Class 6 Ques ans

 Chapter 1 food:- Where does it come from?

Q. 1. Do you find that all living beings need the same kind of food?
Ans. No, all living beings do not need same kind of food.

Q.2. Name five plants and their parts that we eat.
Ans. The names of five plants and their parts that we eat are:
(i) Paddy: seeds
(ii) Wheat: seeds
(iii) Mustard plant: seeds and leaves
(iv) Brinjal plant: fruits
(v) Potato plant: stems

Chapter 3:- " Fibre to fabric"

Q. 4. From which part of the plant cotton and jute are obtained?
Ans.
(i) Cotton – Cotton bolls (from the surface of cotton seeds) (fruit)
(ii) Jute – Stem

Q.5. Name two items that are made from coconut fibre.  
Ans.
(i) Ropes
(ii) Mats

Q.6. Explain the process of making yarn from fibre.
Ans. Yarns are made up of thin strands called fibres. The process of making yam from fibres is called spinning. In this process, a mass of cotton wool are drawn out and twisted. This brings the fibres together to form yarn.

Chapter 5 seperation of substances

1. Why do we need to separate different components of a mixture? Give two examples. 

Ans: Among different components of mixture there are many substances which are harmful or not useful for us. To remove these harmful or unuseful components we need to separate them. For example:

(a) Tea leaves are separated from the liquid with a strainer while preparing tea.

(b) Stone pieces from wheat, rice or pulses are picked out by hand.

2. What is winnowing? Where is it used?

Ans: Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. This process is used by farmers to separate lighter husk particles from heavier seeds of grain.

3.3.H will you separate husk or dirt particles from a given sample of pulses before cooking?

Ans: Husk or dirt particles can be separated by winnowing, being lighter they wall fly away from pulses.

4. What is Sieving? Where can it be used?

Ans. Sieving is a process by which fine particles are separated from bigger particles by using a sieve. It is used in flour mill or at construction sites. In flour mill, impurities like husks and stones are removed from wheat. Pebbles and stones are removed from sand by sieving

5.How will you separate sand and water from their mixture?

Ans. We will separate sand and water by sedimentation and decantation method. First we leave this mixture for some time. After some time, the sand which is; heavier is settled down at the bottom. After that we wall pour water into another container and the mixture will be separated.

6. Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?

Ans. Sugar can be separated from wheat flour by sieving. Due to difference in the size of particles, sugar will stay on sieve and wheat flour will pass through it.

7. How would you obtain clear water from a sample of muddy water?

Ans. We will obtain clear water from a sample of muddy water by the process of filtration.

10. Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add ice to the lemonade before or after dissolving sugar ? In which case would it be possible to dissolve more sugar ?

Ans. We should add ice after dissolving sugar. When the temperature is high then more sugar can be dissolved. After mixing ice it gets cool and less sugar will dissolve in it.

Chapter 5 "Seperation of Substances"

1. Why do we need to separate different components of a mixture? Give two examples. 

Ans: Among different components of mixture there are many substances which are harmful or not useful for us. To remove these harmful or unuseful components we need to separate them. For example:

(a) Tea leaves are separated from the liquid with a strainer while preparing tea.

(b) Stone pieces from wheat, rice or pulses are picked out by hand.

2. What is winnowing? Where is it used?

Ans: Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. This process is used by farmers to separate lighter husk particles from heavier seeds of grain.

How will you separate husk or dirt particles from a given sample of pulses before cooking?

Ans: Husk or dirt particles can be separated by winnowing, being lighter they wall fly away from pulses.

4. What is Sieving? Where can it be used?

Ans. Sieving is a process by which fine particles are separated from bigger particles by using a sieve. It is used in flour mill or at construction sites. In flour mill, impurities like husks and stones are removed from wheat. Pebbles and stones are removed from sand by sieving

. How will you separate sand and water from their mixture?

Ans. We will separate sand and water by sedimentation and decantation method. First we leave this mixture for some time. After some time, the sand which is; heavier is settled down at the bottom. After that we wall pour water into another container and the mixture will be separated.

Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?

Ans. Sugar can be separated from wheat flour by sieving. Due to difference in the size of particles, sugar will stay on sieve and wheat flour will pass through it.

7. How would you obtain clear water from a sample of muddy water?

Ans. We will obtain clear water from a sample of muddy water by the process of filtration.

. Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add ice to the lemonade before or after dissolving sugar ? In which case would it be possible to dissolve more sugar ?

Ans. We should add ice after dissolving sugar. When the temperature is high then more sugar can be dissolved. After mixing ice it gets cool and less sugar will dissolve in it.

Chap 10 "Motion and measurement of distances"

Give two examples each of modes of transport used on land, water and air.

Ans:

(i) Land—Bus, truck, train.

(ii) Water—Ship, boat.

(iii) Air—Aeroplane, Helicopter.

Why can a pace or a footstep not be used as a standard unit of length?

Ans: Because a pace or a footstep of each and every person is not equal.

5. The height of a person is 1.65 m. Express it in cm and mm.

Ans:

(a) 1.65 m, as one metre = 100 cm

= 1.65 x 100 cm = 165 cm

(b)65 x 100 x 10 mm = 1650 mm.

6. The distance between Radha’s home and her school is 3250 ,m. Express this distance in km.

Ans: 

7. While measuring the length of a knitting needle, the reading of the scale at one  end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?

Ans:  Length of the needle = 33.1 cm – 3.0 cm = 30.1 cm.

8. Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.

Ans: 

(i) Similarity: Both the wheel of a bicycle and a ceiling fan exhibit motion on a fixed axis.

(ii) Dissimilarity: Bicycle moves forward thus executes rectilinear motion but fan does not show such motion.

Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?

Ans:  An elastic measuring tape gives incorrect length of the distance between two points.

Reasons:

(i) The length of the elastic tape varies and depends upon the force by which it is stretched.

(ii) Measurement would vary between 2 or 3 readings even when measured by the same person and by the same elastic tape.

(iii) Measurement would also vary if different persons measure the same distance.

10. Give two examples of periodic motion.

Ans:

(i) Oscillations of a pendulum.

(ii) Motion of swing/motion of earth round the sun.