This tutorial shows how to make a set of bouncing balls using a particle system. It also takes a quick look and using particles to show force fields (a vortex).

Other tutorials will look at using the Blender particles system for hair and explosion effects.

The steps for bouncing balls are -

Move the cube up, G (grab) Z for z-axis 10
Click the Particles button, click the New button
Set Number of particles to 20
Set Start frame to 20, End frame to 40 and Lifetime to 500
Add, Mesh, UV Sphere
Move the sphere up and across, next to the cube
Select the cube, in the Render panel set the Dupli Object to the sphere
Set the size to .5 and in the Physics panel tick Size Deflect
Add, Mesh, Plane, press S (scale) 5
Click the Physics button, click the Collision button
Set the Particle Damping Factor to .2
To set the color, select the sphere, click the Material button, click the New button
Click the Diffuse color and set the green and blue values to zero

Steps for vortex are -

Click the Particles button, click the New button
Set the number of particles to 10,000
Open up the Force Field Settings panel, set Type 1 to Vortex
Tick Self Effect, set Amount to 4
In the Render panel, click Line
Move the cube up and press play

The files used in the tutorial can be downloaded from -

http://blender.freemovies.co.uk/particle-systems/