Eli5: What’s the difference between explosion and combustion?

Question

I think I’m being stupid or overthinking this, but if for example, you’re burning in a controlled manner, a bottle of propane in a burner producing a slow burning flame, and then you ignite the entire bottle causing it to explode, are these both examples of combustion? Is an explosion just really really rapid combustion? If so, where is the line drawn between these terms and how is the chemistry different? Or have I misunderstood these terms?

In: 5

Answer 1

Practically speaking, an explosion occurs when combustion’s expansion is fast enough to create a shockwave, or is confined to the point that over pressure ruptures or damages the containing structure or object.