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Suggested Time: 65 minutes. Science TEKS: 3.11, 4.6, 5.1, 5.2, 5.3, 5.4, 5.5. Math TEKS: 5.11, 5.14, 5.15

Objective

Students have already learned about the most common gases in the atmosphere. Now they will begin to learn about how other substances in the atmosphere can strongly affect their health and the environment, even in minute concentrations. In this lesson, students will learn about stratospheric ozone and the difference between this high-level ozone (which protects the Earth from ultraviolet radiation) and low-level ozone (which is an air pollutant).

Stratospheric ozone forms naturally and protects us from ultraviolet radiation. Tropospheric ozone forms from air pollutant emissions and harms human health.Credit: U.S. EPA: “Ozone Good Up High, Bad Nearby”

Background information

Most of the oxygen in the atmosphere, and the type that we need to sustain life, has two atoms per molecule (O2). Ozone , by contrast, has three oxygen atoms (O3). Ozone forms naturally in the stratosphere when intense ultraviolet radiation from the Sun splits an oxygen molecule (O2) into two O atoms. Each O can then combine with another O2 to form O3. [Note: The concept of molecules composed of atoms is above the 5th grade level; for your explanation to students, you can state that the Sun’s intense UV radiation splits oxygen to form ozone].

About 90 percent of the ozone in the Earth’s atmosphere is found in what is known as the ozone layer in the stratosphere (about 10-30 miles above Earth’s surface). The ozone layer absorbs most of the Sun’s ultraviolet radiation to shield us from these damaging rays. Ultraviolet rays can cause a range of negative effects: they can cause cancer, burn skin, damage eyes, weaken the human immune system, and harm both plants and animals. In fact, estimates show that a one percent reduction in the ozone layer results in a two to five percent increase in the number of cases of cancer!

Certain air pollutants can damage the ozone layer. The most dramatic depletion of the ozone layer is the Antarctic ozone hole . In the early 1980s, scientists discovered major thinning of the ozone layer above Antarctica during springtime . In fact, they observed nearly 70% less ozone than had been found there previously! Scientists realized that the depletion of the ozone layer is caused by the release of certain chemicals such as chlorofluorocarbons (CFCs) into the atmosphere. Just a few decades ago, CFCs were used in air conditioners, aerosol sprays, and cleaning products. When CFCs reach the stratosphere, they react with the sunlight to release chlorine atoms, which can destroy ozone molecules. In 1989, an international agreement known as the Montreal Protocol was signed to ban the most destructive ozone-depleting gases and preserve the ozone layer. If the agreement is adhered to, it is hoped that the ozone layer will completely recover by 2050.

From September 21-30, 2006 the average area of the ozone hole was the largest ever observed. In this image, from Sept. 24, 2006, the Antarctic ozone hole was equal to the record single-day size of 11.4 million square miles.Credit: http://www.nasa.gov/centers/goddard/news/topstory/2006/ozone_record.html

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Rice air curriculum. OpenStax CNX. May 09, 2010 Download for free at http://cnx.org/content/col11200/1.1
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