The flash point is the lowest temperature at which a liquid produces enough vapor to form an ignitable mixture with air. Essentially, it’s the temperature at which the liquid can catch fire when exposed to an open flame or spark.

For example, if you heat a flammable liquid like gasoline, at a certain point, its vapors will ignite when exposed to a spark or flame — that’s its flash point. It’s an important property for determining the flammability and safety of substances in various settings like laboratories, industrial environments, or transportation.

There are two main types of flash points:

1. Closed cup flash point: The test is done in a sealed container, which prevents the vapor from dispersing, making it a more sensitive measure.
2. Open cup flash point: The test is done in an open container, allowing more vapor to escape, so it typically gives a higher flash point than the closed cup method.

Different substances have different flash points. For example:

• Gasoline has a flash point of around -45°F (-43°C).
• Water has a flash point of 212°F (100°C), but it’s non-flammable under normal conditions.