JAN- FEBRUARY 2012
PART 1
PART 1
Circle the best answer.
3. Which of the following statements are true?
1. The list below states examples of Man’s negative impacts
on the environment except:
A. deforestation
C. water pollution
PATHFINDER SCIENCE WORKSHEET
B. global warming
D. biotechnology
2. Study the picture below.
I.
Car, trucks and other combustion engine vehicles
cause air pollution.
The burning of fossil fuels contributes to smog.
Pesticides, insecticides and herbicides all cause air
pollution.
Petroleum refineries release hydrocarbon that
pollute the air.
II.
III.
IV.
A. I and II only.
C. II and III only.
What could be cause of the situation in the picture
above?
A. Transportation.
C. Disposal of
industrial waste.
B. Open burning.
D. Construction
activities.
B. III and IV only
D. All of the above
4. Deforestation is the clearing or removal of trees from
an area of woodland or forest for many differing
reason usually commercial.
Which of the following is not the effects of
deforestation?
A.
B.
C.
D.
Loss of food source and habitat for wildlife.
Rising levels of carbon dioxide in the atmosphere.
Acid rain.
Soil erosion.
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PART 2
Answer the questions in the spaces provided.
5. Study the picture below.
b. Explain 2 causes of the greenhouse effect.
______________________________________________________________
______________________________________________________________
______________________________________________________________
c. List four ways to reduce global warming.
1. ___________________________________________________________
2. ___________________________________________________________
3. ___________________________________________________________
4. ___________________________________________________________
a. Provide the definition of the greenhouse effect.
______________________________________________________________
______________________________________________________________
______________________________________________________________
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Answer Scheme
1. D. biotechnology
SMART TIPS:
A general description of biotechnology is using living
things to create products or to do tasks for human
beings. Biotechnology is the practice of using plants,
animals and micro-organisms such as bacteria, as well
as biological processes - such as the ripening of fruit
or the bacteria that break down compost - to some
benefit. Plant biotechnology offers the potential to
produce crops that not only taste better but are also
healthier.
2. C. Disposal of industrial waste.
SMART TIPS:
Many industrial facilities use freshwater to carry away
waste from the plant into rivers, lakes and oceans,
which leads to water pollution. With an exploding
human
population
and
urbanization,
more
construction activities are taking place to create
infrastructures like homes, offices, roads, buildings
and factories. Construction activities are another
significant cause of land pollution. Open burning is
any open flame exposed to the environment, where
pollutants produced from the fire are emitted directly
into the surrounding air. This includes the burning of
leaves, wood and trash. Open burning is a very
common, yet very unhealthy method of garbage
disposal.
3. D. All of the above.
SMART TIPS:
Factories, office buildings, homes and power-generating
stations burn fossil fuels, which cause air pollution. The
burning of oil and coal (fossil fuels) also contributes to
smog. This air pollution destroys plants, damages
buildings and creates oxidation on iron. Pesticides that
people use to kill indoor and outdoor pests, insecticides
that kill insects and herbicides that is used to kill weeds,
all cause air pollution. Petroleum refineries release
hydrocarbons and various particulates that pollute the air.
Cars, trucks, jet airplanes and other combustion engine
vehicles cause air pollution. The exhaust from these
contains carbon monoxide, nitrous oxide and gaseous
oxide.
4. C. Acid rain.
SMART TIPS:
Acid rain is caused by a chemical reaction that begins
when compounds like sulfur dioxide and nitrogen oxides
are released into the air. These substances can rise very
high into the atmosphere, where they mix and react with
water, oxygen, and other chemicals to form more acidic
pollutants, known as acid rain. Human activities are the
main cause of acid rain. Over the past few decades,
humans have released so many different chemicals into
the air that they have changed the mix of gases in the
atmosphere. Power plants release the majority of sulfur
dioxide and much of the nitrogen oxides when they burn
fossil fuels, such as coal, to produce electricity. In addition,
the exhaust from cars, trucks, and buses releases nitrogen
oxides and sulfur dioxide into the air. These pollutants
cause acid rain.
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5. a. The greenhouse effect is a natural phenomenon
leading to the warming of the atmosphere and surface
of a planet, exposed to solar radiation.
or
The greenhouse effect is the steady increase in the
Earth’s lower atmosphere (near surface) temperature
due to heat retention caused by the accumulation of
greenhouse gases (including water vapor, carbon
dioxide,
methane,
nitrous
oxides
and
chlorofluorocarbons or CFCs).
( Accept any suitable answers.)
b. The causes of the greenhouse effect are:
1) Burning natural gas, coal and oil including
gasoline for automobile engines, raises the
level of carbon dioxide in the atmosphere.
2) Some farming practices and land-use changes
increase the levels of methane and nitrous
oxide.
3) Many factories produce long-lasting industrial
gases that do not occur naturally, yet
contribute significantly to the enhanced
greenhouse effect and "global warming" that is
currently under way.
4) Deforestation also contributes to global
warming. Trees use carbon dioxide and give off
oxygen in its place, which helps to create the
optimal balance of gases in the atmosphere. As
more forests are logged for timber or cut down
to make way for farming, there are fewer trees
to perform this critical function.
5) Population growth is another factor in global
warming, because as more people use fossil fuels
for heat, transportation and manufacturing the
level of greenhouse gases continues to increase. As
more farming occurs to feed millions of new
people, more greenhouse gases enter the
atmosphere.
( Accept any suitable answers.)
c. 1. Reduce, Reuse, Recycle
2. Use less heat and air conditioning.
3. Drive less and carpool whenever possible.
4. Buy energy- efficient products.
5. Switch off appliances when not in use.
6. Plant a tree.
( Accept any suitable answers.)
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