Resonance means the build up of
vibrations of an object when it is vibrated at a certain frequency.
Objects can be
made to vibrate when you push them in some way. Think about pushing a child sitting on a
swing. You will find that as you push the swing will only swing further and further if you push
at one certain rate. At any other rate and the swing's motion is irregular, it comes back and
hits you as you are about to push again.
The only way to get the vibrations to build
up is to push IN TIME with the swing's own rate of swing. To put it another way the frequency
of your pushes must be the same as the frequency of the swing's movement.
The
swing's own vibration frequency is called the natural frequency and the frequency of your
pushes is called the driver frequency.
Resonance occurs when the driver frequency
is equal to the natural frequency of the object