Combustible Substances:

Combustible substances are materials that can undergo combustion (burning) when exposed to heat, oxygen, and an ignition source. They have the ability to sustain a chemical reaction called combustion, which release energy in the form of heat and light. Combustible substances are commonly used as fuels for various purposes, such as heating, cooking, and generating electricity.

Characteristics of Combustible Substances:
- Flammability: Combustible substances have the ability to catch fire and burn.
- Ignition Temperature: They have a specific temperature at which they start to burn.
- Fuel and Oxygen: Combustible substances require a fuel source (the substance itself) and oxygen to sustain combustion.
- Energy Release: During combustion, combustible substances release energy in the form of heat and light.
- Examples: Common examples of combustible substances include wood, paper, gasoline, diesel, natural gas, and oil.

Non-Combustible Substances:

Non-combustible substances, on the other hand, are materials that do not easily catch fire or burn. These substances have a high resistance to combustion and are not easily affected by heat and flames. Non-combustible materials are commonly used in construction and manufacturing industries to ensure fire safety and prevent the spread of fires.

Characteristics of Non-Combustible Substances:
- Fire Resistance: Non-combustible substances do not support combustion and do not contribute to the spread of fires.
- High Melting Point: They have a high melting point, which makes them resistant to heat and flames.
- Examples: Examples of non-combustible substances include metals like steel, concrete, bricks, glass, stone, and certain types of plastics.

Differences between Combustible and Non-Combustible Substances:
- Combustibility: Combustible substances have the ability to burn, while non-combustible substances do not easily catch fire or burn.
- Flammability: Combustible substances are highly flammable and can ignite easily, while non-combustible substances have a high resistance to ignition and combustion.
- Fire Safety: Non-combustible substances are commonly used in construction to enhance fire safety, while combustible substances need to be handled and stored with caution to prevent accidents and fires.
- Usage: Combustible substances are commonly used as fuels, while non-combustible substances are used in various applications where fire resistance is required.
- Melting Point: Non-combustible substances generally have a higher melting point compared to combustible substances, which helps them resist heat and flames.

combustible substance are the substance which burn and help for burning and non combustible substance does not burn and does not help for burning.