NCERT Solutions for Class 9 Science

Chapter 1: MATTER IN OUR SURROUNDINGS

In this chapter the main key concepts you will be reading are 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?

In this chapter the main key concepts you will be reading are Elements, compounds and mixtures. Heterogeneous and homogenous mixtures, colloids and suspensions.

Chapter 3: ATOMS AND MOLECULES

In this chapter the main key concepts you will be reading are Atoms and molecules, Law of constant proportions, Atomic and molecular masses. Mole concept: Relationship of mole to mass of the particles and numbers.

Chapter 4: STRUCTURE OF THE ATOM

In this chapter the main key concepts you will be reading are Electrons, protons and neutrons, valency, chemical formula of common compounds. Isotopes and Isobars.

Chapter 5: THE FUNDAMENTAL UNIT OF LIFE

In this chapter the main key concepts you will be reading are 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.

Chapter 6: TISSUES

In this chapter the main key concepts you will be reading are 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 ORGANISMS

In this chapter the main key concepts you will be reading are Diversity of plants and animals-basic issues in scientific naming, basis of classification. Hierarchy of categories/groups, Major groups of plants (salient features) (Bacteria, Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms).

Chapter 8: MOTION

In this chapter the main key concepts you will be reading are 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, derivation of equations of motion by graphical method; elementary idea of uniform circular motion.

Chapter 9: FORCE AND LAWS OF MOTION

In this chapter the main key concepts you will be reading are Force and Motion, Newton’s Laws of Motion, Action and Reaction forces, Inertia of a body, Inertia and mass, Momentum, Force and Acceleration. Elementary idea of conservation of Momentum.

Chapter 10: GRAVITATION

In this chapter the main key concepts you will be reading are Gravitation; Universal Law of Gravitation, Force of Gravitation of the earth (gravity), Acceleration due to Gravity; Mass and Weight; Free fall.

Chapter 11: WORK AND ENERGY

In this chapter the main key concepts you will be reading are Work done by a Force, Energy, power; Kinetic and Potential energy; Law of conservation of energy.

Chapter 12: SOUND

In this chapter the main key concepts you will be reading are Nature of sound and its propagation in various media, speed of sound, range of hearing in humans; ultrasound; the reflection of sound; echo and SONAR. Structure of the Human Ear (Auditory aspect only).

Chapter 13: WHY DO WE FALL ILL?

In this chapter the main key concepts you will be reading are Bio-geo chemical cycles in nature: Water, Oxygen, Carbon and Nitrogen.

Chapter 14: NATURAL RESOURCES

In this chapter the main key concepts you will be reading are Air, Water, and Soil. Air for respiration, for combustion, for moderating temperatures; movements of air and its role in bringing rains across India. Air, water and soil pollution (brief introduction). Holes in ozone layer and the probable damages.

Chapter 15: IMPROVEMENT IN FOOD RESOURCES

In this chapter the main key concepts you will be reading are Plant and animal breeding and selection for quality improvement and management; Use of fertilizers and manures; Protection from pests and diseases; Organic farming.