Recently we learned about resonance, which by definition is "the tendency of a system to oscillate with greater amplitude at some frequencies than at others." This is one of the many examples of physics found within the guitar. Tuning a guitar is an example of resonance. The string's vibrations create sound waves with different frequencies. Also, when you plug in your electric guitar to the amp, you are actually making use of a physics skill! You are making a speaker. The amplifier projects the sound waves which leads to louder sound. However, these sound waves might sound a little muffled to your mom who has on earplugs. You can change the bass and the treble which alter the way your eardrums detect the sound waves. As opposed to acoustic guitars, electric guitars are electrical, so they require circuits, current, and an electrical source.