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Non-Terrestrial Non-Terrestrial TransportationTransportation

BoatsBoats

Rafts, Sailboats, Ships, & Rafts, Sailboats, Ships, & HydrofoilsHydrofoils

AircraftAircraft

Planes, Passenger Jets, Planes, Passenger Jets, HelicoptersHelicopters

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Blowing on paperBlowing on paper

Buoyancy Kit (tin foil, Buoyancy Kit (tin foil, washers)washers)

Cartesian DiverCartesian Diver

Blower and Ping PongBlower and Ping Pong

Sailboat and TrackSailboat and Track

SpoonSpoon

FairyFairy

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Early BoatsEarly Boats Hollowed out Hollowed out

logslogs Reed raftsReed rafts

www.tulsaweb.com

Pirogue

Redwood Grove, Los Altos

Pronounced: \pē-rōg\

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Overcoming Overcoming GravityGravity

Gravity acts the same on all Gravity acts the same on all objects - exerts greater forces on objects - exerts greater forces on larger masses and smaller forces larger masses and smaller forces on less massive objects such that on less massive objects such that the downward acceleration is the the downward acceleration is the

same for all objectssame for all objects

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Objects suspended in Objects suspended in fluids (air and water)fluids (air and water)

Buoyancy Force counteracts Buoyancy Force counteracts the weight of the object:the weight of the object:

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mg = Fbuoyancy

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Fluids exert pressureFluids exert pressure

Atmosphere at sea level Atmosphere at sea level exerts 14.7 psi (lbs/inexerts 14.7 psi (lbs/in22) in all ) in all

directions due to gravity directions due to gravity pulling down on the column of pulling down on the column of

air above our heads.air above our heads.

Pressure decreases at higher Pressure decreases at higher elevations.elevations.

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Water not movingWater not moving

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Forces due to pressure = Net Buoyant ForceNet Buoyant Force = Weight of water

Water not movingWater not moving

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Forces due to pressure have not changedNet Buoyant Force = Weight of water displaced

Replace water with objectReplace water with object

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If weight of object < Fb (object rises)If weight of object < Fb (object rises)If weight of object > Fb (object sinks)If weight of object > Fb (object sinks)

Archimedes and BuoyancyArchimedes and Buoyancyi.e. some things fall “up”!i.e. some things fall “up”!

Before Before discovering the discovering the Lever and the Screw Lever and the Screw for lifting water, for lifting water, ArchimedesArchimedes discovered discovered buoyancy.buoyancy.

Archimedes Principle states that the buoyant force on a submerged object is equal to the weight of the fluid that is displaced by the object.

This Concept is best This Concept is best seen with Hot Air or seen with Hot Air or

Helium BalloonsHelium BalloonsThe balloon rises because the weight of the balloon, gondola, and the internal gas is less than the air displaced by the balloon.

This is called upthrust.

What would you weigh if What would you weigh if fully submerged in water?fully submerged in water?

(Your weight – the wt. of the water displaced)(Your weight – the wt. of the water displaced)

100 lbs. 100 lbs.

What figure weighs more in the pool?

Cartesian DiverCartesian Diver

By squeezing the By squeezing the bottle the pressure bottle the pressure increases. The air in increases. The air in the condiment the condiment package compresses, package compresses, lowering its volume. lowering its volume.

Less water is Less water is displaced if the displaced if the condiment package is condiment package is compressed, making compressed, making the package less the package less buoyant.buoyant.

http://www.sciencetoymaker.org/diver

Water going vessels can be Water going vessels can be very heavy as long as they very heavy as long as they

displace enough waterdisplace enough water

The vessel will The vessel will float if it displaces float if it displaces water equal to the water equal to the weight of the boat weight of the boat (including cargo). It (including cargo). It must do this without must do this without taking water over the taking water over the sidessides

The Ice Breaker – has an armored steel hullwww.tq-international.co

Materials that are denser than water such as steel can be made to float on water as long as

the steel object can displace an amount of water equal to its weight.

Many Civil Engineering programs build and compete in a Concrete Canoe event.

http://uwnews.org

Three similar sized pieces Three similar sized pieces of tin foilof tin foil

One floatsOne floats One sinksOne sinks One appears One appears

suspendedsuspended

What’s the difference between them?

The Accepted The Accepted Anthropological Map Anthropological Map

Showing Migration of Homo Showing Migration of Homo Sapiens Sapiens

Drawbacks with Drawbacks with Exploration Over LandExploration Over Land

Restricted by Land (a small Restricted by Land (a small percentage of our planet – 29%)percentage of our planet – 29%)

Terrain constraints (mountains, Terrain constraints (mountains, deserts, rivers)deserts, rivers)

EnemiesEnemies Reliance on stock animalsReliance on stock animals High maintenance wagonsHigh maintenance wagons

Benefits and Challenges Benefits and Challenges with Exploration over with Exploration over

WaterWater

Greater mobilityGreater mobility RiskierRiskier Powered by WindPowered by Wind Density of salt water allows large Density of salt water allows large

vessels to floatvessels to float Navigation is difficultNavigation is difficult Usually capital IntensiveUsually capital Intensive

Propelling Boats and Propelling Boats and AircraftAircraft

Oars – for every Oars – for every force there is an force there is an equal and opposite equal and opposite force. force.

Action-Action-ReactionReaction

SailsSails PropellersPropellers AirfoilsAirfoils

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Propellers are FansPropellers are Fans

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HelicoptersHelicopters

http://science.howstuffworks.com/helicopter.htm

WingsWings Airplane Airplane

wings exert a wings exert a downward downward force on the force on the air. The air air. The air pushes up on pushes up on the wing with the wing with an equal an equal force.force.

http://www.seed.slb.com/en/scictr/watch/sailing/index.htmUmbrella Animation

AirfoilAirfoil

A surface designed to produce A surface designed to produce lift from the movement of air over it. lift from the movement of air over it. http://www.aircommand.com

It is the Coanda Effect that gives the fluid the tendency to follow the contour of the upper surface rather than traveling in a straight line. Wikipedia

The Coanda EffectThe Coanda Effect

http://www.allstar.fiu.edu/AERO/airflylvl3.htm

Newton’s 3rd law indicates that the fluid forces the object to the right as it travels along the surface to the left.

Fluid flow

Getting Lift with Getting Lift with AirplanesAirplanes

http://howthingswork.virginia.edu/airplanes.htmlA really good explanation.http://www.allstar.fiu.edu/AERO/airflylvl3.htmA much more detailed explanation.

Lift comes from the air around the wing that is diverted downward.

LIFT: Vertical forceDRAG: Horizontal force

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Would this Airfoil Would this Airfoil Produce Lift?Produce Lift?

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Yes, but drag force isexcessive.

The four forcesThe four forces

LiftLift DragDrag WeightWeight ThrustThrust

http://www.eng.fsu.edu/~ugartjo/Drag.htm

Sailing on a Tack (against Sailing on a Tack (against the wind)the wind)

http://sail-boats.suite101.com

Sailboat DemonstrationSailboat Demonstration

Blow air at a 45Blow air at a 4500 angle of attack angle of attack to show that the pulling force is to show that the pulling force is greater than the pushing force, greater than the pushing force, producing a net force in the producing a net force in the windward directionwindward direction

http://www.seed.slb.com/en/scictr/watch/sailing/index.htmGood Animation of Sails and angle of attack

As air moves faster its As air moves faster its pressure decreases.pressure decreases.

Throwing a curve ball Throwing a curve ball as demonstrated by a as demonstrated by a good pitchergood pitcher

Shower Curtain Shower Curtain problemproblem

Blowing air across Blowing air across paper to make is risepaper to make is rise

Blow Dryer and ping Blow Dryer and ping pong trickpong trick

http://wings.avkids.com/Book/Sports/instructor/curveball-01.html

Propellers have the shape Propellers have the shape of airfoilsof airfoils

http://www.athropolis.com/

Forces from Ailerons and Forces from Ailerons and ElevatorsElevators

A lowered Aileron A lowered Aileron produces Lift, produces Lift, while a raised while a raised Aileron reduces Aileron reduces Lift. The two Lift. The two Ailerons make the Ailerons make the aircraft roll.aircraft roll.

Elevators are at Elevators are at the rear and the rear and control the pitch.control the pitch.

http://en.wikipedia.org/wiki/AileronA good animation here.

http://en.wikipedia.org/wiki/Elevator_(aircraft)

Plane ComponentsPlane Components

http://www.centennialofflight.gov/about/index.htm

HydrofoilHydrofoil Hydrofoils Hydrofoils

are used to are used to ferry people ferry people across the across the English English Channel.Channel.The hydrofoils

produce lift, raising the boat out of the water. Once above the surface, the boat can skim over the top as it is relatively unaffected by waves.

Surface Piercing Foil follows the contours of the waves.

www.maths.otago.ac.nz

http://www.hydrofoil.com/hitest/reference.html

The hydrofoil in inherently stable because when it leans to one side more of the foil on the low side is submerged, increasing the lift on that side. Thus the boat ‘rights’ itself.

Also this hydrofoil follows the contours of the waves. When it travels into a wave, more the foil goes underwater giving the boat greater lift. When it travels out of a wave, less of the foil is underwater, therefore the lift decreases.

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How do spacecraft maneuver How do spacecraft maneuver in the absence of air?in the absence of air?

Newton’s 3rd LawNewton’s 3rd Law High Pressure Fuel Exerts a force on one side High Pressure Fuel Exerts a force on one side

of rocket while being released out the back.of rocket while being released out the back.

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