Flight and Air

Bernoulli's Principle

Bernoulli's Principle states that rushing air creates low pressure and still air creates high pressure. This applies to an airplane wing because it is in a airfoil shape. A airfoil shape is curved on top making it longer than the bottom which is straight. Since the top is longer, the air has to move faster on top and slower on bottom. The slow moving air on bottom creates high pressure that lifts the wing up achieving lift!

Parachutes

A parachute is a very simple floater that works like this:

A parachute has a large canopy that has a small hole in the top called the air hole, the air hole is used to stabilize the parachute and control how fast the parachute descends. Although the hole in the top can control how fast the parachute descends,  doesn't mean that it’s the only variable that can change the speed. The speed can also change depending on how much weight is attached to the canopy using the shroud lines, the more weight the faster the descent.

The Five Properties of Air

The five properties of air are:

1. Air has mass.

2. Air exerts pressure.

3. Air occupies space.

4. Air can be compressed.

5. Air can flow around surfaces.

Archimedes Principle

This video is all about Archimedes Principle! Enjoy!

Composition of Air

Fire uses oxygen so, if you put a candle under glass there is limited oxygen. This means that the candle will burn out. Another thing is that if you stand up a candle in any liquid, then you light the candle and, put a glass over it the liquid will rise. This is because the candle is using up oxygen which is part of the air. This means that there is less air in the jar so, more room for the liquid, causing the liquid to rise in the jar.

Propellers

The propeller is the planes way of creating thrust. Or in a helicopters case, it's lift. These propellers are basically a mini airplane wing. On an airplane they are on the nose and, the are veritcal in a circle shape. On a helicopter they are on the fuselage horizontally placed in a circle.

The Four Forces of Flight

The four main forces of flight are lift, thrust, gravity, and drag.

In order to achieve flight, lift and thrust must be greater

than the opposite forces, drag and gravity. Thrust is 

produced by the propellers, and lift is produced by the wing.

Adaptations of a Bird

Streamlined body------->  Helps make the bird more aerodynamic so it can fly easier and faster.  

Tucks feet in when flying---------->   Helps streamline by reducing drag.

Hollow bones-----------> helps reduce the bird’s body weight so the lift can overcome it.

Comparison of Birds and, Airplanes

BIRDS	PLANES
streamlined body	streamlined fuselage
airfoil shaped wings	airfoil wings made of metal
birds tuck their feet in during flight	planes retract their wheels during flight
they get the lift from their wings	planes get their lift from their wings
their wings are as long as their body	the wings are as long as the body of the plane's body

Adaptations of a Swimmer

In swimming, most of the things we can change will involve reducing drag, this is because in swimming, your goal is to go fast and drag slows you down.

Shave hair---------> This will reduce the drag that the hair would cause.

Small goggles-------> This will reduce the drag because big goggles will produce drag.

Tight bathing suit--------->  This will cling to the swimmer whereas a baggy bathing suit will create drag.

Hot Air Balloons

On a hot air balloon there are three main parts; the shroud lines, the basket and, the envelope. Their lift is achieved by the hot air blown into the envelope by the burner. The hot air rises into the air and, a big part in the lift of a hot air balloon is Archimedes Principle. this is when the other parts of the hot air balloon come in. The balloon rises which is connected by the shroud lines to the basket which the passengers are held in. There is also, a hole at the top of the balloon which can be opened and, closed causing the balloon to rise or, fall.

The Parts of an Airplane

Parts of Airplane	What it does
ailerons	controls the roll
cockpit	hold the controls
flaps	slow the plane down when landing by increasing drag
elevators	controls pitch
horizontal stabilizer	stabilizes the airplane
vertical stabilizer	stabilizes the airplane
rudder	controls banking
fuselage	body of the plane
wings	create lift
propellers	create thrust

Spacecraft

Designing spacecrafts is a big challenge for mechanics because there is no air in space, meaning bernoulli's principle does not apply. Spacecrafts are made to go really fast and break through the atmosphere, they then orbit around the Earth.

Floaters, Gliders and, Powered Gliders

Floaters	Gliders	Powered gliders
Need wind to be moved.	Travel from a high point to a low point.	Creates and maintains their own thrust.
Can not control their own direction.	Glides, and slowly descends through the air.	ex. airplane, birds
ex. seeds, balloons	ex.paper airplane, wing suit