NCERT Solutions of Class 9 Science Book Chapter Brief

Chapter 1: Matter in Our Surrounding

The Class 9 science textbook starts with the chapter “Matter in Our Surroundings”. Everything that we see around us is made up of material which is called matter. These things occupy space and have mass. Earlier, Indian philosophers had classified matter into 5 basic elements called Panch Tatva – air, water, earth, sky and fire. Now, modern scientists have come up with 2 types of classification, i.e., based on physical property and chemical nature. In this chapter, students will learn about the physical properties of matter.

The matter is made up of particles and these particulars are very small. The particles of matter have space between them, they are continuously moving and attract each other. The matter around us exists in 3 different states – solids, liquids and gases. These states of matter arise due to variation in the characteristic of the particles of matter. All the 3 states of matters have been explained in-depth with the help of activities. 

Further, the textbook explains that the state of matter is inter-convertible. The state of matter can be changed by changing temperature or pressure. The phenomenon of change of a liquid into vapour at any temperature below its boiling point is called evaporation. The rate of evaporation depends upon the surface area exposed to the atmosphere, the temperature, the humidity and the wind speed. Evaporation also causes cooling.

Topics Covered in Class 9 Science Chapter 1 Matter in Our Surrounding :

Definition of matter; solid, liquid and gas; characteristics – shape, volume, density; change of state –  melting (absorption of heat), freezing, evaporation (cooling by evaporation), condensation, sublimation.

Chapter 2: Is Matter Around Us Pure?

This chapter of NCERT Class 9 Science students will teach about mixtures, solutions, properties of solutions, separation of mixtures, and physical and chemical changes. Along with this, they will also learn about compounds and their properties, the difference between mixtures and compounds, the classification of matter, etc.

Topics Covered in Class 9 Science Chapter 2 Is Matter Around Us Pure?  :

Nature of matter: Elements, compounds and mixtures. Heterogeneous and homogenous mixtures, colloids and suspensions. Physical and chemical changes (excluding separating the components of a mixture).

Chapter 3: Atoms and Molecules

In NCERT Class 9 Science Chapter 3, students will learn the laws of chemical combination, atoms and molecules. They will get to know how to write a chemical formula, molecular mass and mole concepts and some numerical problems related to these concepts.

Topics Covered in Class 9 Science Chapter 3 Atoms and Molecules  :

Particle nature and their basic units: Atoms and molecules, Law of Chemical Combination, Chemical formula of common compounds, Atomic and molecular masses.

Chapter 4: Structure of the Atom

This chapter of NCERT Class 9 Science deals with the various atomic models of atoms that were proposed by different scientists. In addition to it, this chapter also covers electrons’ distribution in different orbits, calculation of valency, atomic number and mass number.

Topics Covered in Class 9 Science Chapter 4 Structure of the Atom  :

Structure of atoms: Electrons, protons and neutrons, Valency, Atomic Number and Mass Number, Isotopes and Isobars.

Chapter 5: The Fundamental Unit of Life

This chapter is related to Biology. In this chapter, students will get to know that the cell is the fundamental unit of life. The whole chapter revolves around the cell and its structural organization, in which students will learn about the plasma membrane, cell wall, nucleus, cytoplasm and structure of an animal cell.

Topics Covered in Class 9 Science Chapter 5 The Fundamental Unit of Life  :

Cell – Basic Unit of life: Cell as a basic unit of life; prokaryotic and eukaryotic cells, multicellular organisms; cell membrane and cell wall, cell organelles and cell inclusions; chloroplast, mitochondria, vacuoles, endoplasmic reticulum, Golgi apparatus; nucleus, chromosomes – basic structure, number.

Also, access the following resources for Class 9 Chapter 5 The Fundamental Unit of Life at BYJU’S:

• The Fundamental Unit of Life Class 9 CBSE Notes – Chapter 5
• Revision Notes For Class 9 Science Chapter 5 The Fundamental Unit of Life
• NCERT Exemplar Class 9 Science Solutions for Chapter 5 – The Fundamental Unit of Life

Chapter 6: Tissues

This chapter pertains to the basic definition of tissue and then elaborates on Plant and Animal tissue with proper diagrams. Students will get to know the different types of plant and animal tissues with a detailed explanation of each.

Topics Covered in Class 9 Science Chapter 6 Tissues  :

Tissues, Organs, Organ System, Organism: Structure and functions of animal and plant tissues (only four types of tissues in animals; Meristematic and Permanent tissues in plants).

Chapter 7: Diversity in Living Organism

This chapter deals with the classification of plants and animals. Students get to know that all living organisms are divided into 5 kingdoms namely Monera, Protista, Fungi, Plantae and Animalia. It also describes the classification and evolution, the hierarchy of classification.

Chapter 8: Motion

NCERT Class 9 Science Chapter 8 describes motion, the speed with direction, rate of change of velocity, and graphical representation of motion. Also, students will find the 3 equations of motion and numerical problems related to them. Overall, this chapter will be a mix of theory as well as the numerical part.

Topics Covered in Class 9 Science Chapter 8 Motion :

Motion: Distance and displacement, velocity; uniform and non-uniform motion along a straight line; acceleration, distance-time and velocity-time graphs for uniform motion and uniformly accelerated motion, elementary idea of uniform circular motion.

Chapter 9: Force and Law of Motion

This chapter explains the 3 laws of motion with the help of diagrams and examples. Below are the 3 laws of motion:

1. First law of motion: An object continues to be in a state of rest or of uniform motion along a straight line unless acted upon by an unbalanced force.
2. Second law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.
3. Third law of motion: To every action, there is an equal and opposite reaction, and they act on two different bodies.

Topics Covered in Class 9 Science Chapter 9 Force and Law of Motion  :

Force and Newton’s laws: Force and Motion, Newton’s Laws of Motion, Action and Reaction forces, Inertia of a body, Inertia and mass, Momentum, Force and Acceleration.

Chapter 10: Gravitation

In chapter 10 of NCERT Class 9 Science, students will learn the universal law of gravitation and its importance, free fall, mass, weight, thrust and pressure, Archimedes’ principle and relative density. Students will also find numerical problems related to these topics.

Topics Covered in Class 9 Science Chapter 10 Gravitation :

Gravitation: Gravitation; Universal Law of Gravitation, Force of Gravitation of the earth (gravity), Acceleration due to Gravity; Mass and Weight; Free fall.

Floatation: Thrust and Pressure. Archimedes’ Principle; Buoyancy.

Chapter 11: Work and Energy

In this chapter, the concept of work is defined with different activities, numerical and examples. The chapter also deals with energy and its different forms. Examples are given to explain all types of energy. The chapter ends with the topic “rate of doing work”.

Topics Covered in Class 9 Science Chapter 11 Work and Energy  :

Work, Energy and Power: Work done by a Force, Energy, power; Kinetic and Potential energy; Law of conservation of energy (excluding commercial unit of Energy).

Chapter 12: Sound

Chapter 12 of CBSE Class 9 Science, deals with concepts such as the production of sound, propagation of sound, the reflection of sound, range of hearing, applications of ultrasound, and the structure of the human ear. A few numericals are also there in the chapter which can only be solved after understanding the concepts. So, students must grasp and study the chapter carefully.

Topics Covered in Class 9 Science Chapter 12 Sound :

Sound: Nature of sound and its propagation in various media, speed of sound, range of hearing in humans; ultrasound; reflection of sound; echo.

Chapter 13: Why Do We Fall Ill?

NCERT Class 9 Science chapter 13 deals with health issues and different types of diseases. It covers topics like; Health and its failure, disease and its cause, infectious diseases. This chapter is added to make students aware of different types of diseases so that they take care of their health and be fit and healthy.

Chapter 14: Natural Resources

We are blessed with natural resources. These are essential to meet the basic requirements of all forms of life on Earth. So, this chapter has been included by NCERT to provide knowledge on the types of resources available on the Earth. This chapter deals with the topics like air, water, soil, the biogeochemical cycle and the ozone layer, its importance and how humans are polluting them.

Chapter 15: Improvement in Food Resources

The last chapter of NCERT Class 9 Science covers topics like Improvement in crop yields, manure, fertilizer, storage of grains, and animal husbandry. This chapter provides knowledge regarding agriculture, farming and dairy.