Water and Air Pressure. Pressure. The amount of force applied to a given area. Why do ears ‘pop’? Answer: When the air pressure outside changes, the air pressure inside your middle ear has to adjust, resulting in the popping sound. Air Pressure. - PowerPoint PPT Presentation
Text of Water and Air Pressure
Water and Air Pressure
The amount of force applied to a given area.
Why do ears ‘pop’?
Answer: When the air pressure outside changes, the air pressure inside your middle ear has to adjust, resulting in the popping sound..
Air PressureAir Pressure
is a measure of the force of the air pressing down on the earth’s surface
Air Pressure can vary at any can vary at any particular point on the Earth particular point on the Earth depending on the density of the airdepending on the density of the air
Density = mass / volumeDensity = mass / volume
Changes in Pressure
Layers of air in the Earth’s atmosphere are higher than 160 km above the Earth’s surface.
Being closer to the surface, we experience air pressure as a result of all the air particles being pulled toward the Earth by gravity.
Changes in Air Pressure
You experience less air pressure as you travel to higher altitudes because of the fewer layers above us and air is less dense.
DensityDensity = Mass / Volume Warm air is less dense than cool air. Warm air rises. Cool air sinks.
Air at high altitudes is less
dense than air at lower altitudes.
Pressure in Depth-Water Pressure
The weight of the water at the upper part of the pool presses down on the deeper levels of the pool, resulting in greater pressure at that point.
(Hence, your ears feel a lot of pressure deeper in the waters)
Pressure does not include the total amount of fluid present only the depth of the fluid.
Water is about 1000 times more dense than air.
If you measure the same volume of water and air, water has more mass and weighs more than air.
Water exerts a greater pressure than air pressure.
Pressure and Fluid Flow
Fluid will always want to move from an area of high pressure to an area of low pressure
When drinking a juice box, the straw pulls from an area of high pressure (juice box) to an area of lower pressure (mouth)
Pressure and Temperature
When temperature increases, particles more faster and strike the walls of their container more often and with more force
When enough force is exerted and the volume of the container cannot increase anymore an explosion can occur
Compression is a decrease in volume caused by a force
Gasses can experience compressibility because the particles in a gas are so far apart that they have room to move closer to one another
Materials in a liquid state are incompressible
Compressibility is the ability to be compressed, or forced to have less volume
Gas can be compressed We pushed the particles closer together through force and
reducing the volume of the bottleWhen enough force is exerted and the volume of the
container cannot increase anymore an explosion can occurWater vapour (gas) is in airWater was inside the bottle and when the bottle opened
pressure was released and returned to its gaseous form (i.e. what looked like smoke coming out of the bottle)
Results and Explanation:
1. Fill a cup with water. 2. Cover the cup with an index card.
3. Invert the cup. What happened?
Does the water spill out of the cup? Explain (using concepts on pressure)
Title: Activity 1. Inverted Cup Date: Feb. 2010
Inverted CupInverted Cup
When cup is completely filled with water, no air is
left in cup, thus no air pressure. The inverted cup can therefore hold
water up because the air pressure is working
against the underside of the cup.
There is higher air pressure outside pushing There is higher air pressure outside pushing upward than the inside of cup pushing downwardupward than the inside of cup pushing downward..