Sound is a vibration that travels through air, water or even solids. When you transfer the vibration from the pin to, for example, a cup, you create a simple amplifier.
Normally, sound enters your ears. From there, it travels to your inner ear via many different routes. But you can also skip a few steps and “hear directly through your bones”. This is called bone conduction. Roll up your sleeve and put your elbow on the pin. Now press your hand flat against your ear and listen to the beat.
Bone conduction in headphones
There are headphones or hearing aids that you don’t put on your ears, but on your skull.
Bone conduction in elephants
African elephants can talk through the ground! They make low, rumbling sounds that are barely audible to humans. Their sound vibrations also make the ground tremble.
Kilometres away, fellow elephants ‘listen’ to the ground with their feet. Via bone conduction, the vibrations travel from their toes to their feet and then all the way to their ears.
Bone conduction for advertising
Do you ever rest your head against the window on a train? Peaceful, right?… Or is it? A German company tested whether they could transmit advertising messages via vibrations in the window. Bye bye naps!
