Class 8 Science - Chapter Stars and The Solar System NCERT Solutions | In which part of the sky can you find Ve

What is a constellation? Name any two constellations.

Explain how you can locate the Pole Star with the help of Ursa Major.

Boojho made the following sketch (Fig. 17.29) of the solar system. Is the sketch correct? If not, correct it.

Draw sketches to show the relative positions of prominent stars in
(a) Ursa Major and (b) Orion

Name two objects other than planets which are members of the solar system.

Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?

The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accomodate?

Phases of the moon occur because

(a) we can see only that part of the moon which reflects light towards us.
(b) our distance from the moon keeps changing.
(c) the shadow of the Earth covers only a part of moon’s surface.
(d) the thickness of the moon’s atmosphere is not constant.

Do all the stars in the sky move? Explain.

Mark the following statements as true (T) or false (F):
(a) Pole Star is a member of the solar system. ( )
(b) Mercury is the smallest planet of the solar system. ( )
(c) Uranus is the farthest planet in the solar system. ( )
(d) INSAT is an artificial satellite. ( )
(e) There are nine planets in the solar system. ( )
(f) Constellation Orion can be seen only with a telescope. ( )

Which of the following can be beaten into thin sheets?
  (a) Zinc     (b) Phosphorus     (c) Sulphur     (d) Oxygen

Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called .

Give two examples each of situations in which you push or pull to change the state of motion of objects.

Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces.                                                                                                                                                                      (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction.

List conditions under which combustion can take place.

Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)

Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth.

Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called                  .
(b) Species found only in a particular area is known as                          .
(c) Migratory birds fly to far away places because of                     changes.

Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.

What are the different ways in which water gets contaminated ?

Categorise the materials of the following products into ‘can be recycled’ and ‘cannot be recycled’:

Telephone instruments, plastic toys, cooker handles, carry bags, ball point pens, plastic bowls, plastic covering on electrical wires, plastic chairs, electrical switches.

Describe the construction of a kaleidoscope.

Explain why plastic containers are favoured for storing food.

Explain why the following are made of thermosetting plastics.
(a) Saucepan handles
(b) Electric plugs/switches/plug boards

Explain circumstances leading to acid rain. How does acid rain affect us?

Which of the following is not a greenhouse gas?
(a) Carbon dioxide
(b) Sulphur dioxide                                                                                                                                                                                                                                  (c) Methane
(d Nitrogen

Complete the following word puzzle with the help of clues given below. 

Down
1. Providing water to the crops.
2. Keeping crop grains for a long time under proper conditions.
5. Certain plants of the same kind grown on a large scale.

Across
3. A machine used for cutting the matured crop.
4. A rabi crop that is also one of the pulses.
6. A process of separating the grain from chaff.

Mark (✓) the correct answer:

Rayon is different from synthetic fibres because
(a) it has a silk like appearance
(b) it is obtained from wood pulp
(c) its fibres can also be woven like those of natural fibres

Explain why some fibres are called synthetic.

In the following Table some substances are given in Column I. In Column II some uses are given. Match the items in column I with those in Column II.