RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Rajasthan Board RBSE Class 8 Science Chapter 15 Natural Phenomena

RBSE Solutions for Class 8 Science

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

RBSE Class 8 Science Natural Phenomena Intext Questions and Answers

Page No 163.

Question 1.
happens when we fill up excess air ¡n the balloon?
Answer:
If excess air is filled the balloon will bursts.

Question 2.
Why balloon burst?
Answer:
The balloon bursts due to the excess air pressure inside the balloon.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 3.
What does air do inside the balloon?
Answer:
Air exerts pressure from the inner walls of balloon towards outside in the balloon.

Question 4.
How is air helpful in kite fly, flattening of flag, blowing of dust and leaves etc.
Answer:
This all is possible due to the velocity of air over the air pressure.

RBSE Class 8 Science Natural Phenomena Text Book Questions

Choose the correct Answers:

Question 1.
With the increase in velocity of air, air pressure –
(a) Increases
(b) Decreases
(c) No change
(d) Become double
Answer:
(b) Decreases

Question 2.
What will happen if air blows in between two balloons hanged on wooden stick separated by 10 cm distance –
(a) Balloons come near to each other
(b) Balloons goes away from each other
(c) Balloons burst
(d) No change
Answer:
(a) Balloons come near to each other

Question 3.
Center of cyclone in a clam area. It is called –
(a) Center
(b) Eye
(c) Head
(d) Tail
Answer:
(b) Eye

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Fill in the blanks with suitable words:

  1. Tornado is dark coloured and funnel type ………………….
  2. The air flows from …………………. pressure area to …………………. pressure area.
  3. Breeze produces due to …………………. heating of earth.
  4. Air in motion is called ………………….

Answer:

  1. Clouds
  2. High, low
  3. Uneven.
  4. Wind

Short answer type Questions:

Question 1.
How does cyclone formed?
Answer:
Water takes heat from the atmosphere to Convert to water vapour When this vapour turns into liquid water in the form of rain drops then heat is released in the atmosphere. This released heat makes the nearby air hotter. This hot air rises up leading to a reduction in atmospheric pressure.

the compensate this, air from surronding areas quickly rushes towards it. This cycle is repeated many times. Consequently, as a result of this a low pressure area is formed, around which many layers of air move very quickly in a circular form, like a spiral. This condition of weather is called a cyclone. The centre of cyclone is a quiet zone called an eye.

Question 2.
What type of planning is needed to overcome the cyclone?
Answer:
To deal with cyclone, it is important to take the following measures –

  1. A cyclone forecast and warning service at government or social level and deploying people to the safer places.
  2. People should not ignore the warnings issued by meteorological department and should make necessary arrangements.
  3. Keep all resources ready in emergency conditions. Advanced communication system.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 3.
Describe an activity to explain air pressure.
Answer:
Take a plastic bottle. Fill it half with warm water. Make the bottle empty and immediately cover it with a cap. Put cold water on the surface of bottle. The bottle gets shrunk. Inside bottle some vapours cool down and converts into water. The inner pressure fair from the outside air pressure is reduced. Due to difference in pressure, the bottle squeezes. This shows that air exerts pressure.
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-1

Question 4.
What are the safety measures against the lightning thunder?
(OR)
Write any four safety measures of thunderstorm.
Answer:

  1. Do not stay outdoors, confine yourselves in a building.
  2. Do not come out from your house.
  3. Do not wash clothes and utensils, and do not take bath, etc.
  4. Do not stand under trees.
  5. It is better to confine yourself in car or bus.
  6. Do not sit or lie in open area.

Long answer Questions:

Question 1.
What are the reasons of lightning thunder?
Answer:
Thunderstorm develops in hot humid tropical areas. The rising temperatures produces strong upward rising winds. These winds carry the droplets of water upwards with them, where they condense and fall down again. Falling drops of water are again taken up by rising air. The swift movement of falling droplets of water along with the rising air create lightning and sound. This event is called Thunderstorm.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 2.
Explain, what are the reasons to flow of air ?
Answer:
The regions closer to equator get maximum heat from the sun. This makes air warm which rises up and the air from the regions of low temperature on either side of the equator moves in. The uneven heating between equator and the poles generates wind.

The warm air at those latitudes rises up and the cold wind from the poles rushes in. These region rapidly becomes warm in summer reason. The land’s temperature is more than the temperature of sea. So, the warm air of land rises up and the cold wind from the sea rushes in. These are called wind.

RBSE Class 8 Science Natural Phenomena Important Questions

Objective Questions:

Question 1.
On increasing velocity of air, the air pressure –
(a) increase
(b) decrease
(c) unchanged
(d) None of these
Answer:
(b) decrease

Question 2.
The heat of sun near the equatorial region is –
(a) More
(b) Less
(c) Equal
(d) None of these
Answer:
(a) More

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 3.
Land and water heates up –
(a) Unequally
(b) Equally
(c) Both a and b
(d) None of a & b
Answer:
(a) Unequally

Question 4.
The centre of the cyclone is called –
(a) Thunderstorm
(b) Storm
(c) Eye
(d) None of these
Answer:
(c) Eye

Question 5.
The name of cyclone in American continent is –
(a) Hurricane
(b) Typhoon
(c) Tornado
(d) Ba-wander
Answer:
(a) Hurricane

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 6.
Tornado affected area in India is –
(a) Western Ghat
(b) Eastern Ghat
(c) Northern Ghat
(d) Southern Ghat
Answer:
(b) Eastern Ghat

Fill in the blanks:

  1. In winter air blows from land towards ………………… (sea/upwards)
  2. The air over the land becomes and rises ………………… (cool, up/hot, up)
  3. Water takes ………………… from atmosphere and converts into water vapour. (heat, cold)
  4. Cyclone is a ………………… phenomenon. (artificial/natural)
  5. Air exerts ………………… (pressure/effect).
  6. Moving air is called ………………… (wind/cyclone)
  7. We should not stand at open places during ………………… (Rain/Thunderstorm)
  8. When velocity of air increases, air pressure ………………… (increase/decrease)

Answer:

  1. sea
  2. hot, up
  3. heat
  4. natural
  5. pressure
  6. wind
  7. Thunderstorm
  8. decrease

State True / False:

  1. On increasing the velocity of air, the pressure of air also increases.
  2. In winter air flows from land towards sea.
  3. Cyclone is called Hurricane in Japan.
  4. Tornado arises maximum in our country.

Answer:

  1. False
  2. True
  3. False
  4. False

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Match the Column –

Question 1.
Match the following correctly:
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-2
Answer:

  1. (b)
  2. (d)
  3. (c)
  4. (a)
  5. (c)

Very Short Answer Type Questions:

Question 1.
Sonu overblew a balloon and it burst out, Why?
Answer:
When Sonu overblew a balloon then the air pressure inside the balloon increases which is not tolerated by balloon and it burst.

Question 2.
Why do two suspended balloons come close to each other when they are blown?
Answer:
When one blown between two suspended balloons then the air pressure between the two balloons decreases and the air pressure applied on other parts of the balloons increases and push them closer to each other. Thus they carne close.

Question 3.
What is air pressure ?
Answer:
The pressure exerted by air is called air pressure.

Question 4.
What is the direction of monsoon winds in summer?
Answer:
The direction of monsoon winds in summer is south-west.

Question 5.
What is the direction of monsoon winds in winter?
Answer:
North-west.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 6.
From where to where the wind blows in winter?
Answer:
in winter the wind blows from land towards the sea.

Question 7.
What are thunderstorm?
Answer:
Combination of falling droplets of water and increase in velocity of rising air results in lightning and thundering which is known as thunderstorm.

Question 8.
What is an eye?
Answer:
The centre of the cyclone which is a calm region is called eye.

Question 9.
What are Tornado?
Answer:
Tornado are dark colour funnel shaped clouds. They appear to be coming from sky towards earth plane.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 10.
What is the occurrence of Tornado in, our country?
Answer:
in our country Tornado not occur quite often.

Question 11.
Which areas of India are sensitive for cyclones?
Answer:
India’s east coast is specially sensitive for cyclones.

Question 12.
Who gives the warning before cyclones?
Answer:
Weather Forecast Department.

Question 13.
What is the relation between velocity of air and air pressure?
Answer:
When velocity of air increases, air pressure decreases.

Question 14.
What is the main reason of movement of air?
Answer:
The uneven heating of earth and differences between the temperature of air, land and water causes movement of air.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 15.
Write two work (task) to be performed by public to overcome the cyclone.
Answer:
Two work to be performed by public to overcome the cyclone are:

  1. We should not ignore the warnings issued by the meteorological department on radio, television or public news papers, etc.
  2. We should manage to relocate the essential house items, domestic animals, vehicles, etc. into safe zone.

Question 16.
Why the cold air from sea water starts flowing towards land in summer?
Answer:
In summer, the areas get heated in less lime. Land remains at higher temperature compare to see water. The air above the land gets heated and rises up. This vacated area replaced by cold air from sea water and wind starts flowing.

Short Answer Type Questions:

Question 1.
Give some examples of air pressure from daily life?
Answer:
Examples are –

  1. Flying kite
  2. Bursting of balloon
  3. Fluttering of flag
  4. Blowing off leaves, dust etc.
  5. Collision sound of doors and windows, etc.

Question 2.
“When velocity of air increases, pressure of the air decreases.” Proof with diagram.
Answer:
Activity:
Take two balloons of equal shape and fill them with low quantity of water. Inflate both the balloons and tie them with long thread. Hang these balloons one wooden stick with a distance of 10 cm between them. Blow air between balloons. We will see that both balloons come near each other. Pressure of air decrease when we below between both balloons. Higher pressure on the other side of the balloons push them towards each other. Thus, when velocity of air increases, pressure of the air decreases.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 3.
Why air blows ? Explain with diagram.
Answer:
Area near the Equator receive maximum heat of sun. Due to this, the air near the Earths surface gels heated. Hot air goes up and the cold air from the pole starts flowing to take that place. Due to unequal heating in these regions. wi ud starts flowing.
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-3

Question 4.
What are monsoons ?
Answer:
The land region repidly becomes warm summer season. The temperature of land is more than the temperarure of sea. So. the warm air of land rises up and the cold wind from sea rushes in. These are called Monsoons.

Question 5.
Write information regarding safety measurements taken by government or social level during cyclones.
Answer:
Safety measurements by goernment or social level:

  1. To inform the people about weather forecasts and warming issued by the Meteorological department.
  2. Setup fast communication systems to warm public, government organisations. coastal areas. fishermen and ships.
  3. Arrangements to take people to safe places.

Question 6.
Write a brief note on Tornado.
Answer:
Tornado are dark colour funnel shaped clouds. They appear to he coming from sky
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-4
Towards Earths plane. Tornado move with a velocity less than 180 km/hr. These are weak. Indians east coast is sensitive for cyclones. In our country. Tornado do not occur quite often.

Question 7.
Why the land and sea heates up unevenly?
Answer:
Land heats up faster than the sea. Similarly land cools faster than the sea. This is the reason that land and sea heatens up and cool down unevenly.

Question 8.
Explain that how uneven heating of Earth affects air.
Answer:
The regions closer to equator get maximum heal from the sun. This makes the air warm which rises up and the air from polar regions on either side of equator moves in. These winds blow from the North and the South towards the equator. The uneven heating between equator and the poles generates wind.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 9.
What precautions would you take if you are staying in a cyclone prone area ?
Answer:
Precautions if you are staying in a cyclone prone area are:

  1. We should not avoid alerts or warming issued by meteorological deptt. on TV. ratio etc.
  2. We should avoid driving on roads immersed in water.
  3. We should keep contact number of fire brigade. police medical units ready.
  4. Do not drink water that is contaminated. Always store drinking water for emergencies.
  5. Do not touch wet electric switches and fallen power lines.
  6. You should help your neighbours and friends as possible.

Question 10.
Depict cyclone with diagram (Do not give explanation only diagram required).
Answer:
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-5

Question 11.
Mention one incident of cyclone.
Answer:
On 12 October. 2013, 9.00 PM. the strong winds moving with 220 km/hour strike the sea coastal in Odisha. This cyclone was accompanied by heavy rainfall. Waves rose in sea. As a result sea water entered and flooded the low lying coastal areas. These strong winds and water worsend the situation and damaged the lakh of homes. Agricultural area (hectares in lakh) wave destroyed by these hoods. All poles of electricity got damaged and created blackout. Many peoples died in that incident.

Question 12.
During the cyclone, touching wet switch and hanging or bending down wire have no effect. Do you agree with the statement or not? Write your views.
Answer:
No, ft may cause harmful effect. The people living in cyclone effected area should flot touch wet switch and hanging or bending down wires because there may be flowing electric current in them. During cyclone, many layers of cyclonic wind rotate in the form of coil at a fast speed. Due to which the electric field is generated, which makes electric current more effective in wet switches and fallen electric wires.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Long Answer Type Questions:

Question 1.
Explain the effect of air velocity on air pressure with the help of an activity with diagram.
Answer:
Fake an empty bottle. Make a ball of folded paper. which size is smaller than the mouth of the bottle. Keep this ball near the mouth of the bottle. Let’s try to blow it, inside the bottle. Now repeat this process with bottles of different mouth size.
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-6
We face difficulty when we blow inside the bottle. When we try to bounce a folded paper hail inside a bottle, velocity of air increases and air pressure decreases. Air pressure inside the bottle is higher than the pressure on the bottle’s mouth. Because of this, air which is present inside the bottle propers the ball outside.

Question 2.
How are cyclones formed. Explain with diagram.
Answer:
Water in the atmosphere converts into vapours due to heat. When this water vapour reconverts into water droplet, heal is released in the atmosphere. This heat makes the surrounding air warm. This warm air rises upwards which lowers the air pressure. It is replaced to overcome this cooler air of higher velocity. This cycle repeats. This repetition ends with the formation of low pressure area. Many layers of air surrounding this area rotate with high speed. This occurrence of weather is called as cyclone. At the centre of the cyclone is the eye. There are generally no clouds in the eye and the wind is calm.
RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena-7

Question 3.
What is thunderstorm ? How does it develop ? Mention safety measures from thunderstorm.
Answer:
A thunderstorm is electrical storm, a lightning storm or a thunder shower. It is a type of storm characteristic by the presence of lightning and its acoustic effect on the Earth’s atmosphere known as Thunder. Development of Thunderstorm It develops in hot humid tropical areas. The rising temperatures produce strong upward rising winds. These winds carry water droplets upwards where they freeze and fall down again. The swill movement of falling droplets of water along with rising air create lightning and sound. This is thunderstrom.
Effective Safety Measures from Thunderstrom.

  1. Do not stay outdoors, confine yourselves indoors.
  2. Do not come out from your house.
  3. Do not wash clothes, utensils, etc. and do not take bath.
  4. Do not stay under trees.
  5. You should confine yourselves in car or buses.
  6. Do not sit in open area.

RBSE Solutions for Class 8 Science Chapter 15 Natural Phenomena

Question 4.
Explain effective safety measures at government or social level and actions on the part of people. Also give precautions for those staying in a cyclone prone area ?
Answer:
Effective Safety Measures at Government or Social Level:

  1. A cyclone forecast and warning service by weather forecast department.
  2. Rapid communication of warning to the government agencies, fishermen, the ports, ships and to general public.
  3. Administrative arrangements for moving people fast to safer places.

Action on the Part of Public:

  1. We should not ignore the warning issued by weather forecast department through media like TV, radio or newspaper.
  2. We should make necessary arrangements of essential household goods, domestic animals. vehicle etc. to safer places.
  3. We should avoid driving on roads through standing water.
  4. We should keep ready the phone numbers of all emergency services like police, fire brigade, medical centres. etc.

Precautions for those who are staying in cyclone prone area:

  1. Always store drinking water for emergencies.
  2. Do not touch wet electric switches and
    fallen powerlines.
  3. Do possible help to neighbours and friends.

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