8th Grade Science Final Flashcards
Layers of the atmosphere
- Troposphere (closest to earth)
- Stratosphere
- Mesosphere
- Thermosphere
- Exosphere (furthest from earth)
Air Pressure
Because our atmosphere is made up of gases, which have mass, we feel the force of these molecules pushing down on us at the surface of Earth. The molecules of air are more densely packed here because of that force. We are at the bottom of an ocean of air.
Atmospheric pressure changes with altitude; the more air you have above you the more pressure you will feel. Therefore, the higher you go the less pressure you feel, because earth’s atmosphere is below rather than above you.
On average a column of air one square inch in cross section measured from sea level to the top of the atmosphere has a mass of 14.7 pounds. This would be equivalent to being under 34 feet of water.
High pressure is usually associated with…
good weather
Low pressure is usually associated with…
bad weather
Jet streams
Occurs in the upper levels of our troposphere.
A channel of fast-moving air.
Creates a boundary between different air masses.
What is the greenhouse effect?
A process that happens when Carbon Dioxide is trapped in Earth’s atmosphere (creates heat)
Is the Greenhouse Effect a good or bad thing?
It is a good thing because it helps to keep earth warm and alive. It is also bad when there is too much Carbon Dioxide in the atmosphere and it heats earth too quickly.
The greenhouse effect: how have humans impacted?
Human emissions impact greatly and can become harmful.
The water cycle
the movement of water between the earth and the atmosphere
precipitation
the product of condensation in the atmosphere that falls due to gravity
condensation
the process of water vapor changing from gas to liquid.
transportation
the process by which plants release extra water vapor by evaporation through their leaves.
evaporation
the process where liquid changes to a gas
2 main gases that make up the troposphere and their %
78% nitrogen
21% oxygen
What happens to the sun’s radiation when it hits the atmosphere? (4 things)
- absorbed by the atmosphere
- absorbed by the earth’s surface
- reflected by the atmosphere
- reflected by earth’s surface
where is the ozone layer located?
stratosphere (second layer)
chemical formula of the ozone layer
O3
Why is the ozone layer important to life on earth?
Ozone absorbs 97-99% of the sun’s high frequency ultraviolet radiation (uv) which is damaging to life on earth.
What caused a hole in the ozone layer to form?
Some of the chemicals that are emitted by manmade pollutants, CFS’s, are thought to be responsible for breaking down the ozone layer.
High and low pressure
H and L
Cold front
blue triangles
warm front
red circles
stationary front
red circles and blue triangles
isobars
connect points of equal pressure on a weather map.
isotherms
connect points of temperature (usually color coded)
What is a front?
a weather system that is the boundary separating two different types of air.
What usually happens at fronts?
When two different air types interact, we get turbulence which creates storms
Hurricane
a large, swirling, low pressure system that forms over tropical oceans
Sea breeze vs. Land breeze
During the day, the land is warmer, and the ocean is cooler. During night, the land is cooler, and the ocean is warmer.
Weather watch
DOES NOT GURANTEE SOMETHING IS GOING TO HAPPEN. Just describes what is likely to happen.
Weather warning
a storm exists, this is where it is, this is where it is going. LOOK OUT!
Relative humidity
- The “closeness the air is the saturation”
- RH < 40% = feels dry
- RH> 80% = feels moist (humid
- Between 40-80% RH feels comfortable if the temperature is also comfortable.
- It is important to remember that as the temperature increases, the atmosphere has the ability to hold MORE water vapor. The opposite is also true.
Rain Shadow Effect
- As air approaches a mountain, it is forced upward
- Since atmospheric temperatures drop as elevation increases, the water vapor in this air cools and condenses causing precipitation.
- By the time the air reaches the other side of the mountains, all of the moisture is gone, and it becomes very arid. (dry)
Hail
- Always associated with large, powerful thunderstorms
- Summertime event
Sleet
- Winter event
- Sleet is a frozen rain drop
Freezing Rain
- As the liquid water hits the surface, it freezes
- The ground must be frozen
- Winter event
What is climate?
the average weather in a certain area over long periods of time.
How does climate differ from weather?
- Weather is the current conditions of the atmosphere. Climate is the AVERAGE OVER LONG PERIODS OF TIME
5 main factors that influence climate for a particular area.
- Cities
- Latitude
- Large Bodies of Water
- Ocean Currents
- Mountains
Cities
Create a MICROCLIMATE.
Have warmer than average temperatures for 2 reasons.
(1) the materials of a city (concrete, buildings, roads, parking lots) absorb heat and hold heat throughout the day/night.
(2) Pollution of a city increases the greenhouse effect in city and surrounding areas.
Latitude
Since earth is a sphere, the angle at which the sun strikes the surface varies as you move north or south of the equator.
The steepness of this angle influences the intensity of the sun’s energy.
Large bodies of water
Have a moderating effect on climate
Near large bodies of water, winters will be more mild, summers will be cooler
Large bodies of water can also increase the chance of precipitation.
Mountains
Rain shadow effect (see notes)
As elevation increases, average temperature decreases
What are the three main climate zones on earth?
Polar, temperate, and tropic
Polar regions
- sun’s energy arrives at an oblique angle.
- Least amount of sunlight and are therefore frigid
- Ice and snow also reflects a large part of what little sunlight the Polar regions receive
Temperate
- Between the tropics and the polar regions.
- The temperatures in these regions are generally relatively moderate
- Most temperate climates have 4 seasons
- Most of the world’s population lives in the temperate zone.
Tropic zone
- Warm to hot and moist year-round
- Lush vegetation
- Receives the most direct solar radiation
- Only 2 season, WET AND DRY
