Class 6 Science Chapter 4 Important Questions

Class 6 Science Chapter 4 Important Questions of Sorting Materials into Group with keywords and complete explanation. We are trying to provide the collection of Class 6 Science Chapter 4 Extra Questions which are important for all exams Class 6 Science session 2020-21.

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Class 6 Science Chapter 4 Important Questions 2020-21

Class:6
Subject:Science
Contents:Important Questions & Keywords

Class 6 Science Chapter 4 Extra Questions 2020-21

Class 6 Science Chapter 4 Important Questions for extra practice and keywords explanation updated for new academic session 2020-21. These Class 6 Science Chapter 4 Extra Questions covers all the keywords given in NCERT Books. These practice questions are important for class 7 science class test as well as school exams.

6th Science Chapter 4 Important Questions Set – 1

How does sorting of materials help us? Discuss.

It helps to collecting information and gaining systematic knowledge of things as possible. It helps in dividing materials in groups makes it convenient to study their properties. It is convenient to work with all materials or members of a group after knowing their properties.

Name some objects which we see around us.

We see around us, chair, bullock cart, cycle, cooking utensils, books, clothes, toys, water, stones and many other objects.

Can you write the name of some plastic and wooden objects?

Objects that are made of plastics such as buckets, lunch boxes, toys, water containers, pipes and many objects. Objects that are made of wood such as chair, table, plough, bullock cart and its wheels, matchbox, and many objects.

Write down the different types of objects that are made from the same material.

All objects around us are made of one or more materials. These materials may be chair, table, plough, bullock cart and its wheels. All objects are made up of wood. And books, notebooks, newspaper, toys, calendars are made up of paper.

Appearance of an Objects

Generally, appearance deals with lustre, looks, colour, shape, state of the objects. Materials usually look different from each other. Wood looks very different from iron. Iron appears different from copper or aluminium. At the same time, there may be some similarities between iron, copper and aluminium that are not there in wood.

6th Science Chapter 4 Important Questions Set – 2

How would you separate some materials? Write the ways you know.

First, we grouped objects in many different ways. We then found that objects around us are made of different materials. At times, an object is made of a single material. An object could also be made of many materials. And then again, one material could be used for making many different objects.

Why does a tumbler not make with a piece of cloth?

We should keep in mind that we generally use a tumbler to keep a liquid. Therefore, it would be silly, if we were to make a tumbler out of cloth. We need for a tumbler is glass, plastics, metal or other such material that will hold water.

How does appearance of objects help us to make sort out of different materials? Show with an activity.

Collect small pieces of different materials – paper, cardboard, wood, copper wire, aluminium sheet, chalk. Separate the shiny materials into a group. Now, cuts each material into two pieces and look at the freshly cut surface. Some of these materials are appear shiny. Include these objects also in the group of shiny materials. Instead of cutting, you can rub the surface of material with sand paper to see if it has lustre. Materials that have such lustre are usually metals. Iron, copper, aluminium and gold are examples of metals. Therefore, we can differentiate the materials, according to the lustre.

According to the property of hardness, how would you differentiate whether the object is soft or hard? Justify your answer.

When you press different materials with your hands, some of them may be hard to compress while others can be easily compressed. Take a metal key and try to scratch with it, the surface of a piece of wood, aluminium, a piece of stone, a nail, candle, chalk, any other material or object. You can easily scratch some materials, while some cannot be scratched so easily. Materials which can be compressed or scratched easily are called “soft” while some other materials which are difficult to compress are called “hard”. For example, cotton or sponge is soft while iron is hard.

Soluble and Insoluble

Soluble: Some substances have completely disappeared or dissolved in water. These substances are termed as Soluble.
Insoluble: Substances do not mix with water and do not disappear even after we stir for a long time. These substances are termed as Insoluble.

6th Science Chapter 4 Important Questions Set – 3
Name the component which is known as Universal Solvent?

Water which is known as “universal solvent” as it can dissolve maximum materials.

“A gas dissolved in water is very important for the survival of animals and plants that live in water”. Write the name of the gas.

The name of the gas is oxygen which dissolved in water and very important for the survival of animals and plants that live in water.

Write down the five examples of each objects that float and sink in water.

Objects that float in water: plastic, wood, oil, sponge, petrol, kerosene, wax, ships etc.
Objects that sink in water: rock, marble, steel, iron, copper, nickel, sand, mercury etc.

What is “transparent”? Give one example where transparent materials of containers are used.

Transparent: Those substances or materials, through which things can be seen, are called transparent. Glass, water, air and some plastics are examples of transparent materials.
Shopkeepers usually prefer to keep biscuits, sweets and other eatables in transparent containers of glass or plastic, so that buyers can easily see these items.

Uses of Oxygen Gas

Oxygen gas constitutes 20.8% of the Earth’s atmosphere. Oxygen is used by animals and plants in the respiration (breathing) process. Tanks of oxygen are used in medicine to treat people with breathing problems. They are also used as life support for astronauts and scuba divers. The majority of the oxygen used in industry is used in the manufacturing of steel.

6th Science Chapter 4 Important Questions Set – 4
With the help of an activity, Boojho wants to know about translucent material. Can you help him?

Take a sheet of paper and look through it towards a lighted bulb. Now, put 2-3 drops of some oil and spread it on the sheet of paper. Look again towards the lighted bulb through that portion of the paper on which the oil has been spread. You will be find that the bulb is more clearly visible than before. But, not clearly through the oiled paper.
Generally, the materials through which objects can be seen, but not clearly, are known as translucent material.

There are some materials given below. Paheli wants to make a group material as Opaque, Transparent and Translucent. Card-board, Air, Bricks, Water, Frosted glass, Plywood, Oily paper, Mirror, Polyethene, Stone, Glass.

Opaque: Card-board, Bricks, Plywood, Mirror, Stone.

Transparent: Air, Water, Glass

Translucent: Oily paper, Polyethene, Frosted glass.

“In everyday life, we often group materials for our convenience”. Justify the statement.

As we know that in everyday life, we often group materials for our convenience. At home, we usually store things in such a manner that similar objects are placed together. Such an arrangement helps us to locate them easily.
Similarly, a grocer usually keeps all type of biscuits at one corner of his shop, all soaps at another while grains and pulses are stored at some other place. Materials differ in their appearance and the way they mix in water or other liquids. They may float or sink in water or may be transparent, opaque or translucent. Materials can be grouped on the basis of similarities or differences in their properties.
There is another reason why we find such grouping useful as dividing materials in groups makes it convenient to study their properties and also observe any patterns in these properties.

Paheli wants to know, why some metals lost their shine and appear dull?

Some metals often lose their shine and appear dull, because of the action of air and moisture on them.
Some metals as a result of oxidation with the atmospheric oxygen form oxides and by which their appearance becomes dull.

Opaque Materials

Opaque: There are some materials through which you are not able to see. These materials are called opaque.
Wood, cardboard and metals, are examples of opaque materials.

6th Science Chapter 4 Important Questions Set – 5
Given below are the names of some objects and materials: Water, basket-ball, orange, sugar, globe, apple and earthen pitcher. Group them as: a)Round shaped and other shapes. b)Eatable and non-eatables.

(a)
Round shape: basketball, orange, globe, apple, earthen pitcher
Other shape: Water, sugar
(b)
Eatable: Water, orange, sugar, apple
Non-eatable: Basket-ball, globe and earthen pitcher

Why do you think oxygen dissolve in water is important for the survival of aquatic animals and plants?

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.

Take a small cotton ball and place it in a tumbler bowl filled with water. Observe it for at least 10 minutes. Will it float or sink in water and why?

Cotton ball initially floats on water but after few minutes (i.e. 10 min. to 15 min.), its sinks because it absorbs water.

“If you are playing hide and seek, you will choose an opaque place to hide”. Justify your answer.

Generally, when we are playing hide and seek, we choose an opaque place to hide because an opaque material does not allow light to pass through them due to which the object or person behind them cannot be seen.
If we choose transparent materials to hide, person can be seen easily because transparent materials, allow almost all the light to pass through them. Therefore, in the hide and seek game we would always prefer to choose an opaque place to hide.

Items that Float on Water

Wooden block, paper, balloon, hair, plastic bottle, wooden logs, boat etc. will float on water. A few of these like hair, balloon, can float on kerosene oil. Generally, substance have less density than oil and water can float.
For example, few types of wood have density higher than oil but less than water so it floats on water but not in kerosene.

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