Certified Fire Investigator Practice Exam

What typically causes an explosion?

1. A decrease in temperature

2. External physical impact

3. The release of gases under pressure

4. A slow chemical process

The correct answer is: The release of gases under pressure

An explosion is typically caused by the rapid release of gases under pressure. This phenomenon occurs when a substance undergoes a sudden change, such as a chemical reaction or a physical change, that generates a large volume of gas in a very short time. The buildup of pressure may exceed the structural limits of a container or the surrounding environment, leading to an explosive event. In contrast, a decrease in temperature generally leads to a reduction in pressure and is unlikely to trigger an explosion. External physical impact might cause damage or ignition but does not intrinsically create the conditions necessary for an explosion. A slow chemical process does not result in the rapid release of gas; instead, it leads to more gradual changes that do not produce explosive characteristics. Thus, the correct cause of an explosion is the rapid release of gases under pressure.