Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:
Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot
iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.
Opaque: A piece of rock, a CD, smoke, iron, an umbrella, a wall, a sheet of aluminium.
Transparent: Air, water, sheet of plane glass.
Translucent: A sheet of polythene, fog, a sheet of cellophone.
Luminous: A lightened fluorescent tube, flame of gas burner, a lighted torch, firefly, stove, sun, moon.
Non- luminous: A mirror, piece of rock, a wire mesh, iron, a wall.
Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?
In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
(a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw pictures of these.
To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Do you find that all living beings need the same kind of food?
Name the major nutrients in our food.
Classify the following fibres as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute
Name five objects which can be made from wood.
Why do we need to separate different components of a mixture? Give two examples.
Correct the following statements and rewrite them in your notebook.
(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of petals and sepals in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together.
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.
Fill in the blanks:
(a) Joints of the bones help in the ——————— of the body.
(b) A combination of bones and cartilages forms the _______ of the body.
(c) The bones at the elbow are joined by a ______________________ joint.
(d) The contraction of the _____________ pulls the bones during movement.
What is a habitat?
What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
When does a drought occur?
It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.
How are clouds formed?
Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.
Name five objects which can be made from wood.
Match the items given in Column A with that in Column B
Column A Column B
Milk, curd, paneer, ghee eat other animals
Spinach, cauliflower, carrot eat plants and plant products
Lions and tigers are vegetables
Herbivores are all animal products
What is the function of a stem in a plant?
Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why?