hi, I would like to know about headphones. 
Headphones which are worn over the ears allow people to listen to audio privately without disturbing others
really, how do they accomplish that?
They convert electronic signals to sound. They're pretty cool!
oh my. I would have never guessed. Are there different types of headphones? 
Yes! You can use earbuds to plug inside your ears, instead of over your ears
wow, I wonder when those first came about...
I think around the time of the radio revolution. When it was trendy
oh, I guess that makes sence.
headphone and microphone. Headphones connect to a signal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video game console, or electronic musical instrument, either directly using a cord, or using wireless technology such as Bluetooth, DECT or FM radio. The first headphones were developed in the late 19th century for use by telephone operators, to keep their hands free. Initially the audio quality was mediocre and a step forward was the invention of high fidelity headphones.
Headphones are made
Headphones
Headphones (or head-phones in the early days of telephony and radio) traditionally refer to a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earspeakers, earphones or, colloquially, cans. Circumaural (