The layer of air around the earth is known as ___________.
Atmosphere
Atmosphere may be defined as the layer of gases which contains oxygen, carbon dioxide, nitrogen and many other gases; dust particles and water vapours that are present around earth.
How will you prove that air supports burning?
How do plants and animals help each other in the exchange of gases in the atmosphere?
List five activities that are possible due to the presence of air.
How will you show that air is dissolved in water?
Why does a lump of cotton wool shrink in water?
What is the composition of air?
The component of air used by green plants to make their food, is ___________.
Which gas in the atmosphere is essential for respiration?
(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.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
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.
Name two foods each rich in:
(a) Fats
(b) Starch
(c) Dietary fibre
(d) Protein
Explain the process of making yarn from fibre.
Why do we need to separate different components of a mixture? Give two examples.
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?
Fill in the blanks.
(a) ______________ is caused by deficiency of Vitamin D.
(b) Deficiency of ______________ causes a disease known as beri-beri.
(c) Deficiency of Vitamin C causes a disease known as ______________.
(d) Night blindness is caused due to deficiency of ____________ in our food.
Fill in the blanks:
a) Plant fibres are obtained from_________ and ________ .
b) Animals fibres are __________ and ___________ .
State whether the following statements are true or false:
a) Yarn is made from fibres.
b) Spinning is a process of making fibres.
c) Jute is the outer covering of coconut.
d) The process of removing seed from cotton is called ginning.
e) Weaving of yarn makes a piece of fabric.
f) Silk fibre is obtained from the stem of a plant.
g) Polyester is a natural fibre.
Give two examples each, of modes of transport used on land, water and air.
What is a habitat?
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?