Can you feel air pressure?

Air pressure depends on the density of the air, or how close together its molecules are. Air lower in the atmosphere is more dense than air above, so air pressure down low is greater than air pressure higher up. As we know, the air in the atmosphere is made up of a number of gases. These gases press down on the Earth’s surface, exerting a force that we call air pressure. Although we are usually unaware of this pressure, it actually presses down very hard – roughly equivalent to the force of an elephant balancing on a desk!

There is a “blanket” of air around the Earth called the atmosphere and this results in what we call air pressure. How can we prove that the air has weight?

The air in the atmosphere is kept close to the Earth by the pull of gravity, the force that pulls everything-including you and I- down to the ground. Withouo gravity we would be weightless and would float above the ground.

ATMOSPHERE:Is a layer of gases surrounding the Earth that is retained by earth`s gravity.

What causes air pressure?

Air pressure depends on the density of the air, or how close together its molecules are. Air lower in the atmosphere is more dense than air above, so air prssure down low is greater than air pressure higher up. Temperaure also males changes in air pressure. In cold air, the molecules are more closely packed together than in warm air, so cold air is more dense than warm air.

Rising and Sinking Air

Since

Since warm air is less dense and creates less air pressure, it will rise; cold air is denser and creates greater air pressure, and so it will sink. When warm air rises, cooler air will often move in to replace it, so wind often moes from areas where it´s colder to areas where it´s warmer.

WIND DIRECTION Wind blows from areas of high pressure to

areas of low pressure but it doesn´t blow in a straight line. That´s because the earth is rotating. In the northern hemisphere, th spin of the earth causes winds to curve to the right and to the left in the southern hemisphere, this is called CORIOLIS EFFECT.

CORIOLIS EFFECT

The main cause of the Coriolis effect is the earth´s rotation. The coriolis effect also affects the movement of the ocean´s currents.

Humidity and Precipitation

Humidity is the amount of water vapor contained in the atmosphere. Precipitation, is all forms of water that fall from the atmosphere into the earth´s surface. Timing and volume of precicpitation are important aspects of climate.

ACTIVITIY: On the world map represent with red and blue colors the warm and cool currents.

1. -What are the five oceans on Earth? 2. What are the seven continents on Earth? 3. Color the oceans and seas blue. 4. Color the continents green. 5. Draw a red line along the equator6. P. 67 Ocean currents (blue and red)

ATMOSPHERE:Is a layer of gases surrounding the Earth that is retained by earth`s gravity.

CONVECTION: Helps to make the Earth liveable by removing excess heat from the surface.

Convection plays a huge role in our environment around us. Earthquakes and volcanoes are caused by massive convection currents in the molten magma under the Earth´s crust.

CONVECTION CURRENTSThe mantle is made of much denser,

thicker material so the plates “float” on it like oil floats in water. CC are caused by the very hot material at the deepest part of the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over.

When the convection currents flow in the mantle they also move the crust. Convection currents in the mantle move plats of the Earth.

CURRENTS

The water of the oceans also help to distribute heat. Following convection patters similar to those of winds. Carries warm watr from the tropics to the poles. Other currents return cold water to the Equator.