How do can telephones work

Talking causes little vibrations in the air in front of your mouth, as you can tell by speaking into your hand. When you send those vibrations into the can, they cause the back end to vibrate. This vibration is passed along the string and into the other can.

When that can vibrates, it creates vibrations in the air once again and you can hear the other person's voice! Give Now ». Noon Edition. Home Archives About Contact. Can You Hear Me Now? By William Orem Posted May 26, In an old-style telephone, the person speaking vibrates a metal diaphragm.

The diaphragm's vibrations rapidly compress and uncompressed carbon granules, changing their resistance. A current passing through the granules is strengthened or lessened by the changing resistance.

At the other end, the rapidly changing current runs through a speaker and causes its diaphragm to vibrate back and forth, so the second person hears the first person speaking. See How Telephones Work for details. In a radio, the changing current from the microphone is used to modulate a radio transmitter. The modulations are sent through the air to a radio receiver, which turns the modulations into the vibrations of a speaker, and the second person hears the first person speaking.

In a compact disc or a cassette tape , the sound waves vibrate the microphone and the vibrations are recorded on the tape or CD. In the tape, they are stored as magnetic fields in iron oxide. On a CD the vibrations are digitized and then written onto the face of the CD. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Physical Science. It has to do with how the particles are packed together.

In gases, molecules are very spaced out, so vibrations take longer to bounce between them. In liquids, the molecules are closer, but not super closely spaced. Because of this, sound travels faster since the vibrations can bounce more readily. In solids, where sound travels the fastest, the molecules are packed extremely tightly with little space between. This way, the sound vibrations can easily bounce through from one side to the other with little space to jump. What you need: Two tin cans with their tops removed Duct tape Nail Hammer Up to 10 ft long string Craft supplies to decorate What you do: First, cover the sharp edges around the open side of the can with the duct tape.

Try a different length of string. Can you hear one another better or worse or is it the same? Would you be able to hear each other around a corner? Why it works: Sound travels through waves and vibrations.