Light and Air Flashcards
Lectures 21-23
What is the electromagnetic spectrum made of?
Photons of light.
What is the speed of light?
2.998 x 10^8 m/s
What does a larger wavelength equal?
Lower energy
What propertie(s) occur when light hits matter?
It can reflect off -Mirror It can pass through -Window -X-ray through soft tissue It can be absorbed -energy is transferred
What is visible light between (in nano-meters)?
400-700 nm
Just past visible light what has longer wavelengths but less energy?
Infrared light (heat)
Just before visible light what has shorter wavelengths but has more energy?
Ultra Violet Light
There was no life on land until 400 million years ago due to the damage done to ___ by __ light.
DNA, UV
What are the type(s) of UV light? What are the wavelengths related to the different type(s)?
UVA: 320- 400 nm
UVB: 280-320 nm
UVC: <280 nm
Which UV light is most damaging to human tissue and DNA, and has the greatest energy but shortest energy?
UVC light
Which UV light has the longest wavelength but shortest energy?
UVA
Which UV light is in the middle for length of wavelength and amount of energy?
UVB
UVC + O2 = 20- how far above the earth does this occur?
30-50 km.
True or false: UVC can reach the surface of the air.
False: No UVC reaches the surface of the air.
What is the chemical equation for ozone?
O + O2 = O3
Which UV light reaches the surface of the earth, and gives us a suntan and bleaches our carpets?
UVA light
O3 + UVB -> O + O2 does what to UVC and UVB light?
Blocks it to the surface of the Earth.
Where does the blocking of UVC and UVB light occur?
Stratosphere
If you removed all elements except ozone and smushed the atmosphere how thick would the atmosphere be? What would it be in Dobson Units?
3 mm thick, or 300 DU
When did drop in the ozone levels appear? How much did they drop by? How long did it take to come back?
The ozone layer dropped by 50% in September of 1984 and returned 6 weeks later.
In 1972 who showed interest in the atmosphere?
Sherwood Rowland
What is a Chlorofluorocarbons? Who invented it and when?
Chlorine and Florine combined with Carbon to make a inert gas. DuPont invented it in 1930 for fridges.
What was Rowland’s experiment on CHC’s? What was the result?
Shined UV light on the ozone (O3)
Shined UV light on a chamber full of CFC’s
-Resulted in the destruction of CFC’s
He shined UV light into a chamber full of ozone and CFC’s
-Resulted in the destruction of both
What did Rowland’s experiment result in?
CFC’s being banned in 1970.
What are the simple steps to the hole in our ozone layer?
- CFC’s travel to the upper atmosphere
- CFC’s are photolysised (split by sunlight) and produce HCl and ClONO2
- PSC’s follow a reaction
- There is a return of UV light
True or False: HCL and CLONO2 do not damage the atmosphere.
True
What is the PSC catalyse that occurs in step 3?
HCl + ClONO2 -> Cl2 + HNO3
Where does all the built up Cl2 get contained?
Vortex walls
Step 1: ClO + UV -> Cl + O Step 2: Cl + O3 -> ClO + O2 Step 3: O + O3 -> 2O2 Final reaction: 2O3 + UV -> 3O What are these the steps for?
CL2 is photolyzed into ClO- what destroys the ozone
How much ozone can ClO removes?
1000 + molecules
What happens when the polar vortex in Antarctica dissipates?
Ozone moves in
True or False: Each time the polar vortex in Antarctica dissipates and the ozone moves in, there’s a little less ozone. This means it will take a long period of time for CFC’s released by past generations to be gone.
True
What is PSC and what does it form? What is it called?
Forms clouds for in the upper atmosphere made of nitric acid- called Polar stratospheric clouds
The loss of ozone occurred in the Antarctic because Mid-winter airmass, surrounded by polar vortex is ___ C.
-90 Celsius
In the 1980’s what did people in Montreal try to use instead of Chlorofluorocarbons? Why?
Hydrochlorofluorocarbons- HCFC
It was just as reactive as CFC but they thought it wouldn’t make it to the upper atmosphere.
True or False: HCFC was just as harmful as CFC and also made it to the upper atmosphere, not like they had intended.
True
In what year will the HCFC levels in our atmosphere be the same as they were before it was uses?
2070
What are some event(s) that can occur when the sunlight hits the Earth?
Reflected back to space -This is why we can see Earth from space Pass through the Earth -Not very likely with our sun. Visible light doesn’t have enough energy. Absorbed by the planet
What is the black body effect?
The idea that when an object is warmer than its surroundings it will emit electromagnetic radiation into your surroundings (in the form of heat).
In black body radiation _________ is dependent on the temperature of the object.
Wavelength
What can can an object emit as it gets hotter and hotter?
Visible Light
How hot is the sun? What kind of light does it emit?
The sun is 5800 kelvin and emits yellow light.
What is the average temperature of the Earth?
15 Celsius
What affects black body distribution?
Average temperature will fall along a distribution curve
Wavelengths will differ depending on the temperature
Earth’s atmosphere affects its distribution
What happens to CO2 when it absorbs energy and becomes warmer?
It vibrates more rapidly and expands.
True or false: O2 is invisible to wavelengths of light, and will not vibrate even if CO2 is present.
False: If there is enough CO2 nearby O2 will start to vibrate.
What two elements are invisible to infra red (IR) radiation?
Oxygen and Nitrogen
CO2, CH4 and N2O do what to the atmosphere?
Trap heat and increase the temperature.
Even though the moon receives the same radiation that Earth does, why does it remain so cold?
Its lack of atmosphere.
What is it called when humans are the reason for the large gas increase in our atmosphere?
Anthropogenic global warming
What are the 3 key gases? Where do they come from?
CO2- burning of fossil fuels and forests
CH4- cows and rice patties
N2O- production of fertilizer
Which key gas has increased by 40% since the industrial revolution?
Carbon dioxide
Which key gas has increased 20% since the industrial revolution?
Nitrogen Monoxide
Which key gas has increased 140% since the industrial revolution?
Methane
What is the definition of “The Greenhouse Effect”?
The trapping in the atmosphere of infra red energy that is leaving the surface of the earth.
What is the definition of “Climate Change”?
The change in long term weather patterns, include temperature, precipitation, wind, etc. due to an increase in the energy in the atmosphere.
What is the definition of “Global Warming”?
The increase in the energy contained in the atmosphere due to increases in the concentration of greenhouse gases .
