Thursday, November 20, 2008

Kelvin and gases

Kelvin is used in measuring the temperature of gases because it is an absolute value. This way the temperature will never be below zero.

More about Gases

More Temperature=Less Pressure
More Temperature=More Volume
More Volume=Less Pressure


Boyles' Law- Explains the inverse relationship betweeen pressure and volume.
Video...



Charles' Law- At constant pressure, the volume of a mass increases at the same interval as temperature. Here is an example.



Bernoulli's Principle

Bernoulli's Principle states that an increase in the speed of a fluid is always joined by a decrease in pressure. Planes can fly because their wings are designed so that the air above the wings must travel a longer distance in the same amount of time so it travels faster. The air below the wing doesn't have to travel as far so it goes slower. The plane can then float on the higher pressure airbelow the wing and the air above with it's lower pressure will allow the plane to go upwards.

This picture shows the shape of the wings of a plane

Gases

Some Physical Properties of Gases:
-Indefinite volume
-Indefinite shape
-Very high temperature
-Very high energy
-Very low energy
-Gases are compressible

Some Examples:
-Oxygen


-Car exhaust

Floating

For an object to float its weight must be less than the bouyant force. The bouyant force is the amount with which the water exerts an upward force. Archimedes Principle is further explaining this because it states that the buoyant force on an object in a fluid is equal to the weight of the liquid that the object displaces.

Wednesday, November 19, 2008

Strengths

Strength- the ablity if a solid to maintain shape even when a force is applied.
Stress- the ratio of the force acting on a material divided by the cross section area through which the force is carried
Tensile Strength- the measure of how much thrust in pulling, or tension, a material can withstand before breaking
Elasticity- the ability of a solid to be streched and return to its original position
Brittleness- the tendancy of a solid to crack or break when a force is applied
Bending- curving of an object to create tension and compression

Tuesday, November 18, 2008

Liquids

Some physical properties of Liquids:
-Definite volume
-Takes shape of container
-More energy than solids
-Lower density than solids (still fairly high) this is because...
-Particles are farther apart than those in solids (aka- packed loosely)\

-Particles have the ability to flow



Some examples of Liquids:
-Water
-Mercury
-Lava