Resonance

=** Resonance**=

Resonance is when one object vibrating at the same frequency as another object forces the other object to vibrate.

The word resonance stems from Latin. It means to "resound" – to make a loud sound together.

An example of resonance is hearing the sound of the ocean in a seashell. When you put your ear up to the seashell you think you are hearing sound from inside the shell but you are actually hearing low intensity sounds from the area you are in. This background noise causes vibrations in the seashell. But the seashell itself has its own frequency, and if the noise in the room has the same frequency it will cause the seashell to vibrate, which is an example of resonance.

3 Conditions of Resonance

1. Objects with Natural Frequency: The natural frequency of an object is the frequency at which the object oscillates. Also object can have harmonics, which is when the object has more than one natural frequency. An example of this is a guitar. A guitar string sounds the way it does due to multiple harmonics on the string.

2. A Forcing Function at the Same Frequency as the Natural Frequency: In mechanical systems and electronic circuits the forcing function does work on an object. Because work is a form of transferring energy, there is now more energy in the object.

3. A Lack of Damping or Energy Loss: For an object to have resonance, energy must build up in an object. Damping is a way to remove energy from the object by changing it to heat. Some examples of things that cause damping are; friction, air resistance, and viscous drag. Electrical resistance performs the same function in electronic circuits. Some other ways of energy loss can be sound (instruments) or light emissions (lasers).

In the video below, we see an example of resonance when one of the rods is flicked it causes the rod with the same frequency to vibrate also. The other rods are not supposed to vibrate but they do a little bit in the video. media type="file" key="resonance.mov" align="center" width="300" height="300" Sources: 1. http://www.intuitor.com/resonance/index.php 2. http://www.physicsclassroom.com/class/sound/u11l5a.cfm