Earth’s Atmosphere Flashcards
What is the atmosphere?
The layer of gasses that surrounds the earth, providing us with the air we breath and helping to regulate temperature and weather patterns.
Whys the atmosphere important?
• it contains oxygen that living beings need to breath
• protects against meteorites
• shields against radiation and cosmic rays
• maintains earths temperatures
What is the atmosphere made of?
A thin layer of gases surrounding earth; made up of nitrogen, oxygen, carbon dioxide, water vapour, and other gases (trace gases such as Ne, He, CH4, H2, Kr), as well as particles of liquids and solids.
What are the percentages of nitrogen, oxygen, argon, and CO2 in our atmosphere?
Nitrogen = 78%
Oxygen = 20.9%
Argon = 0.9%
CO2 = 0.02%
Why is nitrogen important in our atmosphere?
• essential nutrient - key ingredient for making things grow
• plant growth - to build important parts like leaves and proteins
• food chain - create the basis of the food chain (plants)
• healthy ecosystem - nitrogen in the air gets converted for plants to use, keeping ecosystems balanced and thriving
Whys oxygen important in our atmosphere?
• respiration - humans and animals need it to breath through respiration
• fire support - O2 (oxygen) help things burn, like in fires and engines
• ozone layer - O3 (oxygen) forms ozone high in the atmosphere which shields us from harmful sun rays
How does the atmosphere protect us?
Earth’s atmosphere makes conditions on earth suitable for living things, it traps energy from the sun keeping the earth warm and water in liquid form and protects Earth from dangerous radiation and meteor collisions.
What are the layers of the atmosphere in order?
bottom to top
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
- Exosphere
What is the altitude of each layer?
Troposphere = 0-12-18 km
Stratosphere = 11-50 km
Mesosphere = 40-50 to 80-90 km
Thermosphere = 80-90 to 800 km
Exosphere = 800 to 3000 km
What is the temperature in each layer?
Troposphere = 15 to -56.5°C
Stratosphere = -56.5 to -2.5°C
Mesosphere = -2.5 to -86.5°C
Thermosphere = -86.5 to 1200°C
Exosphere = 1200°C
How much of the mass of the atmosphere is in the troposphere?
75% even though it is the thinnest layer.
What occurs in the troposphere?
Weather and we live in it
Where is the troposphere thickest and thinnest? What’s it’s average thickness?
It’s thickest at the equator and thinnest at the poles, with an average thickness of about 12km.
What is the the temperature of the air in the troposphere like?
It is warmest near the surface and the air cools as convection currents carry it upwards. The temperature drops until it levels off at the tropopause.
What does the stratosphere contain and what is its job?
The ozone layer, which protects us from dangerous UV radiation.
Why does the temperature increase in the stratosphere?
Ozone absorbs ultraviolet radiation from the sun, causing the temperature to increase throughout the stratosphere. The temperature increases until the stratopause (50km).
What burns up in the mesosphere?
Meteorites
Why does the mesosphere get cool again?
This layer does not absorb any energy from the sun, so it starts to cool again until the menopause around 85km.
What is the air like in the thermosphere?
Very very thin!
What are located in the thermosphere?
The international space station and the Aurora borealis.
Why is the thermosphere so hot?
Solar radiation first hits this layer, so the particles here gain lots of energy. They move rapidly, so they have a very high temperature.
Why does the thermosphere feel cold even though it is hot?
Because there are so few particles to transfer heat to you. Air is so thin you need special instruments to measure the temp.
How long does the thermosphere extend?
690km
How far does the exosphere extend?
For thousands of miles and gradually fades into space.
What orbits in the exosphere?
Satellites
What is altitude/elevation?
The distance above sea level. As altitude increases air pressure decreases, which also decreases density.
What can low density of air cause?
Makes it difficult to breath because you have less oxygen
What is air pressure?
The results of the weight of a column of air pushing down on an area; measured by an instrument called a barometer.
What does gravity cause?
Air to be pulled down towards the earth’s surface
What leads to greater atmospheric pressure?
There is more air pressing down at sea level than in the mountains.
Why is carbon dioxide important in our atmosphere?
Greenhouse effect - the way in which heat is trapped close to Earth’s surface
Plant food - Photosynthesis acts as the lungs of our planet – plants use light and carbon dioxide (CO₂) to make the sugars they need to grow, releasing oxygen in the process
