State for each of the following whether it is due to evaporation or condensation:
(a) Water drops appear on the outer surface of a glass containing cold water.
(b) Steam rising from wet clothes while they are ironed.
(c) Fog appearing on a cold winter morning.
(d) Blackboard dries up after wiping it.
(e) Steam rising from a hot girdle when water is sprinkled on it.
(a) Condensation
Conversion of water vapours into the water droplets are known as condensation. When the cool water vapours of cold water comes in the contact of environment it becomes hot and convert into the water.
(b) Evaporation
It is because of the water converts into the vapours when hot iron is placed over them.
(c) Condensation
It is because of the conversion of vapours into tiny water droplets.
(d) Evaporation
It is due to evaporation, it mainly happens in high temperature faster.
(e) Evaporation
Due to cooling effect, here evaporation takes place.
How are clouds formed?
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?
When does a drought occur?
Which of the following statements are “true” ?
(a) Water vapour is present in air only during the monsoon. ( )
(b) Water evaporates into air from oceans, rivers and lakes but not from the soil.( )
(c) The process of water changing into its vapour, is called evaporation.( )
(d) The evaporation of water takes place only in sunlight.( )
(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.( )
To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet.
Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help? If yes, how?
Fill up the blanks in the following:
(a) The process of changing of water into its vapour is called _________________.
(b) The process of changing water vapour into water is called _________________.
(c) No rainfall for a year or more may lead to _________________ in that region.
(d) Excessive rains may cause _________________.
(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.
Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.
S.No. | Change | Can be reversed (Yes/ No) |
---|---|---|
1 | The sawing of a piece of wood | |
2 | The melting of ice candy | |
3 | Dissolving sugar in water | |
4 | The cooking of food | |
5 | The ripening of a mango | |
6 | Souring of milk |
Match the items in Column I with one or more items of Column II.
Column I Column II
Upper jaw have fins on the body
Fish has an outer skeleton
Ribs can fly in the air
Snail is an immovable joint
Cockroach protect the heart
shows very slow movement
have a streamlined body
Why does a lump of cotton wool shrink in water?
The distance between Radha's home and her school is 3250 m. Express this distance into km.
Give two examples each, of modes of transport used on land, water and air.
State whether the statements given below are True or False.
(i) Stone is transparent, while glass is opaque.
(ii) A notebook has lustre while eraser does not.
(iii) Chalk dissolves in water.
(iv) A piece of wood floats on water. (v) Sugar does not dissolve in water.
(vi) Oil mixes with water.
(vii) Sand settles down in water.
(viii) Vinegar dissolves in water.
Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.
Column I Column II
N - N _________
N - _________ Attraction
S - N _________
_________ - S Repulstion
How will you prove that air supports burning?
Why can a pace or a footstep not be used as a standard unit of length?
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.