Chapter 10 Atmosphere and Air Pressure Atmosphere and

Chapter 10 Atmosphere and Air Pressure

Atmosphere and Air Pressure • The sun provides heat and energy for the Earth. • The angle at which sunlight strikes Earth’s surface is called the angle of insolation.

Seasons • Seasons are caused by • The tilt of the Earth on its axis • The revolution of the Earth around the sun • The angle of the sun’s rays

Why do some things get hotter than others? • Dark colors absorb more heat. • Light colors reflect more heat. • Rough textures cause light to bounce around at many angles absorbing more energy. • Rough surfaces get hotter than smooth surfaces. • Land absorbs more heat or energy than water.

What is the Atmosphere? • Atmosphere is the air that surrounds the Earth. It reaches from the Earth’s surface to the edge of space.

Layers of the Atmosphere • The troposphere is the layer closest to the Earth’s surface. It is the narrowest layer (8 km to 18 km thick). It contains most of the air in the atmosphere. • All life exists in the troposphere. • All weather occurs in the troposphere.

Layers of the Atmosphere • The layer above the troposphere is the stratosphere. It is between 18 km to 50 km. • The layer above the stratosphere is the Mesosphere. It is between 50 km to 80 km. • The layer above the Mesosphere is thermosphere. It is above 80 km high.

How does air pressure change with altitude? • Air is a mixture of gases. It is mostly made up of molecules of nitrogen and oxygen. • Molecules are the smallest pieces that a substance can be broken into without changing what the substance is. They have mass, so they have weight. • Air pressure is the force put on a given area by the weight of the air above it. • As you go higher in altitude, air pressure steadily decreases.

What is Weather? • Weather is what the lower atmosphere, or troposphere is like at any given place and time. • The conditions that make up weather are air temperature, air pressure, amount of moisture in the air, wind, clouds, and rain or snow.

Measuring Weather • You can measure temperature with a thermometer. • Thermometers can use two different temperature scales. The Celsius scale is marked with the letter C. • The Fahrenheit scale is shown by the letter F.

Measuring Air Pressure • Air pressure is measured with a barometer. • Two common types of barometers are the mercury barometer and the aneroid barometer. • In a mercury barometer, air pressure pushes mercury up in a tube. • A spring inside an accordion-like metal can measures air pressure in an aneroid barometer. *** Read pages D 30 – D 35 ***