Chapter 2. Is Matter Around Us Pure

Class 9 Science Chapter 2 explains about all types of substances, whether it is pure or a mixture of two or more pure substances. Homogeneous and heterogeneous mixture and their properties are frequently asked in school exams of class 9 Science. We have to learn here about how many types of solutions are there, how to prepare these solutions and how to find the concentration of a given solution. After doing this, we will be able to understand about Suspension and Colloidal also. Properties of Suspension and Colloidal are also crucial as exams point of view. Separating the components from the mixture using various methods are given at the end of this chapter. We can apply these ways in day to day life to understand in a better way.

Chapter 3. Atoms and Molecules

Class 9 Science Chapter 3 deals with Law of Chemical Combination, Law of Conservation of Mass and Law of Constant Proportion. Here, we will study that Atoms and Molecules are the fundamental building blocks of all matter. What is an atom? How big are they? What are the ancient or modern symbols of atoms? These type of questions are new for standard nine students. Atomic Mass and their symbols usually start from grade 9 and play an important role in higher classes. We should understand carefully about important Molecules and their valency along with the knowledge of ions – cation or anion. Using Criss-cross method, writing the formula of any compound is the most important part of Chemistry Chapter 3 of Class 9 Science. Questions based on Molecular mass and Mole concepts are also crucial for the class test or school terminal exams.

Chapter 4. Structure of the Atom

Class 9 Science Chapter 4 is based on sub-atomic particle like a proton – p, neutron – n and electron – e. It also explains the various steps of the discovery of the structure of atoms and its subparts. Structure of Atom includes the atomic models of J. J. Thomson, Rutherford and Bohr. Rutherford’s experiment, its observation and conclusion are considered as important topics of Chemistry Chapter 4 of Class 9 Science. We have to learn here about Valency, Atomic Number, Mass Number and their correlation with each other. We should understand the difference between Isotopes and Isobars to remove any confusion in further classes.

Chapter 5. The Fundamental Unit of Life

Class 9 Science Chapter 5 is the first chapter of Biology in standard 9. This chapter tells us how Robert Hooke discovered the cell using a slice of cork. Cells are too small to see through naked eyes, but we can see the cell by microscope making temporary mounts of peels of onions. Here, we will be able to know about cells in the human body like Bone cells, Blood cells, Smooth muscles cells, Nerve cells, etc. The structural organisation of a cell, Plasma membrane and its phenomena with Isotonic, Hypotonic and Hypertonic solutions are briefly described in grade 9 Science, Chapter 5 Biology section. We should know about the function of Cell wall, Nucleus and Cytoplasm in a cell. A complete description of Plant cell and Animal cell with their components like Golgi Apparatus, Lysosomes, Mitochondria, Plastid, Vacuoles and Cell division is the main point of this chapter to study.

Chapter 6. Tissues

Class 9 Science Chapter 6 describes about the plant and animal tissues. Plant tissues include the explanation about Meristematic tissue – for the growth of plants and Permanent tissue – permanent in shape, size and function (simple and complex permanent tissues). Animal tissues cover the topics related to Epithelial tissue (also known as covering or protective tissue), Connective tissue, Muscular tissue and Nervous tissue. Nerve cells or Neurons are the fundamental units of the nervous system. Nervous tissues are made up of these Neurons. Neurons are the longest cells in the human body. An individual nerve cell may be up to a metre long.

Chapter 7. Diversity in Living Organisms

Class 9 Science Chapter 7 explains about the classification of the living being in a systematic order. We will study here that the classification of life forms will be closely related to their evolution. Biologists, Ernst Haeckel, Robert Whittaker and Carl Woese, have tried to classify all living organisms into called kingdoms. The classification Whittaker divided all the living being into five kingdoms as Monera, Protista, Fungi, Plantae and Animalia. Further classification is done by naming the sub-groups Phylum or Division, Class, Order, Family, Genus and Species. In Class 9 Science Chapter 7, we have to compare the living being within the same kingdom or some time with the other kingdom also. In the end, we will study the Nomenclature – systematic naming of living organisms.

Chapter 8. Motion

Class 9 Science Chapter 8 includes all the terms which describe the motion of an object. Most of the topics are based on the motion on a straight line or uniform motion. During the study of uniform or non-uniform motion, we will learn to find the average speed or speed during a specific duration. Chapter 8 of Class 9 Science contains many numerical problems in Physics following the three equation of motion. We should understand about the difference between velocity and speed as well as distance and displacement. Graphical representation of motion and the derivation of three equations of motion with a graphical method are frequently asked in school examination. Concepts of uniform circular motion and numerically based on it are also important for exams.

Chapter 9. Force and Laws of Motion

Class 9 Science Chapter 9 starts with focusing on the balanced and unbalanced force. Later on, it includes the impact of Friction force and Inertia also. The main motive to study Chapter 9 of Class 9 Science is to understand the laws of motion under the influence of force. Here, we will start from First law of motions and Inertia of body. Later on Second law of motion along with the law of conservation of momentum. We have to do all the intext questions and exercises questions based on particular on laws of motions and momentum. In the end, there are many reasoning questions based on the Third law of motion are given to understand about the law of Action-Reaction.

Chapter 10. Gravitation

Class 9 Science Chapter 10 is based on the concepts of Gravitation, Universal Law of Gravitation and Gravity. We should know that every object is attracted by other objects with a variable gravitational pull according to what the Gravitational Law states. The relation between Universal Gravitational Constant G and Gravitational Acceleration g is also important for terminal exams or class test. Chapter 10 of Class 9 Science also states about the difference between Mass and Weight considering the values of g. We know that G is constant, but the value of gravity varies according to the varying radius of Earth. Value of g is maximum at poles and least at the equator due to the elliptical structure of Earth. Concepts of Buoyancy, Buoyant force, Pressure and Thrust, Archimedes’ principle of floatation and Relative Density are the topic for exam preparation.

Chapter 11. Work and Energy

Class 9 Science Chapter 11 explains that Work and Energy are the same things only the states are changed. Work is concerted to different from of Energy or from Energy we can do work. Questions based on constant force and uniform motions are given as intext questions. Mechanical Energy is basically divided into two kinds as Kinetic Energy and Potential Energy. Kinetic Energy of an object is due to its motion whereas Potential Energy is due to its current position. The sum of Potential and Kinetic Energy is considered as Mechanical Energy. The other forms of energies are Heat Energy, Chemical Energy, Electrical Energy and Light Energy. The Law of Conservation of Energy, Work done, Power and Commercial unit of Energy are the main topics for numerical practice. The relation between 1 Unit and Joules are important for derivation as well as for numerical problems.

Chapter 12. Sound

Class 9 Science Chapter 12 deals with the production and motion of sound. We know that sound travels with different speed in different materials but does not travel in the vacuum as it needs a material medium to travel. Characteristic of a sound wave or Longitudinal wave and concepts of Compression and Rarefaction with Frequency, Amplitude and Speed is important for this segment of class 9 Science. We should also know about the Intensity, Softness, Loudness, Low and High Pitch of sound waves. Most of the numerical in Chapter 12 of Class 9 Science is based on speed, wavelength and frequency. Reflection of sound, including the concept of Echo, are important for conceptual questions. At the end of chapter 12 of 9th Physics, the concepts of Reverberation, instruments based on multiple reflections of sound, range of hearing, Sonar and application of Ultra-Sound waves are given for practice.

Chapter 13. Why do We Fall ill?

Class 9 Science Chapter 13 is focused on Health and related terminology of Health. We will study what Health is, what are the criteria for a healthy person or a disease-free person, and more similar queries. We will also try to know what are the main causes of disease and what is the difference between Acute and Chronic disease. Many diseases may be Infectious or Non-infectious. Mean of spreading, precaution from being ill, the principle of treatment and cure of disease are the concepts given to understand.

Chapter 14. Natural Resources

Class 9 Science Chapter 14 is mainly focused on the Natural Resources available on Earth. Topics for study are the role of the atmosphere in climate control, the appearance of areas of low and high pressure, the direction in which air would flow at night or in the day, causes of rain and means of pollution. We have to study about the availability of water resources and the method of prevention from being polluted. In the end, we will read about biochemical cycles like the water cycle, nitrogen cycle, carbon cycle, oxygen cycle and the greenhouse effect.

Chapter 15. Improvement in Food Resources

Class 9 Science Chapter 15 is based on various methods of improvement of food resources. Improvement of various crops like wheat, rice, maize, millets, etc. yield and improvement of crop variety are an exciting topic to read. Crop production management includes nutrient management like Compost and vermi-compost, Green manure, etc. manure and fertilisers. Irrigation, cropping pattern, crop production management, storage facility, animal husbandry, cattle farming, poultry farming, egg and broiler and fish production are the main points of focus.

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