Coal and Petroleum | Full Chapter Revision under 30 mins | Class 8 Science

The instructor Kriti introduces the session, focused on revising the entire chapter on coal and petroleum within 30 minutes. She begins with the basics, explaining what fuels are – substances providing energy – and spans various states like solid, liquid, and gas. Examples include wood, petrol, and hydrogen, emphasizing that not all fuels are necessarily solid or liquid. The session underscores the essential role of energy in our daily lives.

Kriti continues to explain fossil fuels, formed from dead plants and animals over millions of years. She highlights the essential roles of temperature, pressure, and time in forming fossil fuels such as coal, petroleum, and natural gas. The focus is on understanding their formation process for the session, which primarily revolves around these three fossil fuels.

The formation process of coal is elaborated; it began around 300 million years ago when forests were buried under soil, forming coal under high pressure and temperature, rich in carbon. Characteristics of coal are discussed, including its hardness, black color, and carbon content, and products obtained from its destructive distillation – coke, coal gas, and coal tar – are explored along with their uses.

Petroleum, derived from marine organisms, is also discussed. It is called 'black gold' due to its value and widespread uses, extracted through a process that separates its fractions based on boiling points. Various petroleum products and their applications, like LPG, petrol, and kerosene, are outlined, indicating the broad applications and importance justifying its 'black gold' designation.