Copy of PS AR RS P6L23 Man's Impact on the Environment WS

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Topic: MAN’S IMPACT ON THE ENVIRONMENT (LESSON 23)

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Primary 6: Rocket Science

Lesson Outline

• Notes
• Activity 1: Hands-on Activity
• Activity 2: MCQs
• Activity 3: Open-ended Questions
• Activity 4: Fun Facts

Primary 6: Rocket Science

Man’s impact on the environment – NOTES

Our Activities Have an Impact on Our Environment

• We carry out many activities to meet our needs eg. growing crops for food.
o All our activities have an impact on our environment.

• If our activities are helpful to the environment, then our impact on the environment
is positive.

• If our activities are harmful to the environment, then our impact on the
environment is negative.

Negative Impact on the Environment

• We use natural resources to meet out needs. Some natural resources include
plants, animals, air, water, metal, oil, coal, etc.

• We carry out many activities to meet our needs and end up using huge amounts of
natural resources. Oil, coal and most metals will be completely used up one day.

• The activities that we carry out have harmful effects on the environment, such as
o Pollution includes littering, smoking, CFCs, acid rain
o Using up natural resources which can lead to global warming and the loss of
living things.
o Deforestation which can lead to soil erosion, global warming and the loss of
living things.

• Pollution
o Pollution is caused by releasing pollutants into the environment. A pollutant is
any substance that makes the environment dirty or harmful to live in.
o Pollution can affect the land, the air and water bodies such as the seas.

• Using up natural resources
o Natural resources such as oil, coal and petrol will one day be used up.
o Oil, coal and petrol produce smoke (can lead to air pollution) and carbon
dioxide (a greenhouse gas) when burnt to release energy.
o Some animals are already in great danger of becoming extinct.

• Deforestation
o Deforestation is the clearing of large areas of forested land by cutting and
burning down trees.
o Deforestation can result in
 the loss of living things as they lose their homes, become exposed to
predators and the weather, and may die.
 soil erosion as there are no more plants with roots to keep the soil
together.
 soil erosion could lead to water pollution with murky water affecting
the ability of producers to photosynthesize. This will then have a
cascading effect on all the consumers in the food web thereby
effecting the whole water system ecosystem.

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Primary 6: Rocket Science

Man’s impact on the environment – NOTES
• Global warming

o Greenhouse gases (such as carbon dioxide) trap heat from the Sun to keep the
Earth warm. When there is more carbon dioxide in the air, more heat is trapped
causing the temperature of Earth to rise. This leads to global warming.

o Effects of global warming:
 Melting of polar ice caps
 Rise in sea levels
 Destruction of coastal habitats
 Erratic weather changes (droughts, wildfires, hurricanes)
 Food shortages

Positive Impact on the Environment
Man can make a positive impact on his environment through conservation and
reforestation.
• Conservation

o We can conserve natural resources by reducing, reusing and recycling
 Reduce the amount of water usage
 Use public transport to reduce pollution
 Reduce plastic use
 Recycle paper and save trees
 Protection of wildlife
 Reducing waste by creating more biodegradable materials

• Reforestation
o Reforestation refers to the process of planting seeds or young trees in
deforested areas. Reforestation is important as it helps to restore the habitats
affected by deforestation.
 As trees photosynthesise and take in carbon dioxide, it helps to counter
global warming as the amount of greenhouse gases is lowered.
 The presence of replanted trees reduces soil erosion and water pollution.
 As the forest is restored, wildlife will also return to repopulate the area,
preserving the continuity of the organisms there.

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Primary 6: Rocket Science

Activity 1 – Hands-on Activity: The climate time machine
Online resource:
https://climatekids.nasa.gov/time-machine/
https://www.nationalgeographic.org/interactive/human-impacts-environment/
Introduction:
1. This time series shows global

changes in the concentration and
distribution of carbon dioxide.
2. It will show a progression of
changing global surface
temperatures since 1884 due to
rising carbon dioxide levels.
3. This visualization also shows the
annual Arctic sea ice minimum
since 1979 with increasing
global temperatures.
4. This visualization shows the
effect on coastal regions due to
the melted ice.

Discussion questions:
1. The sea ice cover reaches its minimum extent at the end of each summer.

Why is this so?

2. What causes the rise in sea levels?

3. What are the reasons why carbon dioxide levels are increasing every year?

4. Explain greenhouse effect and global warming.

5. Have fun with kahoot on:
https://www.nationalgeographic.org/interactive/human-impacts-environment/

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Primary 6: Rocket Science

Activity 2 – MCQs

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Primary 6: Rocket Science

1. Which of the following is a result of deforestation?

(1) More rain will fall. ()
(2) More soil will be eroded.
(3) More oxygen will be given out into the air.
(4) More carbon dioxide will be absorbed from the air.

2. Tom set up an experiment as shown below to find out how plants affected soil erosion.
He used the same type of plants for his experiment. He would pour water into the soil
and after some time, water and soil would flow into the bowl.

plants soil

container pipe
bowl

Which of the following variables should Tom keep the same to ensure a fair test?

A. amount of roots in the soil ( )
B. amount of soil in the container
C. amount of water and soil collected
D. amount of water poured into the soil

(1) A and C only
(2) A and D only
(3) B and C only
(4) B and D only

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Primary 6: Rocket Science

3. The flow chart below shows man’s impact on the environment.

clearing of forest

resulted in soil exposed Q
P to rain

caused

more carbon
dioxide in the air

led to

trapping more heat R
from the sun

What could P, Q and R be?

P Q R
(1) deforestation soil erosion global warming

(2) deforestation global warming air pollution

(3) air pollution soil erosion global warming

(4) global warming deforestation air pollution

()

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Primary 6: Rocket Science

4. The picture below shows activities taking place during recess in a school canteen.
ceiling lights

Wash your
hands with soap

Which of the following actions by the students are environmentally friendly?

A. Turn off the water taps when they are not in use.
B. Throw all rubbish into the same dustbin.
C. Switch off the ceiling lights when it is bright.
D. Use disposable plates instead of plastic ones.

(1) A and C only ( )
(2) B and D only
(3) A, B and C only 9
(4) A, B, C and D

Primary 6: Rocket Science

5. The poster below provides some information on how sea turtles reproduce.

Information on the Sea Turtles

An adult female sea turtle lays her eggs at a
quiet, dark beach, covers it, leaves it behind
and returns to the sea.

After 45 to 70 days, the baby sea turtles begin
to break out of their eggs and crawl to the sea.
They use the natural light sources around
them, such as the moon, to help guide them to
find the sea.

During the process of finding the sea, bright
lights near the shore can cause these baby
turtles to become confused and disoriented to
wander inland, where they often die of
dehydration or predation.

Which of the following human activities is likely to cause a negative impact on the
sea turtles?

(1) keep the beach free of litter
(2) light campfires along the beaches at night
(3) switch off vehicle lights when at the beach
(4) avoid using cameras with flashes at the beach

( )

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Primary 6: Rocket Science

6. Substance A was used to kill pest P that had been feeding on the plants in a garden.
The graph below shows the number of pest P in the garden over the past five months.
X, Y and Z indicate the times substance A was sprayed on the plants.

Number of pest P

50 Month
40 X

Y
30 Z
20

10

0
1st 2nd 3rd 4th 5th

From the graph, which of the following can be inferred about substance A?

(1) It has no effect on the population of pest P.

(2) It causes the number of pest P to increase and decrease.
(3) It is getting less effective in controlling the population of pest P.
(4) It is getting more effective in controlling the population of pest P.

( )

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Primary 6: Rocket Science

7. The four graphs below show the changes in global sea levels over a period of time.
Which one of the following most likely shows the effect of continual deforestation
activities on the sea level over time?

(1)

Sea level

Number of years

(2)
Sea level

Number of years

(3)
Sea level

Number of years

(4)
Sea level

Number of years ()

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Primary 6: Rocket Science

8. The diagram below is a representation of human’s activities and the effects on the
environment.

A soil Difficult for new
B
exposed plants to grow

to rain

fewer trees

C more carbon dioxide in the air

more heat from the D sea level increases

Sun is trapped

What do A, B, C and D represent?

AB C D
global warming
(1) soil erosion burning deforestation
fossil fuels

( 2 ) deforestation soil erosion global warming burning fossil fuels

( 3 ) soil erosion deforestation global warming burning fossil fuels

(4) deforestation soil erosion burning fossil global warming
fuels

( )

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Primary 6: Rocket Science

9. The graphs below show the increase in the average temperature of air around Area A and
Area B from Year 1995 to 2015.
Temperature (oC)

Area B

Area A

1995 2015 Year

Which of the following activities could have caused the temperature around Area B to
be higher than the temperature around Area A?

A. A decrease in the use of fossil fuels.
B. An increase in the cutting down of trees in Area B.
C. A decrease in the use of air-conditioners in Area B.
D. An increase in the number of vehicles on the road in Area B.

(1) A and C only
(2) B and D only
(3) A, B and C only
(4) B, C and D only

()

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Primary 6: Rocket Science

10. The diagram below shows a river where two aquatic organisms, P and Q, can be
found. There is a factory located near the river which releases its waste products into
the river. The waste products cause the population of organism P to increase but the
population of organism Q to decrease.

Flow of river

Location A

Location B

Clear water Location C
Location D

The table below shows the population of organisms P and Q present in samples taken
at four different locations A, B, C and D of the river.

Location Population of P Population of Q

A 15 88
B 16 85
C 30 37
D 17 42

Based on the results, which one of the diagrams below shows where the factory is
located to cause the most impact on the organisms?

Flow of river
(1) Location A

Location B

Clear water Location C

Factory
Location D

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Primary 6: Rocket Science

(2) Flow of river

Clear water Location A
(3)
Location B
Clear water
Factory Location C

(4) Location D

Clear water Factory

Flow of river

Location A

Location B

Location C

Location D

Flow of river

Location A

Factory
Location B

Location C

Location D ()

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Primary 6: Rocket Science

Activity 3 – Open-ended Questions
1. Ali wanted to conduct an experiment to find out if plants help to reduce soil

erosion. He set up the experiment shown below using two trays, X and Y,
containing the same amount and type of soil. Tray X has grass growing on the
soil while tray Y contains only soil.

tray X basin tray Y

Set-up 1 Set-up 2

Ali then poured an equal amount of water from a watering can onto each tray. He [1]
observed the amount of soil washed off from each tray, into the basins.

At the end of his experiment, Ali concluded that plants help to reduce soil erosion.

(a) What observation in the set-ups could have helped Ali make his conclusion?

(b) State how the roots of plants help to reduce soil erosion. [1]

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Primary 6: Rocket Science

We often see exposed bare mud slopes covered with large plastic sheets along the
sides of roads as shown below.

plastic sheet slope

(c) Based on Ali’s experiment, explain why plastic sheets are used to cover the [1]
slopes.

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Primary 6: Rocket Science

2. The graph below shows the change in temperature on Earth in the last few
hundred years. An increase in greenhouse gases is responsible for the change in
temperature.
temperature
change (°C)

1800 1900 2000 year

(a) How does the increase in greenhouse gases cause the change in temperature on

Earth? [1]

(b) Explain how excessive cutting down of trees can lead to global warming. [1]

Organism L lives in cold places. During winter, their habitat is covered in snow and
during summer, the snow melts away and their habitat is covered with grass and
bushes. Organism L has white fur during winter and brown fur during summer.

organism L

(c) With global warming, the weather patterns have changed. The snow is melting earlier

and during some winter months, there is hardly any snow. Explain how this can cause

the population of organism L to decrease. [1]

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Primary 6: Rocket Science
Activity 4 – Fun Facts: Why Singapore Is Heating Up 2x Faster Than The Planet

https://www.youtube.com/watch?v=UrQ9zjvmD6k
Discussion Questions:
1. Sweating is a natural cooling mechanism? How is this so?
2. Sweat does not dry up as fast in Singapore as compared to some other
places in the world. What weather condition is causing this?
3. What is urban heat island effect? What is the main cause of this effect in
Singapore? (2.00 min)

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