1. Dirty Bombs
Steven
Ivan
Zoe
Tim

2. What is a dirty bomb?
A dirty bomb is a weapon that’s purpose is to create psychological, not physical, harm through mass panic and terror. Because of this, dirty bombs are sometimes called "weapons of mass disruption".
They are used to spread dangerous and radioactive materials over a large area.

3. Has a dirty bomb ever been detonated?
A dirty bomb has never been used to date, but there have been scares of the possible use of one on the United States.  Many crowded places, such as Logan Airport in Boston, go through tests in case such a thing might happen.
On May 8, 2002 Jose Padilla, a member of Al- Qaeda, was arrested because he was suspected on planning a dirty bomb attack on the United States.  

4. What isotopes are likely to be used in a dirty bomb?
Some isotopes that would be likely to be used in a dirty bomb would be caesium-137, cobalt-60, and iridium-192. This is because they emit gamma rays.
Some potential sources of dangerous isotopes are Francium, Uranium, Thorium, Plutonium, Neptunium,  and Radium.