The two ways to identify the magnet are
(i) Hang the metal bars with a thread and having its level horizontal one by one and let it stop in any direction. Now, if we move it by"pushing it slowly and it returns to the same direction, it means that it is a magnet otherwise it is an iron bar simply.
(ii) Take some iron filings and move the iron bars over these iron filings one by one. If iron filings are attracted very strongly at poles, then it is a magnet and if it is not attracted, then it is simply an iron bar.

Plastic bags are not considered suitable for storing cooked food because
(i) these bags may have been used earlier for some other purposes. The residue left behind can be harmful.
(ii) food can mix with chemicals present in plastic bags.
(iii) sometimes bags collected by rag pickers are washed and used which is not a healthy practice.
(iv) plastic bags are not recommended for recycle and reuse as it can harm our health.

(i) Powder container The elongated metallic powder container can be used as pen-pencil stand or to grow money plant, etc. The plastic containers should be sent to plastic industries for recycling.
(ii) Cold drink cans For storing liquids, growing herbaceous plants like tulsi, money plant, small flowering plants.
(iii) Plastic bottles These can also be used for growing plants, storing liquids, etc.
(iv) Shoe box For making small red cross box, storing pen-pencils and other small articles.

The manure produced from vermicomposting is of high quality Vermicompost is better because
(i) it is cheap and easy to produce while chemical fertilisers are very expensive.
(ii) vermicompost is a natural manure which does not harm the soil or the plants they are added to while chemical fertilisers have adverse effect on both.

A moving car though moves is not considered as a living organism because of the following reasons:
(i) Living organisms have the ability to move on their own, whereas a car moves by the burning of fuels like diesel and petrol.
(ii) Like all living organisms, a car does not show any other living characteristics like respiration, digestion, reproduction or growth.

(a) The plant responded to the stimuli of light. Since, light was coming through window so, plant grew towards that direction.
(b) (i) Yes, all living things responds to changes around them. These changes are called stimulus and our reaction towards them is response.
(ii) Folding/Closing of 'touch-me-not' plant leaves when someone touches its leaves closing of eyes due to sudden bright light
(c) She is careful, responsible and observant. She is also curious about unique behaviours and has an inquistive/enquiring nature.

Sometimes, the shadow of the object (ball) may not be formed because of improper arrangement. It may be that the direction of the torchlight is not towards the screen. The shadow will be formed only if screen, torch and ball are in the same straight line (as shown in figure).

The process by which land water returns back to a sea or an ocean is as follows:
(i) Snow/Rain falling on the mountains melts into water that flows down in the form of streams and rivers.
(ii) A part of the rainwater gets absorbed into the ground and rest also flow in the form of stream or rivers.
(iii) The river water after passing through various regions ultimately reaches into a sea or an ocean

Elastic tapes are stretchable due to which their length can be increased during the measurement if it is not handle with care. Therefore, the measurement done by elastic tapes may be greater than the actual length of the object. So, we can say that elastic tapes are not accurate to measure a length.

We can differentiate these materials on the basis of lustre, hardness, softness, roughness or smoothness. 

Oxygen gas dissolves in water, i.e. oxygen gas is soluble in water. The plants and animals which live in water use the oxygen dissolved in water for respiration. Thus, oxygen gas dissolved in water is very important for the survival of animals and plants that live in water.

(a) No, the anklets were made of pure silver.
(b) Silver anklets lost their lustre and appear dull, because of the action of air and moisture on them.
(c) Kavita's mother is knowledgeable and intelligent.

Changes that can be reversed are called reversible changes.
Some examples are as follows:
(i) Melting of wax
(ii) Folding of a paper
(iii) Knitting of a sweater
(iv) Inflating of a tyre

(a) Sarita can follow the following steps:
(i) Collect plant twig with flowers.
(ii) Press the8m in papers/magazines.
(iii) Change the paper/magazine every day for 5-6 days.
(iv) When plants are well pressed and dried place them on white plane paper sheet.
(v) Stick the plants to sheet with cello tape.
(vi) Try to identify the plant.
(vii) Take help of teachers/seniors for plant identification.
(b) Yes, plants can also be identified on the basis of the nature of their stem and size.
(c) Inquisitive, scientific attitude and love for nature.

Cotton is the most important of all plant fibres, used to make clothes.Cotton shirt can be prepared by following steps:
Cotton bolls \(\underset { \xrightarrow{}}{ Ginning } \) Cotton fibre \(\underset { \xrightarrow{}}{ Spinning } \) Cotton yarn \(\underset { \xrightarrow{}}{ Weaving} \) Cotton fabric \(\underset { \xrightarrow{}}{ sewing} \) Cotton shirt
The making of cotton shirt is a long process. From cotton bolls, cotton is usually picked by hand. Fibres are then separated from the seeds by combing. This process is called ginning.
In spinning process, the fibres from a mass of cotton wool are drawn out and twisted. This brings the fibres together to form a yarn.
Weaving is binding of two sets of yarns at right angles to make a fabric. Weaving is done on looms. Now, on sewing this cotton fabric by needle, we get the cotton shirt.

(a) The process of separation of the lighter particles of a solid from a liquid is known as Churning. It is also known as centrifugation.
(b) The purpose of churning is to remove butter or cream from the curd or milk. So in lassi, there is a less fat content as compared to milk.
(c) Ashraf is curious, scientific and intelligent boy.

Paheli can make this water fit for drinking by work on following sequence:
Filtration using muslin cloth (cotton fabric).
                         \(\downarrow\)
Swirl with alum and leave water undisturbed for some time.
                          \(\downarrow\)
The clear liquid above the impurities is poured in another container(decantation).
                           \(\downarrow\)
Boil for 10 min in covered pan with lid.
                           \(\downarrow\)
Cool, filter and now, it is fit for drinking.

(a) The main sources of calcium minerals are milk, cheese, eggs and green vegetables. It also found in flour and bread.
It helps in formation of bone, teeth and blood clotting.
(b) Magnesium is found in cheese, green vegetable, bread and fish.
It helps in energy transfer and muscles activity. It works with calcium and vitamin-C.
(c) Potassium is found in meat, fruit, eggs, milk, etc.
The main function of potassium is balance in tissue fluid and blood. It also helps in nerve impulse conduction.
(d) Zinc is mainly found in onions, liver and green vegetables.
It works as a enzyme activator in our body.
(e) Iron is found in green vegetables, fresh fruits, etc.
Iron is needed to make haemoglobin present in red blood cells which carry oxygen from the lungs to the body parts.

(a) Boojho is suffering from night blindness.
(b) The food component which may be lacking in his diet is vitamin-A.
(c) The food items that he should include in his diet to overcome the deficiency of vitamin are carrot, papaya, milk, mango and fish oil.

(a) The insect is 'honeybee'. Its place is 'beehive'.
(b) This insect feeds on pollens and nectar of flowers.
(c) Honeybee visits the flowers and it brings about pollination while collecting its food, thus helps the farmers, setting is facilitated.
(d) We collect honey from beehive.
(e) Honey is rich in sugars, enzymes and minerals. We use it as a food.