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The atmosphere

The atmosphere. Our Dynamic Earth. The Atmosphere. The atmosphere is the layer of gases that surrounds the Earth. It is made up of several different molecules, such as nitrogen gas, oxygen gas, and carbon dioxide.

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The atmosphere

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  1. The atmosphere Our Dynamic Earth

  2. The Atmosphere • The atmosphere is the layer of gases that surrounds the Earth. • It is made up of several different molecules, such as nitrogen gas, oxygen gas, and carbon dioxide. • The atmosphere is vital to respiration, as it contains both oxygen and carbon dioxide. • It also insulates Earth’s surface, retaining sunlight and heat. • Finally, it helps to filter out UV radiation, which is harmful to living organisms.

  3. The Atmosphere • Nitrogen gas (N2) makes up most of the atmosphere (about 78%!). • Volcanic eruptions and decay emit nitrogen gas. • Oxygen gas (O2) is the second most abundant gas in the atmosphere (about 21%). • Mainly produced through photosynthesis. • The remaining 1% of the atmosphere is a mix of other gases, like carbon dioxide and methane. • The atmosphere also contains many solid and liquid particles, such as dust, pollutants, microbes, and aerosols.

  4. The Atmosphere • Note that the atmosphere is held above Earth’s surface due to gravity. • As such, the atmosphere is much denser close to Earth’s surface. • This is why breathing at high elevations becomes difficult.

  5. Layers of the Atmosphere • The atmosphere can be divided into four sections, based on how temperature changes at each zone.

  6. Layers of the Atmosphere • The first and closest layer is the troposphere, which extends to about 18 km above the surface. • In the troposphere, temperature drops as altitude increases.

  7. Layers of the Atmosphere • The second layer is the stratosphere, which extends from 18-50 km above the Earth’s surface. • This layer contains the ozonelayer (O3), which blocks UV rays. • Temperature rises as altitude increases.

  8. Layers of the Atmosphere • The next layer is the mesosphere. It extends from 50 km to around 80 km. • Once again, temperature drops as altitude increases. • This is the coldest layer of the atmosphere overall.

  9. Layers of the Atmosphere • The farthest layer from the Earth’s surface is the thermosphere. • It is the hottest layer of the atmosphere, though the lack of air particles means that we cannot feel this heat! • Contains the ionosphere, which is responsible for borealis.

  10. Layers of the Atmosphere • Though not part of the atmosphere proper, the exosphere is the volume of molecules at the very edge of the atmosphere. • The air density is so low, that these molecules cannot behave as a gas. However, they are still held in place due to gravity.

  11. Exit Ticket • Which gas is the most abundant in our atmosphere? What is its chemical notation? • List two reasons for the importance of the atmosphere. • Which layer of the atmosphere contains the ozone layer? • Which layer of the atmosphere is the hottest? Would we be able to feel this heat?

  12. Energy in Our Atmosphere • Energy from the sun enters our atmosphere through three possible processes: • Radiation,where energy moves through the atmosphere, which heats the Earth. • Conduction, where energy warms the Earth’s surface directly. • Convection, where warm air rises, heating the environment as it does so.

  13. Energy in Our Atmosphere • Though we receive only a minute portion of the sun’s energy, we still get more than enough to heat the Earth. • Half of the energy we receive is absorbed by Earth’s surface.

  14. Energy in Our Atmosphere • Much of the rest of the energy is scattered (25%) or absorbed (20%) by the atmosphere itself. • Finally, about 5% of the energy is reflected by Earth’s surface. This returns the energy to the atmosphere.

  15. Energy in Our Atmosphere • Energy is also being constantly radiated by the land and seas, which keeps the surface from heating up too much. • Note that dark surfaces tend to absorb more light and more heat. This is why cities tend to have greater temperatures than rural areas.

  16. Energy in Our Atmosphere • Convection currents are circular movements of air, due to the principles of convection. • Remember, warm air rises, cool air sinks. • Due to convection, warm air will rise, warming the environment around it. • In doing so, that air begins to cool down and condense. Cool air sinks, so it descends until it is heated up again. • That starts the process all over again.

  17. The Greenhouse Effect • This is the effect where gases in the atmosphere absorb and trap solar energy. • This is vital – without this principle, Earth would never be warm enough to support life. • Greenhouse gases include water vapor, carbon dioxide, methane and nitrous oxide.

  18. The Greenhouse Effect • Natural and industrial can add to the concentration of greenhouse gases. • It has been theorized that increasing the level of greenhouse gases in the atmosphere could have wide-ranging effects.

  19. Exit Ticket • List the three ways that solar energy heats up the Earth. • ___________ currents are caused by the rising of warm air and the falling of cool air. • Half of the sun’s energy is absorbed by the Earth’s surface. Why doesn’t the Earth overheat due to the built up energy? • Describe the greenhouse effect.

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