Earth's Atmosphere Flashcards
Which gas exists in Earth’s atmosphere in the largest percentage?
Nitrogen (78%)
Which gas makes up about 21% of Earth’s atmosphere?
Oxygen
Which gas is not included in the percentages of Dry Air in the atmosphere?
Water Vapor. The amount varies by location and from day to day. The other gases are more consistent.
How is nitrogen gas from the atmosphere converted to usable forms?
Nitrogen fixing bacteria convert atmospheric nitrogen to nitrogen compounds that plants can absorb through their roots.
How is nitrogen important to living organisms?
Nitrogen is an important element in the formation of proteins.
What are the two forms of oxygen in the atmosphere?
Diatomic oxygen and triatomic ozone.
What are two uses for diatomic oxygen?
It is used by animals in cellular respiration, and it is needed for the chemical reaction of combustion.
What are two forms of combustion?
Burning is an example of rapid combustion, while rusting is an example of slow combustion.
How does ozone protect organisms?
The ozone layer prevents most of the UV radiation from the Sun from reaching Earth’s surface.
What are two benefits of carbon dioxide in the atmosphere?
Carbon dioxide is a greenhouse gas that helps keep the Earth at a temperature for living organisms to exist. Carbon dioxide is also used by plants during photosynthesis.
What is the source of water vapor in the atmosphere?
Evaporation from surface water and transpiration from plants.
What are some forms of water in the atmosphere?
Water can be an invisible gas in the form of water vapor. Small water droplets can form clouds. Small ice crystals can also form clouds. Precipitation leaves the atmosphere and falls to Earth’s surface.
Why is water vapor in the atmosphere important?
It is the source of freshwater when it falls to Earth’s surface. Organisms need fresh water to survive.
What causes air pressure?
The column of gases pressing down on an area.
How does air pressure change with altitude?
As altitude increases, the air pressure decreases. This is because the column of air is smaller and the density of air is less.
What are the two types of barometers?
Aneroid barometer and mercury barometer.
What does a barometer measure?
Air pressure
What are two common units for air pressure?
Inches of mercury and millibars.
How is pressure calculated?
Pressure is force divide by area.
How is area calculated?
Area is length X width
Which layer of the Atmosphere is closest to Earth’s surface?
The troposphere
In which layer of the Earth contains 75% to 90% of all gases?
The troposphere
Why is weather mostly found in the troposphere?
The layer closest to Earth’s surface will have water entering and leaving it.
Why are most of the gases in the atmosphere located in the troposphere?
This layer is closest to Earth’s surface, so gravity force is stronger and the column of air pressing down is larger.