What is the Science of an Explosion?

Last week's tragic explosion in Royal Oak, which took the life of , left many residents with unanswered questions, including, "How did this happen?"

As Consumers Energy continues its door-to-door outreach today—listening to residents' concerns and answering questions—we asked Royal Oak High School physics teacher Kristen Elsner to explain the science of an explosion.

What is the science of an explosion?

Elsner: An explosion occurs when stored energy is released very quickly. This release of stored energy does work on the object.  This means that a force is exerted for a distance on the object.  The force is actually radiating outward from the site of the energy release, so there will be many points of forces radiating outward on the object, which will tear it apart into many pieces, obeying the Law of Conservation of Momentum.  The initial speed and potential distance the pieces fly depends on the mass of the piece.  The more massive, the lower the initial speed that it will have, and the less distance it can cover. A lighter object will have a higher velocity and could travel farther, depending on drag.

Why does it make a loud noise? 

Elsner: The sudden release of energy also creates a sudden increase in pressure. This compression creates a sound wave.  The larger the rate of energy release, the higher the compression and the louder the sound. Extremely high pressures created by bombs can create blast waves and shock waves that can cause structural damage and bodily harm, even death. The shock wave from the recent Russian meteor shattered windows.  

Why do windows blow out?

Elsner: When this sudden release of pressure occurs it can create a vacuum in its wake, causing a rush of air to fill the void, causing pulling effect rather than the pushing effect of the initial blast, "sucking" out windows. While the shock wave produced by the explosion causes damage, the shrapnel from the explosion is often more detrimental.

As for the cause of the explosion, "preliminary testing has determined that a gas service line to the house was damaged and was the possible cause of the explosion," according to a Consumers Energy statement.