| Classwise Additional Science Questions with Solutions (Class 6th to 10th) | ||||||||||||||
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| Classwise Additional Science Questions with Solutions (Class 11th) | ||||||||||||||
| Physics | Chemistry | Biology | ||||||||||||
| Classwise Additional Science NCERT Questions with Solutions (Class 12th) | ||||||||||||||
| Physics | Chemistry | Biology | ||||||||||||
Class 8th Science Additional Questions
1. Crop Production And Management
This chapter focuses on the agricultural practices necessary for growing crops efficiently, crucial for India's large agrarian population. It covers the sequential steps from preparing the soil (ploughing, levelling) and sowing seeds, to providing essential nutrients through manure and fertilisers, ensuring timely irrigation, protecting crops from weeds and pests, harvesting the mature produce, and finally, storing the grains properly to prevent loss. Understanding these processes is fundamental for maximizing yield and ensuring food security in the country.
2. Microorganisms : Friend And Foe
This chapter explores the world of **microorganisms**, tiny living beings found everywhere, some beneficial and others harmful. It discusses various types of microbes like bacteria, fungi, protozoa, and viruses. Their positive roles include making curd and bread, producing antibiotics, decomposing waste, and increasing soil fertility. The chapter also highlights their negative impact as **disease-causing agents** in humans, plants, and animals (e.g., causing typhoid, malaria). Methods to prevent diseases and preserve food from microbial spoilage are also covered, showcasing their dual nature.
3. Synthetic Fibres And Plastics
This chapter introduces **synthetic fibres** (man-made fibres like nylon, rayon, polyester, acrylic) and **plastics**. It discusses how these materials are synthesized from chemicals and explores their properties, such as strength, durability, lightness, and resistance to corrosion, which make them useful for a wide range of applications in daily life and industry. However, the chapter also addresses the environmental concerns associated with plastics due to their non-biodegradable nature, emphasizing the need for responsible use, recycling, and proper waste management.
4. Materials : Metals And Non-Metals
This chapter classifies materials into **metals** and **non-metals** based on their distinct physical and chemical properties. Physical properties include lustre, hardness, malleability (beaten into sheets), ductility (drawn into wires), conductivity of heat and electricity, and state at room temperature. Chemical properties cover their reactions with oxygen, water, acids, and bases. The **Reactivity Series** of metals is introduced to understand how metals displace each other. The chapter highlights the diverse uses of metals and non-metals in technology, construction, and everyday items based on their properties.
5. Coal And Petroleum
**Coal** and **petroleum** are essential **fossil fuels**, formed over millions of years from the decomposition of ancient organisms. This chapter explains their formation process, extraction (mining, drilling), and the various useful products obtained from their processing (e.g., coke, coal tar, gasoline, diesel, kerosene, LPG). These non-renewable resources are major sources of energy globally and in India. The chapter emphasizes the importance of their judicious use and the urgent need to explore and develop alternative energy sources for the future due to their finite nature and environmental impact.
6. Combustion And Flame
This chapter focuses on **combustion**, the chemical process of burning, which involves a substance reacting rapidly with oxygen to produce heat and light. It identifies **combustible substances** and the conditions necessary for combustion (presence of fuel, oxygen, and reaching the ignition temperature). Different types of combustion (rapid, spontaneous, explosion) are discussed. The structure of a **flame**, seen when gaseous substances undergo combustion, is explained with its different zones. The chapter also covers **fire control** methods by removing one or more of the essential conditions for combustion, highlighting practical safety knowledge.
7. Conservation Of Plants And Animals
This chapter stresses the vital importance of preserving **biodiversity** and natural habitats. It discusses the causes and consequences of **deforestation**, such as soil erosion, desertification, and impact on climate and wildlife. Concepts like **endangered species**, extinct species, flora, fauna, endemic species, and migratory birds are introduced. Different methods of **conservation**, including establishing **national parks**, **wildlife sanctuaries**, and **biosphere reserves** in India, are discussed as strategies to protect forests and wildlife and maintain ecological balance for future generations.
8. Cell — Structure And Functions
This chapter introduces the **cell** as the basic structural and functional unit of all living organisms. It recounts the discovery of the cell and discusses the diversity in cell number (unicellular, multicellular), shape, and size. The fundamental components of a cell, including the **cell membrane**, **cell wall** (in plant cells), **cytoplasm**, and **nucleus**, are described. Various **cell organelles** located within the cytoplasm, such as vacuoles, plastids (chloroplasts), and mitochondria, are introduced with their basic functions, providing a microscopic view of life and the differences between plant and animal cells.
9. Reproduction In Animals
This chapter explains how animals produce new individuals, ensuring the continuity of their species. It covers both **asexual reproduction**, which involves a single parent (e.g., binary fission in Amoeba, budding in Hydra), and **sexual reproduction**, which involves the fusion of male and female gametes (**fertilisation**). The chapter details both internal (inside the body) and external (outside the body) fertilisation. The development of the embryo and different life cycles in animals, including **metamorphosis** in organisms like frogs and silkworms, are also discussed, illustrating the varied reproductive strategies in the animal kingdom.
10. Reaching The Age Of Adolescence
**Adolescence** is the transitional period between childhood and adulthood, marked by the onset of **puberty** and rapid physical, emotional, and psychological changes. This chapter discusses the changes associated with puberty, including growth spurts, changes in body shape and voice, increased activity of sweat and sebaceous glands, and the development of secondary sexual characteristics, driven by hormones. The chapter also highlights the importance of personal hygiene, proper nutrition, and understanding reproductive health during this crucial stage of development, providing essential information for teenagers navigating these changes.
11. Force And Pressure
This chapter introduces the concepts of **force** and **pressure**. A force is defined as a push or pull that can change an object's state of motion (at rest or in motion) or change its shape. Different types of forces, both contact (e.g., muscular, friction) and non-contact (e.g., magnetic, electrostatic, gravitational), are discussed. **Pressure** is defined as the force acting per unit area ($\textsf{Pressure} = \frac{\textsf{Force}}{\textsf{Area}}$), explaining that it depends on both the magnitude of the force and the area over which it is applied. Pressure exerted by liquids and gases is also covered, illustrating its presence and effects in everyday situations.
12. Friction
**Friction** is a force that opposes the relative motion between two surfaces in contact. This chapter explains the cause of friction (interlocking of surface irregularities) and discusses different types: static friction (opposing motion initiation), sliding friction (opposing sliding), and rolling friction (opposing rolling), noting that rolling friction is generally less than sliding friction. The chapter explores situations where friction is beneficial (e.g., walking, braking) and where it is undesirable (e.g., wear and tear), and discusses methods to increase or decrease friction, such as using lubricants or changing the surface.
13. Sound
**Sound** is a form of energy that is produced by **vibrations**. This chapter explains how sound is produced and requires a material medium (solid, liquid, or gas) to travel, demonstrating that it cannot propagate through a vacuum. Key characteristics of sound waves, such as amplitude (related to loudness), frequency (related to pitch), time period, and speed, are discussed. The chapter differentiates between musical sound and noise, highlights the harmful effects of **noise pollution**, and suggests measures to control it, emphasizing the physical nature of sound and its impact.
14. Chemical Effects Of Electric Current
This chapter explores the **chemical changes** that can occur when electric current passes through certain liquids known as electrolytes. It introduces the process of **electrolysis**, where electricity is used to decompose a substance. Experiments demonstrating the conduction of electricity through various liquids and the resulting chemical effects (e.g., deposition of metal) are discussed. The chapter highlights practical applications of these effects, such as **electroplating**, a process used to coat a metal object with a thin layer of another metal for protection or decoration, common in jewellery, automotive parts, and utensils.
15. Some Natural Phenomena
This chapter focuses on understanding two powerful and sometimes destructive **natural phenomena**: **lightning** and **earthquakes**. It explains how **lightning** is caused by the accumulation and discharge of electric charges in storm clouds and between clouds and the ground, discussing necessary safety measures during thunderstorms. **Earthquakes** are described as sudden vibrations in the Earth's crust caused by the movement of tectonic plates. The chapter covers their causes and effects and discusses safety precautions to take during an earthquake, raising awareness about these natural hazards.
16. Light
This chapter delves into the properties of **light** and how we perceive the world visually. It reinforces that light travels in straight lines. The phenomenon of **reflection**, the bouncing back of light from surfaces like mirrors, is explained, including the laws of reflection and image formation by **plane mirrors**. The chapter also introduces image formation by **spherical mirrors** (concave and convex) using ray diagrams. The structure and working of the **human eye**, common eye defects and their correction, and the importance of eye donation are also covered, highlighting the role of light and vision.
17. Stars And The Solar System
This chapter takes you on an astronomical journey, exploring celestial objects beyond Earth. It introduces **stars**, their vast distances, and **constellations** (patterns of stars). The **Solar System**, consisting of the Sun, eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune), asteroids, comets, and meteoroids, is described. The Moon, its phases, and artificial satellites are also covered. The chapter provides a basic understanding of our place in the universe and the movements of celestial bodies, sparking curiosity about astronomy and space.
18. Pollution Of Air And Water
This chapter addresses the critical environmental issue of **pollution**, focusing on **air** and **water** pollution. It identifies the major sources and types of **air pollutants** (e.g., smoke, dust, harmful gases from vehicles and industries) and their adverse effects on human health, plants, and the environment (e.g., acid rain). Similarly, it discusses the sources and types of **water pollutants** (e.g., sewage, industrial waste, agricultural chemicals) and their consequences for aquatic life and human health. The chapter stresses the need for measures to prevent and control air and water pollution for a healthier environment, a significant challenge in India.