Use a tuning fork to tune the guitar

Using a tuning fork is a popular way to tune a guitar and other instruments. A tuning fork is a two prong device that has a stem and is shaped like a U. They are usually made of steel. The tuning fork gives off a certain pitch when it is struck against a surface, causing it to vibrate. The sound that comes from the tuning fork depends on the length the two prongs are.
The standard tuning fork used has the pitch of an A note. Tuning forks that emit this sound can be found easily. Tuning forks with the sound of the E note can be found easily as well and they are very useful for guitars. Tuning forks are cheap and easy to bring along with you.
When using a tuning fork, hold the fork by the stem so that the prongs can vibrate freely. Strike the prongs hard enough so that they begin to vibrate. Be sure not to strike them on anything that will dent. It is best to strike the fork against your knee. Not too hard of course! After that and without touching the prongs, place the stem lightly on the guitar body. Now tune the string to match the sound that comes from the guitar.
In order to use a tuning fork properly you will need to practice. It may be hard for a young player and a guitar player with experience will not want to carry around different tuning forks.