CBSE English Medium Class 9

Case Study 1: Crop Variety Improvement To feed the growing population, scientists developed high-yielding varieties of wheat that were disease-resistant and required less water. Farmers adopted these seeds to increase production and reduce crop loss. Questions: Case Study 2: Crop Production Practices Farmers in a village compared traditional and modern farming methods. Traditional methods involved

Case Study 1: Production of Sound Reena struck a tuning fork on a rubber pad and brought it near her ear. She noticed vibrations in its prongs, and a humming sound was produced. Sound is produced by vibrating bodies and requires a medium for propagation. Questions: Case Study 2: Longitudinal Waves A slinky experiment was

Case Study 1: Definition of Work Ravi applied a force of 20 N on a box and pushed it 5 m along the floor in the direction of the force. Work done is the product of force and displacement in the direction of the force. Questions: Case Study 2: Work Done Against Friction Aman pushes

Case Study 1: Universal Law of Gravitation Isaac Newton observed an apple falling from a tree and proposed that every object in the universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Questions: Case Study

Case Study 1: Balanced vs. Unbalanced Forces Rahul placed a book on a table. The weight of the book acts downward, and the table exerts an equal upward force. Hence, the book remains at rest. Later, he pushed the book with his hand, and it started moving. Questions: Case Study 2: Inertia (Newton’s First Law)

Case Study 1: Distance vs. Displacement Amit walks 3 km east and then 4 km north. His total distance is 7 km, but his displacement is the straight-line distance from the starting point to the final point. Questions: Case Study 2: Average Speed and Average Velocity Ravi goes from home to school (10 km) in

Case Study 1: Plant Tissue – Meristematic Tissue During a biology practical, Ankit observed the root tip of an onion. He noticed that cells were continuously dividing in this region, making the root grow longer. His teacher explained that these cells are meristematic tissues, found in growing regions of plants like root tips, shoot tips,

Case Study 1: Discovery of Cell In 1665, Robert Hooke observed thin slices of cork under his self-made microscope. He noticed tiny box-like structures that resembled a honeycomb. He called them “cells.” Later, scientists like Schleiden and Schwann proposed the cell theory, which stated that all living organisms are made up of cells and that

Case Study 1: Discovery of Electrons In 1897, J.J. Thomson performed experiments with cathode ray tubes. He found that when high voltage was applied across electrodes in a discharge tube, rays travelled from the cathode to the anode. These rays were deflected by electric and magnetic fields, showing that they carried negative charge. Thus, he

Case Study 1: Law of Conservation of Mass In a laboratory experiment, Sneha heated 5 g of calcium carbonate in a test tube. On heating, it decomposed to give 2.8 g of calcium oxide and 2.2 g of carbon dioxide gas. Her teacher asked her to verify whether the law of conservation of mass is

Case Study 1: Salt Solution Riya dissolved 20 g of salt in 100 mL of water and stirred well. The salt completely disappeared, forming a clear liquid. Questions: Case Study 2: Chalk in Water Sahil mixed chalk powder with water. The mixture looked cloudy and the particles settled down after some time. Questions: Case Study

Case Study 1: Ice in a Glass Ravi left some ice cubes in a glass on the table during summer. After 10 minutes, the ice completely melted into water. His sister noticed droplets forming on the outside of the glass. Questions: Case Study 2: Diffusion of Perfume Ananya sprayed perfume in one corner of her