# CLASS – 8 (PHYSICS, CHEMISTRY, BIOLOGY & MATHEMATICS)

Doubtbox is the latest innovative product from the founders of eTutor, which is used by half a million students across the globe. This Interactive Digital Content Repository has 8000 animated topics and one lakh questions with answers for Classes 1-12 .

Doubtbox pen drive, an excellent tuition master at home, facilitating self learning by students, available for Classes 1-12, based on CBSE syllabus, with effective blending of ICSE and State Boards syllabus. Once they are set up in the home computer/lap top, students can study any lesson according to their convenience and do home work easily, watching the lessons enriched with multimedia. All the topics are explained with quality animations, graphics, pictures and diagrams along with audio explanations. Students will enjoy lessons as if seeing an animated, topic-based film.

**System Requirements:**

- Processor – Minimum:1 GHZ, RAM – Minimum:2 GB
- Disk Space – Minimum 10 GB Free space
- Screen resolution – 1280 x 720 or above
- Operating System – Windows 7 or above

**Doubtbox Features:**

- Latest syllabus
- Animated video lessons
- Exciting visuals
- Audio explanations
- Multiple choice questions
- Assessments
- Time bound test
- Model test papers
- Previous years question papers
- NCERT solutions

## PRODUCT DESCRIPTION

**Topics Covered in Doubtbox Educational Pen Drive**

Chapter 1. Crop Production and Management

Agricultural Practices, Basic Practices of Crop Production, Preparation of Soil , Sowing, Adding Manure and Fertilisers, Irrigation, Protection from Weeds, Harvesting, Storage, Food from Animals

Chapter 2. Micro organisms : Friend and Foe

Microorganisms , Where do Microorganisms Live?, Microorganisms and Us, Harmful Microorganisms, Food Preservation, Nitrogen Fixation, Nitrogen cycle

Chapter 3. Conservation of Plants and Animals

Deforestation and Its Causes, Consequences of Deforestation, Conservation of Forest and Wildlife, Biosphere Reserve, Flora and Fauna, Endemic Species, Wildlife Sanctuary, National park, Red Data Book, Migration, Reforestation and Recycling of Paper

Chapter 4. Cell – Structure and Functions

Discovery of the Cell, The Cell Organisms show Variety in Cell Number, Shape and Size, Cell Structure and Function, Parts of the Cell, Comparison of Plant and Animal Cells

Chapter 5. Reproduction in Animals

Modes of Reproduction Sexual Reproduction, Asexual Reproduction

Chapter 6. Reaching the age of Adoloscence

Adolescence and Puberty, Changes at Puberty, Secondary Sexual Characters, Role of Hormones in Initiating Reproductive Function, Reproductive Phase of Life in Humans, How is the Sex of the Baby determined?, Hormones other than Sex Hormones, Role of Hormones in completing the Life History of Insects and Frogs, Reproductive Health

Chapter 1.Synthetic Fibres and Plastics

Synthetic fibres, Types of synthetic fibres, Characteristics of Synthetic Fibres, Plastics, Plastics as Materials of Choice, Plastics and the Environment

Chapter 2. Materials: Metals and Non –metals

Physical Properties of Metals and Non-metals, Chemical Properties of Metals and Non-metals,

Uses of Metals and Nonmetals

Chapter 3. Coal and Petroleum

Coal, Petroleum and refining of petroleum, Natural Gas, Some Natural Resources are Limited

Chapter 4. Combustion and Flame

What is Combustion?, How do We Control Fire?, Types of Combustion, Flame, Structure of a Flame, What is a Fuel?, Fuel Efficiency

Chapter 5. Pollution of Air and Water

Air Pollution, How does Air Get Polluted?, Case study :The Taj Mahal, Greenhouse Effect, What can be Done?, Water Pollution, How does Water Get Polluted?, What is Potable Water and How is Water Purified ?

Chapter 1. Force and Pressure

Force – A Push or a Pull, Forces are due to an Interaction, Exploring Forces, A Force can change the state of motion, Force can Change the Shape of an Object, Contact Forces, Non-contact Forces, Pressure, Pressure exerted by Liquids and Gases, Atmospheric Pressure

Chapter 2. Friction

Force of Friction, Factors affecting Friction, Friction : A Necessary Evil, Increasing and Reducing Friction, Wheels Reduce Friction, Fluid Friction

Chapter 3. Sound

Sound is Produced by a Vibrating Body, Sound Produced by Humans, Sound Needs a Medium for Propagation, We hear Sound through Our Ears, Amplitude, Time Period And Frequency of a Vibration, Audible and Inaudible Sounds, Noise and Music, Noise Pollution

Chapter 4. Chemical Effects of Electric Current

Do Liquids Conduct Electricity?, Chemical Effects of Electric Current, Electroplating

Chapter 5. Some Natural Phenomena

Lightning, Charging by rubbing, Types of Charges and their Interaction, Lightning Safety, Earthquakes

Chapter 6. Light

What makes Things Visible, Laws of Reflection, Regular and Diffused Reflection, Multiple Images, Sunlight — White or Coloured, What is inside Our Eyes?, Care of Eyes, What is a Braille System?

Chapter 7. Stars and the Solar System

The Moon, The Stars, Constellations, The Solar System, Some Other Members of the Solar System

Chapter 1. Rational Numbers

Introduction, Properties of Rational Numbers, Representation of Rational Numbers on the Number Line, Rational Numbers between Two Rational Numbers

Chapter 2. Linear Equations in One variable

Introduction, Solving Equations which have Linear Expressions on one Side and Numbers on the other Side, Some Applications, Solving Equations having the Variable on both Sides, Some More Applications, Reducing Equations to Simpler Form

Chapter 3. Understanding Quadrilaterals

Introduction, Polygons, Kinds of Quadrilaterals, Trapezium

Chapter 4. Practical Geometry

Introduction, Constructing a Quadrilateral, Some Special Cases

Chapter 5. Data Handling

Looking for Information, Organising Data, Grouping Data, Circle Graph or Pie Chart, Chance and Probability

Chapter 6. Squares and Square Roots

Introduction, Square Roots-Finding square roots, Finding square root through repeated subtraction, Finding square root through prime factorisation, Finding square root by division method

Chapter 7. Cubes and Cube Roots

Introduction, Cubes – Smallest multiple that is a perfect cube, Cube Roots – Cube root through prime factorisation method

Chapter 8. Comparing Quantities

Recalling Ratios and Percentages, Finding the Increase or Decrease Percent, Finding Discounts,Prices Related to Buying and Selling (Profit and Loss), Sales Tax/Value Added Tax, Compound Interest, Rate Compounded Annually or Half Yearly(Semi Annually)

Chapter 9. Algebraic Expressions and Identities

What are Expressions?, Terms, Factors and Coefficients, Monomials, Binomials and Polynomials, Like and Unlike Terms, Addition and Substraction of Algebraic Expressions, Multiplying a Monomial by a Polynomial, Multiplying a Polynomial by a Polynomial

Chapter 10. Visualising Solid Shapes

Introduction, Views of 3D-Shapes, Mapping Space Around Us, Faces, Edges and Vertices

Chapter 11. Mensuration

Introduction, Let us Recall, Area of Trapezium, Area of a General Quadrilateral, Solid Shapes, Surface Area of Cube, Cuboid and Cylinder, Volume of Cube, Cuboid and Cylinder, Volume and Capacity

Chapter 12. Exponents and Powers

Introduction, Powers with Negative Exponents, Laws of Exponents, Use of Exponents to Express Small Numbers in Standard Form

Chapter 13. Direct and Inverse Proportions

Introduction, Direct Proportion, Inverse Proportion

Chapter 14. Factorisation

Introduction, What is Factorisation?, What is Factorisation?, Division of Algebraic Expressions,

Division of Algebraic Expressions continued(Polynomial ÷ Polynomial)

Chapter 15. Introduction to Graphs

Introduction, Linear Graphs, Some Applications

Chapter 16. Playing with Numbers

Introduction, Numbers in General Form, Games with Numbers, Letters for Digits, Tests of Divisibility

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