CLASS VI . SCIENCE

SEPARATION OF SUBSTANCES

Q.1 Multiple choice questions (Choose the correct option)

(A) Most of the substances we see around us are

       (a) Pure Elements                 (b) Pure Compounds                  (c) Mixtures

(B) A solution of salt in water is a?

       (a) Compound                      (b) Homogeneous Mixture          (c) Heterogeneous Mixture                      

        (d) Element

(C) The property used in separating a mixture of two solids by winnowing is

      (a) difference in color                                        (b) difference in size

      (c) difference in weight                                      (d) Attraction by magnet

(D) Which method is used to obtain pure liquid from a solution?

     (a) Distillation                                                        (b) Condensation

      (c) Filtration                                                            (d) Loading

(E) Which of the following can dissolve in water?

    (a) Only Solids                                                         (b) Only solids and liquids

    (c) Solids, liquids & gases                                     (d) only liquids

Q.2 What is separation?

Q.3 Why the separation of substances is necessary?

Q.4 What is the basis of separation of components of mixture?

Q.5 When do we use hand picking as the method of separation?

Q.6 What is threshing? How is it done?

Q.7 Define winnowing? What is the principle of using winnowing as method of separation?

Q.8 Where do we find sieving as the method of separation?

Q.9 You are given a mixture of sand, salt and iron filling. Suggest some methods for separating all the components of this mixture?

Q.10 Define filtration? Give 3 examples where filtration method is used.

Q.11 What is evaporation? Where do we use this method at home?

Q.12 What method is used to separate salt from sea water and how?

Q.13 In which cases handpicking is enough as a method of separation?

Q.14 One method of separation is not enough. Comment.

Q.15 Differentiate between a pure substance and a mixture.

Q.16 Is the separation of two immiscible liquids using separating funnel same as decantation?

Q.17 What do you use to remove discarded tea leaves from tea?

                                                                                class- VI

Changes Around Us

FILL IN THE BLANKS

1. The changes that can be reversed are called ______________ changes.

2. The changes that cannot be reversed are called ______________ changes.

3. On heating , the metals _________________

4. On cooling , the metals _________________

5. Burning of incense stick is an ___________________ change.

6 On heating metal rim _______________ and fits into the wooden wheel.

CHOOSE THE CORRECT ANSWER

1 Ripening of fruit is a ( reversible / irreversible ) change.

2 In ( reversible / irreversible ) change we cannot get back the original components.

TRUE OR FALSE

1. Growing of trees is an irreversible change. _________

2 Formation of curd from milk is a reversible change .___________

NAME THE FOLLOWING

1 Name any two reversible changes .

2 Name any two irreversible changes.

DISTINGUISH BETWEEN

Reversible and Irreversible changes

CLASSIFY THE FOLLOWING CHANGES INTO REVERSIBLE AND IRREVERSIBLE CHANGES

1 Crumpling of paper

2 Burning of paper

3 Sawing of wood

4Cooking of food

5 Change of water into water vapour

6 Ironing of clothes

 SCIENCE CLASS VI

Unit-15 AIR AROUND US

Q1) Fill in the blanks:

       1. The envelope of air that surrounds the earth is known as __________.

       2. Air is a __________of many gases.

       3. Burning of a substance can occur only in the presence of __________.

       4. The major component of air is __________.

       5. Plants use __________ for photosynthesis and __________ for respiration.

       6. All living organisms take in_________and give out_____________during respiration.

       7. The burning of fuels produces __________ gas.

      8. __________ contains few gases and fine dust particles.

      9. Animals and plants living in water use oxygen __________ in water.

     10. __________ and __________ present inside the nose prevent dust particles to enter into the respiratory system.

     11. Two processes which maintain balance of carbon dioxide and oxygen in nature are __________ and __________.

     12.Air in motion is called__________.

Q2) Why do mountaineers carry oxygen cylinders with them?

Q3) What is the composition of air.

Q4) The process in which water vapour changes into water droplets is called condensation. What conditions are required for this process to occur?

Q5) What happens when burning continues in a closed room?

                                                                                class -VI

Components Of Food

FILL IN THE BLANKS

1. The main carbohydrates found in our food are in te form of __________ and ______________.

2. Carbohydrates and fats provide ______________ to our body .

3. Foods containing carbohydrates and fats are also called ______________ giving foods.

4. Foods containing proteins are often called _________________________ foods.

5. Vitamin ________ gets easily destroyed by heat during cooking.

6. Over eating fat rich food leads to ________________

7. Deficiency diseases can be prevented by taking a _______________ diet.

8. _____________ help in protecting our body against diseases.

NAME THE FOLLOWING

1. Two sources of carbohydrates . __________________ _____________

2. Two sources of fats __________________ _____________

3. Two sources of protein __________________ ____________

4. Two sources of vitamin C __________________ ____________

5. Disease caused due to deficiency of iron ______________

6. Disease caused due to deficiency of vitamin A _____________

7. Disease caused due to deficiency of iodine_____________

TRUE OR FALSE

1. Dietary fibres are also known as roughage. _________

2. Minerals are needed by our body in large quantity. ___________

3. Our body prepares vitamin D in presence of sunlight. __________

DEFINE THE FOLLOWING

1Nutrients 2 Balanced diet 3 Deficiency diseases

Science Class - VII

MOTION AND TIME

Q1. Define speed. State its S. I. unit.

Q2. Differentiate between uniform and non-uniform motion.

Q3. Describe a simple pendulum. Draw a diagram. What kind of motion does it show?

Q4. For a simple pendulum; define:-

        a) One oscillation

        b) Time period

        c) Frequency

Q5. A truck travels a distance of 540 km in 4.5 hours. Calculate its speed.

Q6. The distance between two stations is 1995 km. How much time it will take to cover this distance at an average speed of 19 km/h?

Q7. A car takes 20 minutes to cover a distance of 15 km. Calculate its speed in km/h

Chapter 2

 Nutrition in Animals

Fill in the blanks:

1. The mode of taking food into the body is called ___________________

2. In the process of ________________ food is broken down in to simpler substances.

3. The _______________ canal start with mouth and ends in anus.

4. ___________________glands are present in mouth.

5. Saliva helps in the digestion of ___________________ in food.

6. _____________ are the sensory cells present in mouth.

7. The digestive juices of the stomach digest the _____________ in the food.

8. The ________________released by the bacteria in the mouth causes tooth decay.

9. Liver secretes ____________ and helps in the digestion of ____________in the food.

10. During the process of digestion, the carbohydrates break down to _________, the proteins into ______________ and the fats into ______________.

11. Faecal matter is removed from the body by the process of __________

12. _____________ of amoeba helps to capture food.

13. The patient suffering diarrhea should be treated with ___________.

14. We get hiccups or cough, if by chance food particles enters the ____

15. Partially digested food in the rumen of herbivores is called ________

16. The process of utilizing absorbed food particles(nutrients) into the living cells is called ________________.

II) Name the following :

1. 4 types of teeth.

2. Digestive glands in human body.

3. Acid produced in stomach.

4. Scientist who discovered the working of stomach.

5. The sac like structure present between the small intestine & large intestine in ruminants.

.

Chapter 4

 Heat

Fill in the blanks :

1. ______________ is a device used for measuring temperature.

2. The materials which allow heat to pass through them easily are __________ of heat.

3. Clinical thermometer is used to measure our _____________

4. Wool is poor __________________ of heat and it has air trapped in between the fibres.

5. In ______________ generally the heat is transferred by conduction.

6. _______________ metal is used in the bulb of the thermometer.

7. The normal temperature of the human body is __________

True or False :

1. The materials which do not allow heat to pass them easily are called insulators.

2. In liquids and gases the heat is transferred by conduction.

3. A kink near the bulb of a clinical thermometer prevents mercury level from falling of its own.

4. We get heat from the sun by radiation.

5. Digital thermometers contain mercury

                                    MATTER AND CHEMICAL FORMULAE

 Write the symbols of the following elements

1) Zinc                 6) Phosphorus

2) Manganese             7) Nickel

3) Potassium                8) Calcium

4) Calcium          9) Lead

5) Gold                10) Neon

Write the formula of the following compounds

1) Nitric acid                           5) Potassium carbonate

2) Ammonia                            6) Calcium dioxide

3) Sodium hydroxide             7) Carbon monoxide

4) Hydrogen chloride           8) Sulphuric acid

9)calcium carbonate.            10) carbondioxide.

Lesson 14

                         Chemical effects of Electric Current

I Fill in the blanks:

1. Distilled water is _____________ of electricity.

2. The dissociation of chemicals into ions due to the passing of electricity through it is the _____________ of electricity.

3. The distilled water becomes _____________ of electricity on dissolving salt in it.

4. _____________ are wires/rods/plates through which electricity enters of leaves an electrolyte.

5. The longer lead of LED is always connected to the positive terminal of the battery.

6. Name two liquids that conduct electricity _____________.

7. The passage of electric current through liquids causes _____________.

8. Coating of _____________ is deposited on iron to protect it from corrosion.

9. What is LED

10. Define Electroplating

11. Name some materials around you which conduct electricity.

12. Name some materials around you which do not conduct electricity.

POLLUTION OF AIR AND WATER

Q.1 Fill in the blanks:-

(i) By volume about _______ of air is nitrogen and about _________ is oxygen.

(ii) Incomplete burning of fuels produces ________ which is a _______ gas.

(iii) Carbon monoxide _________ the oxygen carrying capacity of the blood.

(iv) Petroleum refineries are a major source of gaseous pollutants like ______ and ______.

(v) _______ used in refrigerators damages the ozone layer of the atmosphere.

(vi) Ozone layer protects us from the harmful ________ rays of the sun.

(vii) _______ of the world’s population is without safe drinking water.

(viii) We can save water by remembering the 3R’s ____, ____ and ________.

(ix) Acid rain is formed by the oxidation followed by dissolution of ________ and gases in rain water.

Q.2 MULTIPLE CHOISE QUESTIONS: (Choose the most appropriate answer.?

(A) Which of these causes water pollution?

  (a) Sewage (b) Industrial waste (c) Fertilizers and pesticides (d) All of these

(B) Which of these processes can not remove germs from water?

  (a) boiling (b) Filtration through Porous Pot (c) Reverse Osmosis (d) exposure to UV light

(C) Which of the following is not a pollutant unless present in excess?

  (a) Sulphur Dioxide (b) Carbon dioxide (c) Nitrogen dioxide (d) carbon monoxide

(D) Which of these can cause acid rain?

  (a) Sulphur Dioxide (b) Carbon dioxide (c) Nitrogen (d) carbon monoxide

Q.3 Define air pollution. What are air pollutants?

Q.4 What are the various sources of air pollutants?

Q.5 What is smog? Why is it harmful?

Q.6 What is acid rain?

Q.7 How is the Taj Mahal affected by air pollution?

Q.8 What is meant by ‘Marble Cancer’?

Q.9 Write the full forms (i) CFC (ii) CNG (iii) LPG (iv) WWF

Q.10 What is greenhouse effect? Name four greenhouse gases.

Q.11 Write a note on global warming mentioning its effects too.