• By noor arora
• 23 Oct 2022

Introduction → Incident Ray: The ray of light which is directed towards the mirror is called incident ray. → Reflected Ray: The ray of light which bounces back after reflection is called reflected ray. → Normal: It is perpendicular to the reflecting surface at the point

• By noor arora
• 23 Oct 2022

Chapter 15 Some Natural Phenomena notes class 8th science A Natural Phenomenon is anything that occurs on its own in nature without any kind of human intervention. For example, the weather of a place, fog, storms, winds, tides, volcanic eruptions and

• By noor arora
• 23 Oct 2022

Conductors and insulators Figure 1 Conductors and Insulators of Electricity A conductor is any material or substance that allows electricity to flow through it. An insulator is any substance or material that prevents the flow of electricity through it. Any

• By noor arora
• 23 Oct 2022

Introduction → Sound helps us to communicate with one another and plays an important role in our life. → Vibrating body produces sound. → In this chapter, we will know about how sound is produced and how we hear them.

• By noor arora
• 23 Oct 2022

Introduction → The vehicles, any object, moving over the surface of another object slows down due to the force of friction applied on it. Friction → It is an opposing force that acts between surfaces in contact moving with respect

• By noor arora
• 23 Oct 2022

Introduction → Actions like picking, opening, shutting, kicking, hitting, lifting, flicking, pushing, pulling are often used to describe certain tasks. → Each of these actions usually results in some kind of change in the motion of an object. Force →

• By noor arora
• 23 Oct 2022

Adolescence → The time period when the body undergoes changes to reach reproductive maturity is known asadolescence. → It begins around the age of 11 and lasts till about 18 or 19 years of age. → Adolescence in girls can

• By noor arora
• 23 Oct 2022

Male Reproductive System → It consists of testis, sperm duct and penis. → Testes are involved in the production of male gametes called sperms. → Millions of sperms are produced by the testes. → Each sperm consists of three parts:

• By noor arora
• 23 Oct 2022

Cell Discovery of the Cell→ Cells are the basic structural units and the building blocks of all living organisms.→ Cell was discovered by Robert Hooke in 1665 after observing a piece of cork under a magnifying device. → Robert Hooke

• By noor arora
• 23 Oct 2022

Deforestation → Deforestation is the process of clearing of forests in order to use the land for industrial, agricultural, and other purposes. Causes of Deforestation → Natural causes→ Forest fire→ Severe droughts→ Man-made causes→ Using land for agricultural purposes→ Rapid