air Cells Air that has been warmed at the Equator becomes Air that has been warmed at the Equator becomes

lighter and less dense;lighter and less dense; It moves towards the North and South Poles;It moves towards the North and South Poles; Air that has been cooled at the Poles moves Air that has been cooled at the Poles moves

closer to the Earth’s surface and replaces the closer to the Earth’s surface and replaces the warmer air;warmer air;

These circulation loops are called cells;These circulation loops are called cells;

Issues in Atmosphere Research

Wind energyWind energy Smog = Smoke + FogSmog = Smoke + Fog Thinning of the Thinning of the Ozone layer Pollution of the atmospherePollution of the atmosphere Greenhouse Gas EffectGreenhouse Gas Effect Climate change/Global warmingClimate change/Global warming Ottawa Valley Weather Change

Liquid AirLiquid Air

Air can be thought of as a liquid;Air can be thought of as a liquid; They both flow;They both flow; The greater the depth, the greater the The greater the depth, the greater the

pressurepressure Higher density = higher pressure and v.v.Higher density = higher pressure and v.v.

Gas

In a contained gas, the pressure depends In a contained gas, the pressure depends on the number of collisions between the gas on the number of collisions between the gas particles and the container;particles and the container;

The more collisions, the greater the The more collisions, the greater the pressure;pressure;Effect on Pressure Closed Container Open Container

As Temp increases Pressure increases Pressure decreases

ActivityActivity

Workbook, page 123-124;Workbook, page 123-124; Textbook, page 233-239;Textbook, page 233-239; Balloon blow up!Balloon blow up!

Pascal’s Principle

An increase in the pressure in an enclosed An increase in the pressure in an enclosed fluid is transmitted in all directions;fluid is transmitted in all directions;

E.g. the pressure of air in a car tire is the E.g. the pressure of air in a car tire is the same everywhere against the walls of the same everywhere against the walls of the tire;tire;

The brake system of a car uses Pascal’s The brake system of a car uses Pascal’s principle when the fluid is pushed from the principle when the fluid is pushed from the pedal to the brakes;pedal to the brakes;

Hydraulic Lift

Hydraulic Force ChangeHydraulic Force ChangePressure 1 Pressure 2Force1/Area1 = Force2/Area2

Given Area2 = 2 (Area1)

Force/Area1 = Force2/2 Area1

Cross Multiply

2Area1/Area1x Force1 = Force2

2Force1 = Force2

Thus Force2 = Two times Force1

PressurePressure Pressure is a force applied over an area.Pressure is a force applied over an area. Pressure (Pascal) = Pressure (Pascal) = Force (Newtons)Force (Newtons) Area (mArea (m22)) P = P = FF AA What is the pressure of 5 Newtons of Force What is the pressure of 5 Newtons of Force

applied over a 4 mapplied over a 4 m22 area? area? P = P = 5.0 N5.0 N = 1.25 Pa = 1.25 Pa 4 m4 m22

So What is Force?

Force is a push or pull that can change the Force is a push or pull that can change the motion of an object;motion of an object;

It can:It can:– move a stopped object;move a stopped object;– slow down a moving object – deccelerate;slow down a moving object – deccelerate;– speed up a moving object - accelerate;speed up a moving object - accelerate;– it can change the direction of an object;it can change the direction of an object;– it can support an object;it can support an object;

Force of Gravity, FForce of Gravity, Fgg

FFgg = mg = mg where m is mass of object in kgwhere m is mass of object in kg where g is the attraction due to gravitywhere g is the attraction due to gravity g = 9.81 N/kg (m/sg = 9.81 N/kg (m/s22)) E.g. Weight of 5 kg curling stoneE.g. Weight of 5 kg curling stone FFgg = mg = 5 kg x 9.81 N/kg = mg = 5 kg x 9.81 N/kg = 49.05 N down= 49.05 N down

Resultant Force

When you add two or more forces together, When you add two or more forces together, the overall force, or net force is called the the overall force, or net force is called the Resultant Force.Resultant Force.

Net Force =Net Force = 20N up 20N up – – 20 N down20 N down 0 N 0 N

Force Arrows

Forces can be represented by arrows;Forces can be represented by arrows; The The Resultant Force = 5N Left; = 5N Left;

Bernouilli’s Principle

The higher the speed of a fluid, the lower the The higher the speed of a fluid, the lower the pressure and vice versa;pressure and vice versa;

Air particles that pass over an airplane wing Air particles that pass over an airplane wing have to move faster than air particles below have to move faster than air particles below the wing in order to avoid a vacuum;the wing in order to avoid a vacuum;

These faster air particles exert less pressure These faster air particles exert less pressure down compared to the pressure up;down compared to the pressure up;

This creates an overall upwards force or a This creates an overall upwards force or a Buoyant Force, FBuoyant Force, Fbb – or LIFT. – or LIFT.

Bernouilli Creates LiftBernouilli Creates Lift

Archimedes’ Principle

An object immersed in a fluid is subjected to An object immersed in a fluid is subjected to a a buoyant (floating) force, F (floating) force, Fbb, EQUAL to the , EQUAL to the weight of the fluid displaced by the object;weight of the fluid displaced by the object;

The fluid can be air, so:The fluid can be air, so:– An object floats UP if its weight is less than FAn object floats UP if its weight is less than Fbb

– An object remains at level if its weight = FAn object remains at level if its weight = Fbb

– An object sinks if its weight is more than FAn object sinks if its weight is more than Fbb

Archimedes Lifts UpArchimedes Lifts Up

The Big ExplanationThe Big Explanation Airplanes fly because the shape of the wing Airplanes fly because the shape of the wing

causes air to pass more quickly over the upper causes air to pass more quickly over the upper side of the wing(s); side of the wing(s);

The faster flowing air creates an area of lesser air The faster flowing air creates an area of lesser air pressure;pressure;

Since this is less than the normal air pressure, Since this is less than the normal air pressure, LIFT is created;LIFT is created;

This creates a Buoyant Force that lifts the plane This creates a Buoyant Force that lifts the plane up;up;

Various control mechanisms add stability to a Various control mechanisms add stability to a plane.plane.

Airplane DeviationsAirplane Deviations

Airplane ControlsAirplane Controls

Activity

Textbook: Chapter 7 Review: pp 246-249: Q. 1-9, 12-14, 21-32 Workbook: Page 121-122 Construct Paper Airplanes: Plan A: Plan A Plan B: Plan B Plan C: Plan C

Design a Better PlaneDesign a Better Plane

With our class Rubric, make your plane;With our class Rubric, make your plane; Calculate the total area of wing space on Calculate the total area of wing space on

your airplane;your airplane; Determine the mass of the plane;Determine the mass of the plane; Calculate the wing area : mass ratio;Calculate the wing area : mass ratio; Each student will make a Multi-View drawing Each student will make a Multi-View drawing

of his/her plane with side, front and of his/her plane with side, front and overhead views;overhead views;

The ClassicThe Classic

ActivityActivity Workbook: pages 45-46;Workbook: pages 45-46; Textbook: pages 79-87;Textbook: pages 79-87; Complex TasksComplex Tasks Boat race Mouse Trap CarBoat race Mouse Trap Car DesertificationDesertification Carbon TaxCarbon Tax Global Warming – UNGlobal Warming – UN Skeptical ScienceSkeptical Science