5

By default, the first frame of a new particle system (with a single cell) has one particle.
If you play your project (press Space bar), additional particles are generated and emerge
from the center of the emitter.
By default, new cells emit one particle per frame in all directions (for 30-fps projects),
and each particle moves 100 pixels per second away from the emitter over a lifetime
of 5 seconds (150 frames in a 30-fps project).
Note: The Initial Number parameter in the Particle Cell Inspector allows you to change
the default behavior so a particle system begins with a burst of particles at the first
frame. For more information, see Emitter and Cell Parameters.
676 Chapter 14 Working with Particles