Video Lecture 1: Fire Dynamics — The Oxygen Dependency and Ignition Temperature

# Video Lecture 1: Fire Dynamics — The Oxygen Dependency and Ignition Temperature
**Instructor:** Dr. Ananya Sharma | **Duration:** ~05:50 mins

### Introduction: The Phenomenon of Fire
Fire has shaped human history. When we strike a match, cook on a gas stove, or witness the fiery ascent of a space rocket, what is fundamentally occurring? It is **Combustion**!

### What is Combustion?
Combustion is a chemical process in which a substance reacts rapidly with oxygen ($\text{O}_2$) to produce heat and light energy. The substance that undergoes combustion is termed a **Combustible substance** or a **Fuel**.

### The Fire Triangle — 3 Mandatory Prerequisites:
1. **Fuel:** The combustible material (solid wood, liquid petrol, or gaseous methane).
2. **Oxygen (Air):** The essential supporter of combustion. Invert an open glass tumbler over a burning candle; within seconds, as the enclosed oxygen is consumed, the flame flickers and dies!
3. **Heat:** Sufficient thermal energy to heat the fuel to its unique threshold.

### Ignition Temperature:
The lowest temperature at which a combustible substance catches fire and sustains burning is called its **Ignition Temperature**.
- A substance will **never** catch fire so long as its temperature remains below its specific ignition temperature! This is why a matchstick resting on a table does not ignite by itself; it must be struck against the rough friction surface to generate frictional heat that raises its tip to its ignition temperature.
- Substances that possess very low ignition temperatures and can easily catch fire with a spark are designated **Inflammable Substances** (e.g., Petrol, Alcohol, LPG).