TB Page No : 106
• Where does the river Krishna start from ?
Theriver Krishna starts its journey from Mahabaleswarin the Western Ghats
of Maharashtra
TB Page No : 110 ( Think and Discus)
• How do boats float on water?
1. Boats float on water because they are less denser than water.
2. The shape of the boat also allows it to float.
• What material is a boat made up of? Discuss with your teacher.
Ans.
1. Most of the boats are made up of wood.
2. Metals like aluminium and steel are used in making boats.
Experiment :: Sink and Float
Do this and find out
• Fill some water in a pot or a bucket.
• Collect the items given in the list ready.
• Drop each one in the water and examine.
• Before dropping an item, guess whether it will sink into the water or
float on the water and write it in the given table.
TB Page No : 112 ( Think and Discus)
• Do you think there is a relation between rainfall and water transport?
Ans. If there is no rainfall, rivers will not be filled. Water transport
like ships and boats cannot be supported.
• Discuss the causes of water pollution. What are its consequences? How d
we prevent it?
Ans. CAUSES OF WATER POLLUTION:
Consequences
1) Causes diseases like typhoid, cholera, hepatitis.
2) Causes destruction of entire ecosystem.
Prevention
1) Do not dispose household chemicals in water sources.
2) Avoid throwing tissues, wrappers, dust clothes in water sources.
3) Minimize the use of pesticides, fertilizers.
TB Page No : 114
• Why do rivers get flooded?
Rivers get flooded due to heavy rains in the catchment area of the river.
Constructions in these catchment areas increase the effect of floods.
I. Conceptual Understanding:
1. What are the uses
of rivers?
Ans: Uses of Rivers:-
- Rivers are used for irrigation in agriculture.
- Drinking water.
- Used for transportation.
- To produce electricity through hydroelectric dams.
- Leisure activities like swimming and boating.
2. What are the
tributaries of river Krishna?
Ans:
Tributary : A river or stream flowing into a larger river or lake.
Tributaries of river krishna:- Bhima, Gayatri, Ghataprabha. Koyna,
Malaprabha, Munneru, Nira, palem Panchaganga, Tungabhadra, vemna, Wyra are the
tributaries of river’ Krishna’.
3. Write a brief note
on water pollution?
Ans: Water pollution is the
contamination of water bodies, usually due to human activities. The chemical
wastes from the industries and power stations causes large scale damage to the
living organisms in water bodies. Polluted water is not useful for drinking
purpose. It may spread diseases like Typhoid, Cholera, Dysentery, Jaundice,
Amoebiasis and Malaria.
II. Questioning and Hypothesis:
4. What are the
reasons for drying up of rivers? What are the reasons for drying up of rivers
are.
Ans:
- Mainly because of climate change.
- Installation of dams.
- Use of river water for irrigation.
III. Experiments and field obsevations:
5. Collect samples of water from different water
resources and discuss water is suitable for drinking.
Ans:
Student activity.
Out of all the
samples, tap water is considered safe to drink. Tap water is usually treated by
the local municipality. We must also
boil before using it.
IV. Information skills and project work:
6. Collect information
from people on how droughts or floods have affected their life?
Ans:
Floods:
1) They cause huge
damage to lives and property.
2) People lose
their cattle.
3) People have to
shift to rehabilitation centres.
Drought :
1) People suffer
from lack of water for agriculture and fodder for cattle.
2) Migration to new
places.
3) Starvation and death of cattle.
V. Drawing Pictures and Model Making:
7. Make a poster on
how to ” save water” and display in your class.
Ans:
Students activity
VI. Appreciation:
8. Write slogans on
controlling the pollution of rivers?
Ans:
“Think blue and go Green”
“Change your water, change your life”.
“The water you pollute will find its way back to you”.
