Textbook Solutions: Sorting Materials into Groups | Eureka Plus Class 6: Book Solutions, Notes & Worksheets PDF Download

I. Choose the correct option. 

II. Write one example for each of the following: 

1.
Ans:  Wood

2.
Ans:  Diamond

3.
Ans: Fiberglass

4.
Ans:  Copper

5.
Ans:  Silver

6.
Ans: Wood

7.
Ans: Lemon juice

III. Answer the following questions in one sentence. 

1.
Ans: Metals, plastics, ceramics.

2.
Ans: Density is the mass of an object divided by its volume.

3.
Ans: In a solid substance, molecules are tightly packed and have an orderly arrangement in some cases.

4.
Ans: Gas.

IV. Read and understand the given information

Some properties of matter depend on the way its molecules are arranged. If the molecules are closely packed then the matter is in its solid state. A solid is a good conductor of electricity if its molecules are arranged in orderly manner. To conduct electricity it is not enough that the molecules are arranged tightly.
The arrangement of molecules in two different solids is shown below.
Now, answer the questions. 
1.
Ans: Yes, the molecules in both solids A and B are arranged in an orderly manner.

2.
Ans: Solid A could be copper metal. This is because, in metals like copper, the molecules are closely packed together, which is characteristic of their ability to conduct electricity efficiently.

3.
Ans: Wood does not conduct electricity because it is an insulator. Its molecular structure does not allow the free movement of electrons, which is necessary for the conduction of electricity. Additionally, wood has a high resistance and lacks the free electrons or charge carriers that metals have, making it inefficient at conducting electricity.

V. Answer the following questions in three to four sentences. 

1.
Ans: A solution is formed when a substance (solvent) dissolves another substance (solute). For example, when salt (solute) is dissolved in water (solvent), it forms a salt solution, where the salt molecules are evenly distributed in the water, creating a homogeneous mixture.

2.
Ans: Soluble materials can dissolve in a particular solvent, while insoluble materials do not dissolve. Examples of soluble materials include sugar and salt, which dissolve in water. Examples of insoluble materials are sand and oil, which do not dissolve in water.

3.
Ans: Whether an object floats or sinks in water is determined by its density. Objects with a density less than that of water will float, while objects with a density greater than that of water will sink.

4.
Ans: This happens because smoke, which is produced when an incense stick is burnt, is in a gaseous state. Gases can spread throughout the available space, carrying the fragrance with them.

5.
Ans: Boats are made of wood because wood is less dense than water, allowing boats to float. Additionally, wood is a good material for boat construction due to its buoyant properties and durability in a water environment.

VI. Write a passage on each of the following topics.

Ans: 
Molecules and States of Matter:
Molecules are the fundamental building blocks of matter, combining atoms into various forms and structures. These molecules give rise to the different states of matter: solid, liquid, and gas. In a solid state, molecules are tightly packed and exhibit a fixed shape. Liquids have more freedom of movement, allowing them to flow and take the shape of their container. Gases, on the other hand, have molecules that move freely and independently. Understanding the behavior of molecules in these states is crucial in comprehending the physical properties of materials and their responses to temperature and pressure changes.
Good and Poor Conductors of Heat and Electricity:
The ability of materials to conduct heat and electricity is vital in numerous applications. Good conductors, like metals, efficiently transfer heat and allow the flow of electric current due to their abundance of free electrons. In contrast, poor conductors or insulators, such as rubber or wood, restrict the flow of heat and electricity. This dichotomy plays a pivotal role in designing efficient electrical circuits and thermal systems, influencing everyday technologies and industrial processes. The understanding of conductive properties aids in the development of materials tailored for specific purposes, balancing conductivity and insulation as needed.
Importance of Sorting Things into Groups:
Sorting is a fundamental cognitive process that helps us make sense of the world and manage information efficiently. By grouping similar items based on shared characteristics or properties, we create a systematic and organized structure. This process simplifies decision-making, problem-solving, and information retrieval. In scientific endeavors, classification into groups facilitates the study of diverse organisms or materials, enabling scientists to identify patterns and draw meaningful conclusions. In daily life, sorting aids in tasks ranging from organizing belongings to streamlining complex information. It fosters clarity, enhances productivity, and is a fundamental aspect of human cognition, contributing to effective learning and problem-solving skills.

Think and answer

II. Given below are pairs of objects used in everyday life. Consider the properties of the materials and conclude which is a better option in each. 
1.
Ans: Ceramic cup, as it is a poor conductor of heat and will not become too hot to handle when filled with hot milk.

2.
Ans: Cloth bag, as it is more environmentally friendly and can be reused, reducing plastic waste.

3.
Ans: Wooden grill, as it is a poor conductor of heat and will not become excessively hot in the sun, making it safer.

4.
Ans: Thin paper, as it is lighter and will make the kite easier to fly.