To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Yes, this change can be reversed. We usually shorten the length of our dress by folding it. It can be reversed by unfolding the length of the dress. So this change is an example of reversible changes.
A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?
A drawing sheet changes when you draw a picture on it. Can you reverse this change?
You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?
Give examples to explain the difference between changes that can or cannot be reversed.
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 |
(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.
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?
How is a compass used to find directions?
Write the names of the parts of a flower.
Fill up the blanks with the words given:
herbivore, plant, milk, sugarcane, carnivore
(a) Tiger is a ____________________ because it eats only meat.
(b) Deer eats only plant products and so, is called ______________.
(c) Parrot eats only _________________ products.
(d) The ________________ that we drink, which comes from cows, buffaloes and goats is an animal product.
(e) We get sugar from ___________________.
Explain, why speed is important for survival in the grasslands for animals that live there. (Hint: There are few trees or places for animals to hide in grasslands habitats.)
Arrange the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre,1 millimetre.
The distance between Radha's home and her school is 3250 m. Express this distance into km.
Write any two properties of a magnet.
How are cactus adapted to survive in a desert?
The component of air used by green plants to make their food, is ___________.
Classify the following fibres as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute