| A | B |
|---|
| weather | is the condition of Earth’s atmosphere at a particular time and place. |
| atmosphere | s the layer of gases that surrounds the planet. |
| The atmosphere consists of | nitrogen, oxygen, carbon dioxide, water vapor, and many other gases, as well as particles of liquids and solids. |
| ozone | is a form of oxygen that has three oxygen atoms in each molecule instead of the usual two. |
| water vapor | is water in the form of a gas (and is invisible). |
| air pollution | A change to the atmosphere that has harmful effects |
| emissions | Solid particles and gases that are released into the air. |
| photochemical smog | a thick, brownish haze formed when certain gases in the air react with sunlight. |
| ozone | A toxic form of oxygen. |
| temperature inversion | Condition in which a layer of warm air traps polluted air close to Earth’s surface. |
| acid rain | Precipitation that is more acidic than normal. |
| ozone layer | The layer of the atmosphere that contains a higher concentration of ozone than the rest of the atmosphere. |
| How does the ozone layer help us? | It protects people from the effects of too much ultraviolet radiation. |
| chlorofluorocarbons | Gases containing chlorine and fluorine (also called CFCs). |
| greenhouse effect | The trapping of heat by certain gases in the atmosphere. |
| global warming | The theory that increasing carbon dioxide in the atmosphere will raise Earth’s average temperature. |
| density | The amount of mass in a given space; mass per unit volume. |
| pressure | The amount of force pushing on a surface or area. |
| air pressure | A force that is the result of the weight of a column of air pushing down on an area. |
| barometer | An instrument used to measure changes in air pressure. There are two types of this instument:mercury and aneroid. |
| mercury barometer | An instrument that measures changes in air pressure, consisting of a glass tube part filled with mercury, with its open end resting in a dish of mercury. Air pressure pushing on the mercury in the dish forces the mercury in the tube higher |
| aneroid barometer | An instrument that measures changes in air pressure without using a liquid. Changes in the shape of an airtight metal box cause a needle on the barometer dial to move. |
| altitude | Elevation above sea level. |
| What is the rule abour air pressure? | Air pressure decreases as altitude increases. As air pressure decreases, so does density. |
| How are the layers of the atmosphere classified? | The four main layers of the atmosphere are classified according to changes in temperature. These layers are the troposphere, the stratosphere, the mesosphere, and the thermosphere. |
| tropesphere | The lowest layer of Earth’s atmosphere, where weather occur |
| stratosphere | The second-lowest layer of Earth’s atmosphere; the ozone layer is located in the upper stratosphere. |
| mesophere | The middle layer of Earth’s atmosphere; the layer in which most meteoroids burn up. |
| thermosphere | The outermost layer of Earth’s atmosphere. |
| ionosphere | The lower part of the thermosphere, where electrically charged particles called ions are found. |
| aurora borealis | A colorful, glowing display in the sky caused when particles from the sun strike oxygen and nitrogen atoms in the ionosphere; also called the Northern Lights. |
| exosphere | The outer layer of the thermosphere, extending outward into space |
