Atmospheric Science - 9th Grade

What percentage of Earth's atmosphere is nitrogen?

78%

What percentage of Earth's atmosphere is oxygen?

20.95%

What is atmospheric pressure at sea level (in mmHg)?

760 mmHg

What is air pressure per square inch at sea level?

Nearly 15 pounds per square inch

How do you calculate partial pressure?

Multiply total atmospheric pressure by the decimal percentage of that component (Example: Nitrogen = 760 mmHg x 0.78084)

How does atmospheric pressure change with altitude?

Atmospheric pressure decreases as altitude increases due to less air column above

What is the troposphere?

The lowest layer of the atmosphere, next to Earth's surface and home to most weather

What is the stratosphere?

The layer above the troposphere, home of the ozone layer

What is the mesosphere?

The middle layer where meteorites often burn up due to denser air

What is the thermosphere?

The uppermost atmospheric layer which gets very hot

What is the ionosphere?

A sublayer in the thermosphere where auroras (Northern and Southern Lights) occur due to solar ionization

What is the exosphere?

The layer beyond the thermosphere

What is partial pressure of nitrogen at sea level?

593.4 mmHg

What is partial pressure of oxygen at sea level?

159.22 mmHg

How high does the column of air extend that creates atmospheric pressure?

About 700 km

What causes the Aurora Borealis and Aurora Australis?

Solar energy causing ionization in the ionosphere

What determines how the layers of the atmosphere are defined?

They are defined by temperature, though density changes with altitude (becoming less dense higher up)

What percentage of the atmosphere is composed of gases other than nitrogen and oxygen, plus water vapor and dust?

About 1%

What creates global winds?

Solar energy leading to convection cells

What happens to meteors in the mesosphere?

They usually burn up due to friction

What is ozone?

Oxygen changed from O2 to O3

Why is the ozone layer crucial?

It absorbs potentially harmful UV radiation, making life possible on Earth's surface

Why doesn't the thermosphere feel hot despite high temperatures?

The atmosphere is so thin that not much heat is released

What happens to particles in the ionosphere?

They become electrically charged (ions) by absorbing energy, stopping it in the upper atmosphere

What acts like a shield in space to protect Earth?

Earth's magnetic field (and the Sun's magnetic field further away)

What are the main ways Earth is protected from dangerous solar energy?

Ionosphere absorbs some energy, atmosphere burns up solids, and ozone absorbs UV energy

What is the source of all energy in the atmosphere?

The Sun

What are the three ways energy is transferred to Earth and throughout the atmosphere?

Radiation, conduction, and convection

What is the greenhouse effect?

The heating of the lower atmosphere from radiation absorbed by heat-absorbing gases

Why is the greenhouse effect important for life?

Without it, Earth would not be habitable - it allows life to flourish by trapping heat

How does the greenhouse effect work?

The atmosphere traps thermal (heat) energy and reflects it back to Earth

What do scientists think about increased greenhouse gases?

They may be part of the cause of global temperature changes and accelerating those changes

What role do the atmosphere's layers play in protection?

All layers provide protection through particles present, friction, absorbing energy, and other mechanisms

What gas is of particular concern for increasing the greenhouse effect?

Carbon dioxide

What are the three main ways the atmosphere protects us?

1) Ions stopped in thermosphere, 2) Objects burn up in atmosphere, 3) Ozone blocks UV radiation

Why can the magnetic field protect Earth in ways the atmosphere cannot?

Because it affects charged particles, while the atmosphere is relatively inert

What generates Earth's magnetic field?

Heat making the outer core convect

What makes magnetic fields in general?

They are made wherever there is an electric current (movement of electrons)

How thick is Earth's liquid outer core?

2270 km

What is the diameter of Earth's solid inner core?

2400 km

What are both cores made of?

Iron and nickel

How fast does molten iron flow in Earth's core?

About 0.8 inches per second

How strong is Earth's magnetic field in Gauss?

0.4 Gauss, weaker than a small hand-held magnet

How far does Earth's magnetic field extend into space?

7-10 times Earth's diameter

What shape is Earth's magnetic field and why?

Tadpole-shaped because solar wind compresses it on the sun-facing side and stretches it into a tail on the opposite side

What is the solar wind?

Extremely hot, high-energy, fast-moving charged particles (mainly protons with positive charge) given off by the sun

What would happen without Earth's magnetic field?

All life would die as the magnetic field is needed to channel away solar wind and block dangerous radiation

What percentage of the Sun's energy reaches Earth?

Less than 1%

What else does the magnetic field prevent besides radiation damage?

Prevents erosion of the atmosphere by the solar wind

What can happen to Earth's magnetic poles?

They can reverse or "flip" for unknown reasons

What unique ability do some animals have regarding Earth's magnetic field?

They can sense it and use it for navigation

How is Earth's core magnetic field generated differently from a bar magnet?

Bar magnets generate fields from electrons orbiting iron atom nuclei all in the same direction, while Earth's field comes from electrical currents in the molten iron core

What are the three ways energy is transferred in the atmosphere?

Radiation, conduction, and convection

What is radiation?

The transfer of energy as electromagnetic waves

What is thermal conduction?

The transfer of thermal energy through a material

What is the greenhouse effect?

The process by which gases in the atmosphere absorb thermal (heat) energy and radiate it back to Earth

What wavelength energy passes easily through the atmosphere?

Short wavelength energy

What wavelength energy has difficulty escaping the atmosphere?

Long wavelength energy

What percentage of greenhouse gases is made up of the top five gases?

98%

What is the most abundant greenhouse gas and its percentage?

Carbon dioxide at 56%

What is the second most abundant greenhouse gas and its percentage?

Methane at 16%

What percentage of greenhouse gases are CFCs and what is their origin?

13%, and they are man-made

What percentage of greenhouse gases is ozone?

7%

What percentage of greenhouse gases is nitrous oxide?

6%

What is needed for Earth to be livable regarding energy balance?

The amount of energy Earth receives must be approximately equal to the amount of energy returned to space

How much of the Sun's total energy output reaches Earth?

A fraction of a percent

List the five main greenhouse gases in order of abundance

Carbon dioxide (56%), Methane (16%), Chlorofluorocarbons (13%), Ozone (7%), Nitrous oxide (6%)

What is the main human contribution to nitrous oxide?

Agriculture and fossil fuel use

What is the main source of methane?

Natural production through fermentation and animals

Why is ozone listed as a greenhouse gas when it's protective?

It's naturally produced but some is created by reactions with human pollution

What is the Coriolis effect?

The apparent curving of the path of currents due to the Earth's rotation

What are Polar Easterlies?

Wind belts that extend from the poles to 60° latitude in both hemispheres

What are Westerlies?

Wind belts found between 30° and 60° latitude in both hemispheres

What are Trade Winds?

Winds that blow from 30° latitude almost to the equator in both hemispheres

What are the Doldrums?

Area around the equator where the trade winds of the Northern and Southern Hemispheres meet

What are the Horse Latitudes?

Areas of high pressure at about 30° north and 30° south latitude created by sinking air

What are Jet Streams?

Narrow belts of high-speed winds in the upper troposphere and lower stratosphere that can reach speeds of 400 km/hr

What is the maximum speed of Jet Streams?

400 km/hr (250 mph)

How do Jet Streams flow in North America?

From west to east

What are two uses of Jet Streams?

Pilots use them to cut arrival times and meteorologists use them to track storms

What causes mountain and valley breezes?

They are local winds caused by an area's geography

What causes sea and land breezes?

Pressure differences throughout the day affected by sunlight and changes in surface temperature

How are pressure belts organized globally?

They are found every 30° and separate convection cells

Why does air rise at the equator and sink at the poles?

As cold air sinks at poles, it creates areas of high pressure, causing the cold polar air to flow toward the equator

How is wind direction named?

Wind is named for where it comes FROM

Why does water temperature change more slowly than land?

Due to its high specific heat

What are the characteristics of local winds?

They generally move short distances and can blow from any direction

How do global winds affect Earth?

They control ocean currents

What is the water cycle?

The continuous movement of water from Earth's surface into the air, onto and over land, into the ground, and back to the surface

What is humidity?

The amount of water vapor in the air

What is relative humidity?

The amount of water vapor in the air compared to the maximum amount of water vapor that the air can hold at a certain temperature

What is the formula for relative humidity?

[actual water vapor content/saturation water vapor content] × 100

What is a psychrometer?

An instrument with two thermometers (one wet-bulb) used to measure relative humidity

What is condensation?

The process by which a gas, such as water vapor, becomes a liquid

What is dew point?

The temperature at which a gas condenses into a liquid

What instrument measures precipitation?

Rain gauge

What instrument measures wind speed?

Anemometer

What instrument measures wind direction?

Wind vane

What instrument measures air pressure?

Barometer

What are cloud condensation nuclei (CCNs)?

Small particles about 1/100th the size of a cloud droplet about which cloud droplets condense