Science Answer The Following Questions In Short.[2 Marks Each]

Dividing materials into groups makes it easy to study their properties. It also helps to observe any pattern in these properties. For example: by placing similar types of objects together, we can locate them easily.

The grouping of objects in proper way makes it easier to work. When we go to purchase some things, the shopkeeper locates it easily, because there are separate shelves to put various items and similar things are kept at one place. If he randomly places all of these, he would never be able to find them so quickly and easily.

1. Eatables: Water, orange, sugar and apple.
2. Non-eatables: Basket ball, globe and earthen pitcher.

1. Table.
2. Chair.
3. Doors.
4. Boat.
5. Bed.

Grouping the objects helps us to arrange them in a systematic manner. The objects when grouped are easy to handle. When grouped, it is easy to know the properties of an object clearly. Grouping also makes easy to compare two objects.

Take six test tubes, fill each of them about half with water. Keep each of them in a test tube stand. Add a pinch of each of six substances in separate test tubes. Shake well and allow to stand for few minutes. Common salt, sugar and washing soda dissolve while iodine, chalk powder and sand do not dissolve.

Float in water: Leaf, paper.
Sink in water: Key, apple and stone.

When little amount of starch is added it will dissolve in water. But as the amount of starch increases, the solution starts thickening and forms a suspension.

Materials are classified into different groups for the following reasons:

1. For the convenience of identifying and locating the different materials.
2. To study their properties and identify common patterns among them.

An object will only float if its density is less than that of the surrounding liquid. It will sink if its density is greater than that of the surrounding liquid.

Water soluble substances: Salt, sugar.
Water insoluble substances: Sand, paint, chilli powder, desi ghee, blotting paper.

Raveena has got a solution because honey will dissolve in water whereas red chilli powder, butter and petrol float on water.

Those substances or material, through which things can be seen are called transparent. For example-water, glass etc. The materials through which objects can be seen but not clearly are known as translucent. For example-oily patch on paper, butter paper.

• Mercury is liquid at room temperature.
• It is a good conductor of heat.
• Mercury has lustre, so, it is easy to read the temperature shown by the level of mercury.