(i) Wet clothes take longer time to dry | Class 7 Social Science - Our Environment (Geography) Chapter Air, Air NCERT Solutions

(i) Which of the following gases protects us from harmful sun vays?
(a) Carbon dioxide (b) Nitrogen (c) Ozone

(ii) The most important layer of the atmosphere is
(a) Troposphere (b) Thermosphere (c) Mesosphere

(iii) Which of the following layers of the atmosphere is free from clouds?
(a) Troposphere (b) Stratosphere (c) Mesosphere

(iv) As we go up the layers of the atmosphere, the pressure
(a) Increases (b) Decreases (c) Remains the same

(v) When precipitation comes down to the earth in the liquid form, it is called
(a) Cloud (b) Rain (c) Snow

(i) What is atmosphere?
(ii) Which two gases make the bulk of the atmosphere?
(iii) Which gas creates green house effect in the atmosphere?
(iv) What is weather?
(v) Name three types of rainfall?
(vi) What is air pressure?

(i) Solve this Crossword puzzle with the help of given clues:

(i) Trade Winds                                     (a) Incoming solar energy
(ii) Loo                                                  (b) Seasonal wind
(iii) Monsoon                                        (c) Horizontal movement of Air
(iv) Wind                                              (d) Layer of ozone gas
                                                            (e) Permanent wind
                                                            (f) Local wind

Imagine an ideal environment where you would love to live. Draw the picture of your ideal environment.

(i) There is scanty vegetation in the deserts.
(ii) People of the Sahara desert wear heavy robes.

Observe the photographs given below. These are various features made by a river. Identify them and also tell whether they are erosional or depositional or landforms formed by both.

(i) Ocean water is salty.
(ii) The quality of water is deterioting.

(i) Which is not a natural ecosystem?
(a) Desert (b) Aquarium (c) Forest

(ii) Which is not a component of human environment?
(a) Land (b) Religion (c) Community

(iii) Which is a human made environment?
(a) Mountain (b) Sea (c) Road

(iv) Which is a threat to environment?
(a) Growing plant(b) Growing population (c) Growing crops

(i) Sahara is located in which part of Africa
(a) eastern (b) northern (c) western

(ii) Sahara is what type of desert
(a) cold (b) hot (c) mild

(iii) The Ladakh desert is mainly inhabited by
(a) Christians and Muslims
(b) Buddhists and Muslims
(c) Christians and Buddhists

(iv) Deserts are characterised by
(a) scanty vegetation
(b) heavy precipitation
(c) low evaporation

(v) Hemis in the Ladakh is a famous
(a) temple (b) church (c) monastery

(vi) Egypt is famous for growing
(a) wheat (b) maize (c) cotton

(i) Collect pictures and photographs of forests and grasslands of different parts of world. Write one sentence below each picture.
(ii) Make a collage of rainforest, grassland and coniferous forests.

(i) Name the continent in which the Amazon Basin is located.
(ii) What are the crops grown by the people of the Amazon Basin.
(iii) Name the birds that you are likely to find in the rainforests of the Amazon.
(iv) What are the major cities located on the River Ganga.
(v) Where is the one-horned rhinoceros found?

(i) Glacier                                      (a) Sea shore
(ii) Meanders                                (b) Mushroom rock
(iii) Beach                                     (c) River of ice
(iv) Sand dunes                           (d) Rivers
(v) Waterfall                                 (e) Vibrations of earth
(vi) Earthquake                            (f) Sea cliff
                                                    (g) Hard bed rock
                                                    (h) Deserts

(i) Why do the plates move?
(ii) What are exogenic and endogenic forces?
(iii) What is erosion?
(iv) How are flood plains formed?
(v) What are sand dunes?
(vi) How are beaches formed?
(vii) What are ox bow lakes?

(i) Glacier                                      (a) Sea shore
(ii) Meanders                                (b) Mushroom rock
(iii) Beach                                     (c) River of ice
(iv) Sand dunes                           (d) Rivers
(v) Waterfall                                 (e) Vibrations of earth
(vi) Earthquake                            (f) Sea cliff
                                                    (g) Hard bed rock
                                                    (h) Deserts

(i) Oasis                                                          (a) Libya
(ii) Bedouins                                                   (b) monastery
(iii) Oil                                                             (c) glacier
(iv) Gangri                                                      (d) depressions with water
(v) Lamayuru                                                 (e) cold desert
                                                                       (f) Sahara 

FOR FUN

                                                     Desert Game

This is a class room activity involving all the students. The teacher will create a list of desert creatures. The number of the creatures should be same as the number of students in the class. The creatures can be picked up from the categories of mammals, birds and reptiles. Mammals can include – camel, yak, fox, sheep, goat, antelope... Birds – raven, eagle, vulture, turkey... Reptiles – snakes ... Assign one desert creature to each student. Ask the student to write three characteristics of the creature on plain sheet of paper. (students can use index cards of size 10 cm × 15 cm). Questions such as - in what type of deserts it is
found? Major adaptation? Use to man? These characteristics will be used as clues in the guessing game. On the board make three columns – mammals, birs and reptiles. Paste a sheet of paper in the column under the particular category. The class can be divided in three to four groups. They will compete against each other in the ‘desert game’. Each group now
takes turn in guessing the correct answer. Explain to the class that they have to guess what animal matches the characteristics listed on the paper. For example:
• Animal of hot desert
• Has double set of eyelashes to keep away the sand
• The hide is used for making water bottles
The correct answer is ‘camel’. Within the group there will be a student who has prepared the card. That student should not answer. Ten points are awarded for the correct answer. This game will enable students to understand the desert. You can play the same game by taking different types of fruits, flora and the clothes the people wear.

(i) Man modifies his environment

(ii) Plants and animals depend on each other

(i) Which is not a natural ecosystem?
(a) Desert (b) Aquarium (c) Forest

(ii) Which is not a component of human environment?
(a) Land (b) Religion (c) Community

(iii) Which is a human made environment?
(a) Mountain (b) Sea (c) Road

(iv) Which is a threat to environment?
(a) Growing plant(b) Growing population (c) Growing crops

(i) Name the continent in which the Amazon Basin is located.
(ii) What are the crops grown by the people of the Amazon Basin.
(iii) Name the birds that you are likely to find in the rainforests of the Amazon.
(iv) What are the major cities located on the River Ganga.
(v) Where is the one-horned rhinoceros found?

(i) The name of one river is hidden in each of the sentences below. Spot it. Example:Mandira, Vijayalakshmi and Surinder are my best friends Answer: Ravi
(a) The snake charmer’s bustee, stables where horses are housed, and the piles of wood, all caught fire accidentally. (Hint: Another name for River Brahmputra)

(b) The conference manager put pad, material for reading and a pencil for each participant (Hint: A distributary on the Ganga-Brahmputra delta)

(c) Either jealousy or anger cause a person’s fall (Hint: Name of a juicy fruit!)

(d) Bhavani germinated the seeds in a pot (Hint: Look for her in West Africa)

(e) “I am a zonal champion now” declared the excited athlete. (Hint: The river that has the biggest basin in the world)

(f) The tiffin box rolled down and all the food fell in dusty potholes. (Hint: Rises in India and journeys through Pakistan)

(g) Malini leaned against the pole when she felt that she was going to faint. (Hint: Her delta in Egypt is famous)

(h) Samantha mesmerised everybody with her magic tricks. (Hint: London is situated on her estuary)

(i) “In this neighbourhood, please don’t yell! Owners of these houses like to have peace”. Warned my father when we moved into our new flat”. (Hint: colour!)

(j) ‘Write the following words, Marc!’ “On”, “go”, “in”........ said the teacher to the little boy in KG Class. (Hint: Rhymes with ‘bongo’) Now make some more on your own and ask your classmates to spot the hidden name. You can do this with any name: that of a lake, mountains, trees, fruits, school items etc.

(i) The process by which water continually changes its form and circulates between oceans, atmosphere and land
(a) Water cycle (b) Tides (c) Ocean currents

(ii) Generally the warm ocean currents originate near
(a) Poles (b) Equator (c) None of these

(iii) The rythmic rise and fall of ocean water twice in a day is called
(a) Tide (b) Ocean current (c) Wave

(i) Core                                              (a) Earth’s surface
(ii) Minerals                                       (b) Used for roads and buildings
(iii) Rocks                                          (c) Made of silicon and alumina
(iv) Clay                                             (d) Has definite chemical composition
(v) Sial                                               (e) Innermost layer
                                                          (f) Changes into slate
                                                          (g) Process of transformation of the rock

(i) What are the three layers of the earth?
(ii) What is a rock?
(iii) Name three types of rocks.
(iv) How are extrusive and intrusive rocks formed?
(v) What do you mean by a rock cycle?
(vi) What are the uses of rocks?
(vii) What are metamorphic rocks?