We know child seats are important, but do we know why?  How do they work to keep our children safer in a car accident, and why is it so vitally important that they be installed correctly?

It helps to first examine how seat belts work.  There's an old saying in injury analysis -- "it's not how fast you're going, but how fast you stop,"  meaning injuries occur not because you are traveling fast, but because you stop incredibly quickly (like under a tenth of a second).  To give an obvious example of this, a passenger jet lands at something like 150 mph, and everyone is fine because it comes to a stop over a relatively long period of time.  If that same jet crashes into the ground at the same speed, everyone dies instantly. The difference is the time period over which the plane stops.

So let's apply this to seat belts and child safety seats.  Let's say John runs his car into a wall at 50 mph, and is stupid enough to not be wearing a seat belt.  John's car stops in the blink of an eye, but poor John keeps moving at 50 mph . . . until he hits the windshield with his head (for all of you smart alecks out there - his car didn't have an airbag).  John has bought himself a ticket to the morgue, because his skull couldn't withstand those forces.