Details of ozone embedded in a presentation mode for class 9 students for their chapter non metals. The lesson plan is arranged in accordance with ICT model.

1. CLASS : IX C
DATE :
4/01/2020

2. Oxygen
Oxygen is a diatomic molecule.
INTRODUCTION.

3. Content
1. Ozonedefinition
2. Ozone layerformation
3. Ozone layerdepletion
3.1.formationof ozonehole
3.2. effectsof ozonelayerDepletion
3.4. Preventionof ozonelayerDepletion

5. 1. Definition :
 Discovered by Christian Friedrich
Schonbein.
 triatomic molecule containing three
oxygen molecules.
 Found in the stratosphere.
 This layer absorbs UV radiation and
prevents it from reaching the earth.

6. 2. Formation of ozone
layer

7. Ozone layer forms by the conversion of
atmospheric oxygen (O2) to ozone (O3).
The process is known as Chapman cycle.
In the cycle:
 Oxygen absorbs high UV rays and forms
oxygen radical.
This oxygen radicals then reacts with
oxygen molecule and forms ozone.
At this time ozone abdorbs less UV rays
and changes to oxygen molecule.
This cyclic process maintains the ozone
in the atmosphere constant.

10. 3. Ozone layer
Depletion

11. Decrease in the concentration ofozoneand
thinningof ozonelayer is knownas ozone
depletion.
It is observed thatabout 40 -50% of ozone
depletes insouth polar regions.Sucha large
reductionis called as ozonehole.

12. 3.1.Formationofozonehole

13.  Chlorofluorocarbons (CFC) causes the depletion of
ozone layer.
The chemical formula is CFCl3.
CFCl3 released into the atmosphere reach the
stratosphere.
There it undergoes self decomposition.
This chlorine decomposest the ozone molecule into
oxygen.
This disturb the ozone - oxygen cyclic equilibrium
leading to the reduction of ozone.
One Cl atom disturb 1,00,000 molecules of ozone.
Ozone depletion causes the rate of absorption of
UV rays.

15. Ozone layer Depletion
area show in blue color
. (During 2019)

16. 3.2. Effects of ozone
layer depletion

17. (a) Effects on plants
Affects the physiological and
developmental process of plants.
Small spots appear on leafs.
Plant growth is affected.

18. (b). Effects on Marine Ecosystems
Phytoplankton, which forms
the base of the aquatic web
, is affected.
The severe effect is the
decreased reproductive
capacity.

19. (c) Effects on Human beings
Causes non Melanie skin cancer.
Causes the development of cataracts, a
clouding over eye lenses.
Plays a major role in the development of
malignant Melanoma.

20. (d) Effect on Climate
Global warming.
Acid rain.
Green house effect.
Melting of snow.

21. Prevention of ozone
layer Depletion

22. Limit private vehicles driving, to decrease
vehicle emissions.
Replacing CFC's by other materials which
are less damaging.
Grow more and more trees.
Excess use of air conditioners must be
prevented.
Avoid excess use of pesticides.
Use eco-friendly house cleaning agents.

23. Activitytime

24. Draw a Chapman
cycle.
Draw the ozone
layer Depletion
process.

27. Extended learning activity
Write a
note on
the
picture.