Class VI

CHAPTER-4 THE MOTIONS OF THE EARTH (DAY NIGHT AND SEASONS)

D. Answer the following questions in brief:

Q1. What is rotation? How much time does Earth take in completing one rotation?

Ans1- i) The earth is continuously spinning on its imaginary axis from west to east and completes one round in about 24 hours.

ii) The motion of the earth is called rotation.

iii) It causes day and night.

Q2. What is meant by the revolution of the Earth?

Ans2- i) The movement of earth around the sun in an elliptical orbit in one year is called revolution.

ii) It revolves around the Sun in 365⅟4 days.

iii) It causes change in seasons.

Q3. What is a leap year?

Ans3- The year in which February is of 29 days instead of 28 days and we have the year of 366 days is called a leap year.

Q4. What is an equinox? Which seasons are indicated by it in both the hemispheres?

Ans4-

1) The situation when the sun rays are vertical over the equator is called an equinox.

2) The duration of day and night becomes equal in both the hemispheres i.e. 12 hours day and 12 hours night

3) Both the hemispheres receive equal amount of heat.

   It causes spring and autumn seasons in both the hemispheres

Q5- Why does the duration of day and night change in a year.

Ans5- The duration of the day and night changes in a year because:

i) The earth is tilted on its axis. As it orbits the Sun, a different part of the earth faces the Sun.

ii) When the Hemispheres face the Sun, the length of the day is more than night.

iii)  When the hemispheres are far away from the Sun, it is just the opposite. The nights are longer than days.

E. Answer the following questions:

Q1. Why days and nights are equal on 21^st march at all places on the earth? Explain

Ans1- Days and nights are equal on 21^st march at all places on the Earth because:

i) The sunrays are vertical over the equator.

ii) The duration of day and night becomes equal in both the hemispheres, i.e. 12 hours day and 12 hours night.

iii) Both the hemispheres receive equal amount of heat.

Q2. Explain with the help of a diagram, why seasons are reversed between northern and southern hemisphere?

Ans2- i) Position of Earth on 21^st June –

a) Northern Hemisphere is inclined towards the sun thus experiences summer season which is called as summer solstice

b) Southern Hemisphere is away from the sun thus experiences winter season which is called as winter solstice

ii) Position of Earth on 23^rd September –

 Both the hemispheres receive same amount of heat and hence

a) Northern hemisphere – Autumnal equinox

b) Southern Hemisphere – Vernal Equiniox

iii) Position of Earth on 22^nd December-

a) Southern Hemisphere is inclined towards the sun thus experiences summer season which is called as summer solstice

b) Northern Hemisphere is away from the sun thus experiences winter season which is called as winter solstice

iv) Position of Earth on 21^st March

 Both the hemispheres receive same amount of heat and hence

a) Northern hemisphere – Vernal Equinox

b) Southern Hemisphere –Autumnal Equinox

(DIAGRAM ON PAGE NO. 32)

Q3. Why does the month of February have 29 days, after every 4 years?

Ans3- The month of February has 29 days, after every 4 years because:

i) The earth completes one revolution in 365 days and about 6 hours.

ii) We consider 365 days in a year.

iii) The remaining 6 hours are added over a period of 4 years till they become 24 hours or one day.

iv) This extra day is added to the month of February every four years to make it a month of 29 days instead of 28 days.

v) The year of 366 days is called leap year.

Q4. How do day and night occur on the earth? Explain with the help of a diagram?

Ans4- i) The earth completes one rotation in about 24 hours.

ii) So, the earth faces the sun while rotating from west to east.

iii) Each part of the earth facing the sun, is illuminated by sunlight turn by turn.

iv) The lighted half part of the earth that faces the sun has day.

v) While the other part of the earth that is not facing the sun, experiences night.

(DIAGRAM ON PAGE NO.30)

Class VII

Ch 5 – Water surrounding the earth

QUESTIONS AND ANSWERS

D.

Q.1 On what factors does the height of wave depend?

Ans.1 The height of the waves depends on the speed of wind and the duration  of wind blowing from a particular direction.

Q.2 Define an ocean current?

Ans.2 The Ocean current is the continuous movement of a mass of water in a particular direction. Ocean currents are broadly of two types, i.e. cold currents and warm currents.

Q.3 How are tides caused?

Ans.3 Tides are the periodic rise and fall in the level of ocean water. They are caused due to gravitational pull of the moon and the sun. Tides occur twice a day.

Q.4 Name the important components of water cycle.

Ans.4.1. Condensation

          2. Evaporation

          3. Precipitation

Q.5 Name the valuable resources which are found in abundance in the ocean?

Ans. 5  a.  Mineral oil   

            b. Gold   

            c. Platinum

          d. Nickel

       e. Copper

E.

Q.1 How are tides useful to us?

Ans.1 Tides are useful to us in the following ways-

a)   High tides enables big ships to enter the harbour or sail out of the harbour

b)   Tidal energy is harnessed to generate electricity in the coastal areas.

c)   Tidal energy is one of the important renewable sources of energy

Q.2 How are oceans beneficial to us in improving the quality of life?

Ans.1.

1. The Ocean facilitates countries and regions to trade with one another.

2. Good can be moved in a very large quantity by ships and the             transportation is cheaper than any other mode of transport.

3. The marine environment provides animal and plant life for food and trade in abundance.

4. Some of the valuable mineral resources are found in the ocean floor. Mineral oil, manganese nodules, gold, platinum, nickel, copper and cobalt.

5. Several countries are tapping mineral oils as a source of energy in a big way.

Q.3 Explain the water cycle with the help of a diagram.

Ans.3.

1. The sun is the main source of energy which causes water to evaporate.

2. Hence water of the oceans is converted into water vapours due to the heat of the sun by the process of evaporation.

3. The evaporated vapours rise up in atmosphere and condense into tiny crystals of ice or droplets of water to form clouds. 

4. When the condensed ice crystals or water droplets grow in size and are unable to float, they fall down over the earth’s surface as precipitation. 5. It is because of the never ending circulation that process is described as water cycle.

( diagram on pg no. 33)

Q.4 Explain three effects of ocean currents.

Ans.4.

1. The ocean currents play an important role in influencing the climate of the coastal regions of the continents. If a warm current passes along the coast, it raises temperature and makes the place warmer than the surrounding areas. Similarly, cold currents make the adjoining coastal region colder.

2. The confluence of warm and cold currents provides ideal conditions for plentiful growth of plankton, which is a food for marine life. These areas serve as major fishing grounds, encouraging trade and commerce.

3. The ocean currents also help in navigation.

Q.5 Suggest four ways to help people affected by devastation due to tsunami.

Ans. 5.1. Government agencies, non-governmental organisations (NGOs) and residential welfare association, business organisations, shopkeepers, schools and colleges provided relief to the victims by donating money, clothes, medicines, beddings, tents etc.

2. Media played an important role in mobilising public help for the victims.

3. We can also volunteer in the affected areas.

4. Counselling session and blood donating camps can be organised in the areas affected by tsunami.

Class VI

CH-23 OUR RURAL GOVERNANCE

Q1. Mention three levels of the local self – governing bodies under the Panchayati Raj System.

ANS. In rural areas, there are three levels of the local self – governing bodies. 

    a)    Gram Panchayat at the village level.

    b)    Block  Samiti or Panchayat Samiti at the block level.

    c)    Zila Parishad or Zila Panchayat at the District level.

This three- tier system is called as Panchayati Raj System.

Q2. Write the three functions of the Gram Sabha.

ANS. The three functions of the Gram Sabha are :

    A)    Gram Sabha elects the members of Gram Panchayat and its Pradhan or Head –man.

    b)    It takes important decisions about the welfare and development of the village.

    c)    It also approves the annual budget of the Gram Panchayat.

Q3. What is the most important function of Panchayat  Samiti.

Ans3. Large projects like well –equipped hospitals, opening of senior secondary schools, colleges and construction of link roads between the villages, are taken up jointly by some villages.(Block Samiti)

Q4. Write 5 functions of the Panchayat Samiti(Block Samities).

    a)    The panchayat samiti looks after the developmental and welfare work of the villages of a particular block.

    b)    It also looks after agriculture, promotion of cottage industries, poultry, fishery etc.

    c)    It also supervises the projects being undertaken by the village panchayats.

    d)    It helps in the formation of cooperative societies etc.

    e)    It gives advice to the villagers in the field of agriculture, education, medicine, veterinary aid etc

Q5. Mention the sources of income of a Village Panchayat.

ANS. 1.The Village Panchayat gets its income from taxes on houses, market places, use of open spaces etc.

2. It gets grants or aid from the government.

3.  Many a times, it raises loans to complete its welfare and developmental projects.

Q6. How are Panchs and Pradhan (members) of a Gram Panchayat elected?

ANS. 1. Members of Gram Panchayat are directly elected by the Members of Gram Sabha through the process of election.

2. They are elected for a fixed term of 5 years

3. Gram sabha not only elects members of gram panchayat but elects its pradhan or Headmen.

E.

Q1. Mention any five functions of the Gram Panchayat.

ANS. Five functions of the Gram Panchayat are :

    a)    Provisions of clean drinking water.

    b)    Plantation of trees.

    c)    Organization of fairs and festivals.

    d)    Keeping records of births and deaths.

    e)    Provisions of centers of adult literacy.

f   f)     Construction and maintenance of village roads, street lights, public wells, tanks, water ways etc.

Q2. Describe the composition of Zila Parishad.

ANS.1). Elected members of zila parishad parishad .

2)  The Chairman of the Block Samities

3)  Members of Lok Sabha , Rajya Sabha , Vidhan Parishad

4) Representatives of Schedule Caste, Schedule Tribes and women from the district.

5) A President and Vice president is elected from amongst its members.

6.) A permanent government employee acts as Secretary of the Zila Parishad.

Q3. How does the Zila Parishad keep control over the other Panchayati Raj institutions?                         

Or

Q3.  Write any five functions of the Zila Parishad .

Ans-3Five functions of the Zila Parishad are :

 1. It acts as a link between the State Government, Block Samities and the Village Panchayats.

2. It keeps the government informed about the working of local self-governi ng bodies.

3. It prepares plans for over all development of the whole district (in the field of education, agriculture, health care, animal husbandry, village and cottage industries etc).

4. It also implements 5 year Plans and other plans for the rural development.

5. It distributes government funds to Block Samities.

Q4. Differentiate between A Gram Sabha and Gram Panchayat.

Gram Sabha                                                              Gram Panchayat

1. It is the general body of the village.                   1. It is the local self governing body of a village.

2. All men and women who have attained             2. Candidates for contesting the

the age of 18 years , are the registered                elections should be minimum

voters form the Gram Sabha.                                 of 21 years of age.

3. It takes important decision about                       3. It implements decisions taken

the welfare and development of the village.       by the Gram Sabha.

Q5. Highlight the significance of Self-governing bodies in a democracy like India?        Or

                         Why do we need local self-government?

Ans 5.

1) It helps and assists the people of every village or city to meet their community need.  

     2.) These self governing bodies consists of elected representatives of the people.

     3).    It gives an opportunity to the people to develop self-reliance, initiative, power of decision-making.

     4).    It helps the people to participate in the democratic process of the government.  

     5).    It also lessens the burden of the State Government.

Q5. Differentiate between Zila Parishad and Gram Panchayat.

 ZILA PARISHAD

     a)    It is a governing body at the district level.

     b)    It supervises and controls all the samities of the district and also of Gram Panchayat which are under them.

     c)    Its composition – the chairman of the Block Samities , some elected members of Lok Sabha, Rajya Sabha , Vidhan Sabha , Vidhan Parishad , reprentatives of Schedule Caste , Schedule tribes and women.

    d)    It elects President and Vice – President from amongst its members for a term of 5 years.

GRAM PANCHAYAT

   a)    It is a governing body at the village level.

   b)    There is a Gram Panchayat in every village in case of very small villages there is a combined Panchayat for two or three villages.

   c)    Its composition- the members of Gram Panchayat, its Pradhan , Up – Pradhan and Panchayat secretary.

   d)    It elects Panchs for a fixed term of 5 years by the members of Gram Sabha.

                             State government

Secretary                      ß  ZILA PARISHAD           à a) President

                                                                                         b)Vice-President

B.D.O                           ß BLOCK  SAMITI           à a) Chairman

                                                                                           b)Vice President

Panchayat secretary ß GRAM PANCHAYAT          à a) Pradhan

                                                                                         b)Up-Pradhan

                                            RURAL GOVERNANCE

video on volcanic eruption

Class 7 ch 4 PPT

Class VI

Ch-1 The Planet Earth and the solar system                                                       

D: Answer the following questions in brief:-

Q-1 What are celestial bodies?

A-1 The sun the stars, the moon the planets and other objects are all heavenly or celestial bodies.

Q-2 What is ‘’ SAPRISHI MANDAL’’ ?

A-2  Ursa major also called the Great bear, is a constellation of several stars. In India , the seven stars called SAPTRISHI MANDAL , is a part of great bear.

Q-3 Why do stars look very small in the sky?

A-3 Stars are very huge bodies, they look very small as they are very far away from the earth.

Q-4 Name the planets which are gaseous bodies ?

A-4 The planets which are gaseous bodies are Jupiter, Saturn, Uranus and Neptune.

Q-5 Which planet is the closest to Neptune?

A-5 Uranus planet is the closest to Neptune.

E: Answer the following questions:-

Q-1.Derscribe the formation of solar system?

Ans 1

1 Some scientists believe that a giant cloud of gas and dust called the Nebula appeared moving in the space about 4.6 billions of years ago.

2. It cooled and gained very fast rotation.

3. The eight vale of gases of different sizes separated from the Nebula.

4. The remaining central mass of the Nebula changed into a star known as the sun

5. The other eight balls changed into planets.

Q-2 State three features which make the earth a unique planet.

A-2 The three features which make the earth a unique planet are-

   

    1)   The earth receives moderate heat and light from the sun. This much quantity of heat and light is just sufficient to evolve and sustain all forms of life on the Earth's surface. Other pets are either very hot or very cold.

    2)   About two-thirds of Earth's area is covered with water. Water is essential for human beings, animals and plants. No life can exist without water.

    3)   The earth has an envelope of air around it. It contain gases, water vapours and dust particles which help in supporting life on the planet. Earth's atmosphere protects is from the the incoming meteoroids.

Q-3 Mention three main characteristics of a satellite.

A-3 Three main characteristics of a satellite are-

1) The heavenly bodies that revolve around their respective planets are called satellite.

2) Satellite don't have their own light and heat. They reflect light which they receive from the sun.

3)Each planet has one or more satellites, except the Mercury and the Venus.

Q-4 Give a brief description on the phases of moon with the help of a diagram.

A-4 .1 The visible portion goes on increasing gradually day by day after the new moon day.

2. At first, the moon appears in Cresent shape.

3. On eight day, half portion of the moon comes in our view.

4. The full moon becomes visible are 15 days when half of its revolution is completed. The day when the moon is completely visible to us, is the Full Moon Day (Purnima)

5.After this day, the decline of the moons illuminated part starts. The illuminated part slowly disappears and the moon again cooled back to the position of new moon.

DIAGRAM ON PAGE NO. 8

Q-5 Write a short note on the other celestial bodies (asteroid, meteoroids and comets) in the solar system.

A-5

ASTEROIDS- Asteroids are Rocky, space objects that orbit our sun. These can be a few feet wide to several hundred miles wide. Most Asteroids orbit our sun, a star, on a region of space between the orbits of Mars and Jupiter known as the asteroid belt.

METEOROIDS- Meteoroids are little chunks of rock and debris in space. They become meteors is shooting stars when they fall through the Earth's atmosphere, leaving a bright trail as they are heated by the friction of the atmosphere. Most of them break up in the atmosphere before they can strike the surface as meteorites

COMETS- Comets are small bodies with a head and long luminous tail. They are made up of dust and frozen gases. They appear in the sky after a long period of time.