CBSE Class 7 Science Sample Paper Set K

CBSE Class 7 Science Sample Paper Set K. It’s always recommended to practice as many CBSE sample papers as possible before the examinations. The latest sample papers have been designed as per the latest blue prints, syllabus and examination trends. Sample papers should be practiced in examination condition at home or school and also show it to your teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.

1 Name the largest gland in the human body. 

Ans. Liver is the largest gland in the human body.

2 Define temperature. 

The degree of hotness and cold ness of a substance is known as temperature.

3 State the nature of image formed by a concave and a convex mirror. 

The nature of image formed by a concave mirror is real and inverted and by a convex mirror is virtual and erect.

4 Which part of alimentary canal is involved in:

The part of alimentary canal is involved in:

a] killing of bacteria-stomach

b] formation of faeces-large intestine

a] killing of bacteria b] formation of faeces

5 Differentiate between a wool fibre and a silk fibre. (2 points) 

                        WOOL                                       SILK

Wool does not have shiny appearance .It is   Silk has shiny appearance. It is lustrous.

not lustrous.

Wool is better insulator of heat.                  Silk is not good as wool in retaining warmth.

6 a] Identify the chemicals:

i] I am red in colour and obtained from lichens. When I am mixed with soap solution, I change my colour.

ii] I am found in lemon and orange. When I mix with blue litmus, I change its colour to red.

iii] I am one of the most commonly used chemical and my colour is white. I can bet that you use me every day in your food in your life.

Ans. a] The chemicals are:

i]Red litmus.

ii] Blue litmus.

iii] Salt

OR

b] Steps are:

1. Take a test tube fill one fourth of test tube with hydrochloric acid(HCl).

2. Add few drops of phenolphthalein indicator.

3. To this add sodium hydroxide drop by drop till the pink colour appears.

4. Now add one drop of HCl again . The solution again became colourless.

5. Again add one drop of sodium hydroxide. The solution again became pink. It is evident that when a solution is basic phenolphthalein gives pink colour and when it is acidic it changes to colourless.

6. When an acidic solution and basic solution are mixed in suitable amount , both the solutions are neutralized. The acidic nature and basic nature are destroyed. The resulting solution is neither acidic nor basic it is neutral and the process is neutralization.

7 State the laws of reflection demonstrated by the given figure.

Ans The laws of reflection are:

1.Angle of incidence is equal to angle of reflection

2.The incident ray, reflected ray and the normal at the point of incidence all lie on same plane.

8 Differentiate between physical and chemical changes. (3 points) 3

Ans.              PHYSICAL CHANGE                 CHEMICAL CHANGE

A new substance is not formed               A new substance is formed

Temporary changes                                     Permanent changes

Mostly irreversible                                      Mostly reversible

9 Name any three diseases caused by stagnant water.

OR

What role you can play as an active citizen in relation to sanitation.

Ans. Three diseases caused by stagnant water are-cholera, dysentery and typhoid.

OR

We can do following things as an active citizen in relation to sanitation(any three points):

1. Used oils and fats should not be thrown in the drains

2. We should cover open drains

3. We should never urinate on the road side

4. Non biodegradable waste should be disposed off properly

10 Explain the lifecycle of a female silk moth. 3

Ans. 1.The female silk moth lays eggs, from which hatch larvae which are called caterpillars or caterpillars silkworms. silkworms

2.They grow in size and when the caterpillar is ready to enter the next stage of its life history called pupa, it pupa first weaves a net to hold itself.

3.Then it swings its head from side to side in the form of the figure of eight (8).

4.During these movements of the head, the caterpillar secretes fibre made of a protein which hardens on exposure to protein air and becomes silk fibre.

5. Soon the caterpillar completely covers itself by silk fibres. This covering is known as cocoon.

6. The further development of the cocoon moth continues inside the cocoon and it changes into moth. Silk fibres are used for weaving silk cloth

11 Explain the phrase – ‘Unity is strength’ on the basis of making fabric from fibre. 3

Ans. Unity is strength is a proverb that means sticking together is a source of strength.

It is related with the making of fabric from fiber because to produce a fabric more fiber should be used in unity for producing a lasting cloth.

12 Identify the plant and explain its mode of nutrition.

Ans. The plant is pitcher plant and its mode of nutrition is insectivorous plant.

The pitcher-like structure is the modified part of the leaf. The apex of the leaf forms a lid which can open and close the mouth of the pitcher. Inside the pitcher there are hair which are directed downwards. When an insect lands in the pitcher, the lid closes and the trapped insect gets entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher. Such insect-eating plants are called insectivorous plants.

13 Differentiate between aerobic and anaerobic respiration. (3 points)

         AEROBIC RESPIRATION                      ANAEROBIC RESPIRATION

It takes place in presence of oxygen.    It takes place in absence or lack of oxygen.

More energy is released.                                Less energy is released.

Complete oxidation of glucose.                  Incomplete oxidation of glucose.

14 Paraphrase the use of vermi-processing toilets.

14 A design of a toilet in which humans excreta is treated by earthworms has been tested in India. It has been found to be a novel, low water-use toilet for safe processing of human waste. The operation of the toilet is very simple and hygienic. The human excreta is completely converted to vermi cakes — a resource much needed for soil.

15 Differentiate between milk teeth and permanent teeth. (3 points) 3

16 Imagine you are an acid. Now answer the following questions:

a] How are you different from a base?

b] When you react with a base, what are the products formed?

c] Why can’t you be stored in metal containers?

17 Describe the conditions necessary for photosynthesis and also write the equation representing the process

17 The conditions necessary for photosynthesis are-

Carbon di oxide- leaves. Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. These pores are surrounded by ‘guard cells’. Such pores are called stomata.

Water- Water and minerals are transported to the leaves by the vessels which run like pipes throughout the root, the stem, the branches and the leaves. They form a continuous path or passage for the nutrients to reach the leaf. The vessels that transport water and minerals are called xylem and that transport food from leaf is phloem.

Chlorophyll- The leaves have a green pigment green pigment called chlorophyll.

chlorophyll It helps leaves to capture the energy of the sunlight.

Sunlight-The ultimate source of energy. This energy is used to synthesize (prepare) food from carbon dioxide and water. Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis ( photosynthesis Photo: light; synthesis : to combine).

The equation representing the process-

18 A] a) Differentiate between clinical and laboratory thermometer. (3 points)

b) Give reason for the following:

i] Cooking utensils are made up of metals.

ii] Pressure cookers are provided with plastic handle.

B] a) Write an activity to show that solids transfer heat by conduction.

b) A person has a white shirt and a black shirt. Which shirt will make him more comfortable in winter and which one in summers? Give reason for your answer.

18 A] a)

CLINICAL THERMOMETER                   LABORATORY THERMOMETER

Range is 35 to 45 degree Celsius      Range is -10 to 110 degree Celsius

Kink is there.                                             Kink is not there.

It is shorter than laboratory thermometer.   It is longer than laboratory thermometer.

b) i] Cooking utensils are made up of metals as metals are conductor of heat.

ii] Pressure cookers are provided with plastic handle as plastic is a bad conductor of heat.

OR

B] a) Take a rod or flat strip of a metal, say of aluminum or iron. Fix a few small wax pieces on the rod. These pieces should be at nearly equal distances .Clamp the rod to a stand. If you do not find a stand, you can put one end of the rod in between bricks. Now, heat the other end of the rod and observe. You will observe that wax melted one by one and pieces fell one by one. This is because the heat has transferred from one particle to another. This mode of transfer of heat in solids is known as conduction.

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