| A | B |
|---|
| The atmosphere is... | the layer of gases that surround Earth |
| Earth's atmosphere is important to living things because it | provides all the gases needed |
| Earth's atmosphere traps energy from the sun, which | allows water to exist as a liquid |
| The two most abundant gases in the atmosphere are | nitrogen and oxygen |
| Earth's atmosphere contains about 4 times as much nitrogen as | oxygen |
| The gases in our atmosphere aside from oxygen and nitrogen make up about what percentage of dry air? | 1% |
| Ozone is | a form of oxygen with three oxygen atoms |
| Water vapor is water in the form of | a gas |
| In addition to gases, air also contains | particles |
| What is the thick, brownish haze formed when certain gases react in sunlight? | photochemical smog |
| Is a common indoor air pollutant | cigarette smoke |
| Which indoor air pollutant is a colorless, odorless gas that forms when wood, coal, oil, or gas are incompletely burned? | carbon monoxide |
| What is the major source of photochemical smog? | gases emitted by automobiles and trucks |
| What is the major chemical found in smog? | ozone |
| The ozone layer protects people from which of the following? | too much ultraviolet radiation |
| One group of gases that is responsible for destroying ozone in the ozone layer is | ChloroFluroCarbons (CFCs) |
| The ozone layer is located | in the upper atmosphere |
| Heat trapped near Earth's surface by | the greenhouse effect |
| Increased amounts of carbon dioxide in Earth's atmosphere may lead to | global warming |
| Which gas increases the greenhouse effect | carbon dioxide |
| Most scientists base their climate predictions on | computer models |
| Density can be determined using | Density=mass/volume |
| The less mass in a given volume of air, the | less dense the air |
| Air in the atmosphere has pressure because | air has mass |
| The air pressure acting on the roof of your house | comes from the air above and below your roof |
| The National Weather Service measures air pressure in units called | millibars |
| Instruments used to measure air pressure are called | barometers |
| An aneroid barometer is different from a mercury barometer in that it | does not contain a liquid |
| When climbing a high mountain, you get out of breath easily because | there is less oxygen in each cubic meter of air |
| The main layers of the atmosphere are classified according to changes in | temperature |
| The layer in our atmosphere in which weather occurs is the | troposphere |
| From Earth to space, the main layers in our atmosphere are | troposphere, stratosphere, mesosphere, thermosphere |
| The ozone layer in the stratosphere absorbs | ultraviolet radiation |
| What is the first layer of atmosphere an astronaut passes through during reentry from space? | exosphere |
| Radio waves are reflected back to Earth in the | ionosphere |
