stratosphere

stratosphere

There is little mixing between the stratosphere, the layer above the troposphere, and the troposphere below it. The two layers are quite separate. Sometimes ash and gas from a large volcanic eruption may burst into the stratosphere. Once in the stratosphere, it remains suspended there for many years because there is so little mixing between the two layers.

temperature gradient

In the stratosphere, temperature increases with altitude. What is the heat source for the stratosphere? The direct heat source for the stratosphere is the Sun. The ozone layer in the stratosphere absorbs high energy ultraviolet radiation, which breaks the ozone molecule (3-oxygens) apart into an oxygen molecule (2-oxygens) and an oxygen atom (1- oxygen). In the mid-stratosphere there is less UV light and so the oxygen atom and molecule recombine to from ozone. The creation of the ozone molecule releases heat. Because warmer, less dense air sits over cooler, denser air, air in the stratosphere is stable. As a result, there is little mixing of air within the layer. There is also little interaction between the troposphere and stratosphere for this reason.

the ozone layer

The ozone layer is found within the stratosphere between 15 to 30 km (9 to 19 miles) altitude. The ozone layer has a low concentration of ozone; its just higher than the concentration elsewhere. The thickness of the ozone layer varies by the season and also by latitude. Ozone is created in the stratosphere by solar energy. Ultraviolet radiation splits an oxygen molecule into two oxygen atoms. One oxygen atom combines with another oxygen molecule to create an ozone molecule, O3 . The ozone is unstable and is later split into an oxygen molecule and an oxygen atom. This is a natural cycle that leaves some ozone in the stratosphere. The ozone layer is extremely important because ozone gas in the stratosphere absorbs most of the Suns harmful ultraviolet (UV) radiation. Because of this, the ozone layer protects life on Earth. High-energy UV light penetrates cells and damages DNA, leading to cell death (which we know as a bad sunburn). Organisms on Earth are not adapted to heavy UV exposure, which kills or damages them. Without the ozone layer to absorb UVC and UVB radiation, most complex life on Earth would not survive long. Click image to the left or use the URL below. URL: Click image to the left or use the URL below. URL:

instructional diagrams

No diagram descriptions associated with this lesson

questions

as air rises

a) it becomes less dense

b) it becomes warmer

c) the molecules move more freely

-->  d) all of the above

an ozone molecule is created when

-->  a) one oxygen atom combines with one oxygen molecule.

b) two oxygen molecules combine.

c) two oxygen atoms combine.

d) two oxygen atoms combine with two oxygen molecules.

there is a lot of mixing between the stratosphere and troposphere.

a) true

-->  b) false

what is the heat source for the stratosphere?

a) earths surface

b) earths core

-->  c) the sun

d) none of the above

the thickness of the ozone layer varies by the season and by ___.

a) latitude

b) season

c) altitude

-->  d) a & b

what is the cycle of ozone in the stratosphere?

a) uv splits an oxygen molecule into two oxygen atoms, which combine with an oxygen molecule to create ozone.

b) an ozone molecule splits into an oxygen molecule and an oxygen atom.

c) an ozone molecule forms from and then splits into two oxygen molecules and two oxygen atoms.

-->  d) a & b

during a volcanic eruption, ash and gas may burst into the stratosphere and may remain suspended for many years.

-->  a) true

b) false

why is the ozone layer so important?

a) it keeps earths atmosphere from becoming too cold.

-->  b) it protects life on earth from high energy ultraviolet radiation.

c) it provides oxygen to mountain climbers and people in airplanes.

d) it keeps earths atmosphere from becoming too hot.

why do airplanes have their cruising altitude in the stratosphere?

a) there is less friction.

b) there is less turbulence.

c) fuel costs are lower.

-->  d) all of the above.

why is the air in the stratosphere stable?

a) denser air lies above less dense air.

b) cooler air lies above warmer air.

-->  c) warmer air lies above cooler air.

d) a & b

diagram questions

No diagram questions associated with this lesson