How will my child's school handle an emergency?

I've heard the term lockdown. What is a lockdown?

When would a school go into lockdown?

What is shelter-in-place?

What if my child is riding a school bus at the time of a crisis?

How do I contact the school at a time of crisis/emergency?

How would my child know what to do in an emergency?

Will children be allowed to view events of a crisis via live television reports?

During national alerts or times of crisis, how does the district deal with field trips?

Who can pick up my child at school?