| A | B |
|---|
| WEATHER | The condition of Earth's atmosphere at a particular time and place. (Rain, Snow) |
| OZONE | Form of oxygen that has 3 oxygen atoms in each molecule instead of 2. |
| ATOMOSPHERE | Layer of gases that surrounds Earth. |
| WATER VAPOR | Water in the form of gas. |
| PHOTOCHEMICAL SMOG | Brownish haze that is a mixture of ozone and other chemicals formed when nitrogen oxide, hydrocarbons, and other pollutants react with each other in the presene of SUNLIGHT. |
| ACID RAIN | Rain that contains more acid than normal. |
| DENSITY | Amount of MASS of a substance to a given volume. |
| PRESSURE | Force pushing on an area or surface. |
| AIR PRESSURE | Force that is the result of the weight of a column of AIR pushing down on an area. |
| BAROMETER | Instrument used to measure the changes in air pressure. |
| MERCURY BAROMETER | Instrument that measures change in air pressure consisting of a glass tube 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 higher in the tube. |
| ANEROID BAROMETER | Instrument that measures changes in air pressure WITHOUT using a liquid. Changes in the shape of an airtight metal box cause a needle o nthe device's dial to move. |
| ALTITUDE | Elevation above sea level. |
| TROPOSHPHERE | Lowest layer of Earth's atmosphere, where weather occurs. |
| STRATOSPHERE | Second-lowest layer of Earth's atmosphere; OZONE layer is located in the upper part of this layer. |
| MESOSPHERE | Midde layer of Earth's atmosphere; Layer in which most METEOROIDS burn up. |
| THERMOSPHERE | Outermost layer of Earth's atmosphere. |
| IONOSPHERE | Lower part of the thermosphere where electrically charged particles called IONS are found. |
| AURORA BOREALIS | Colorful glowing display in the sky caused when particles from the sun strike oxygen and nitrogen atoms in the IONOSPHERE. Also called NORTHERN LIGHTS. |
| EXOSPHERE | Outer layer of the thermosphere extending outward into space. |
