WOHOO, I GOT MAIL—it’s Science World's newest and most exciting toy!

Say hello to our SGA-8200 Audio Generator. This baby can pump out sine (or square) wave signals from 10 Hz to 1 MHz (1million Hertz)!

So what does that have to do with AMPED?

When someone talks, they create waves of air pressure. These waves contain areas of high and low air pressure. Measuring the number of times an area of high air pressure passes by a fixed point in a given amount of time will tell you the frequency of that sound. If a microphone is in the wave’s path, the areas of high and low air pressure will push and pull on a little piece of thin metal, often called the diaphragm inside the microphone. This diaphragm is attached to a strong magnet. This magnet is really close to a bunch of wires that exit the microphone and allow you to plug it into stuff like amplifiers. Moving a magnet near a wire will cause electricity to be produced (this is a very neat bit of physics. If you’d like to know more, please search Lenz’s law with your family). This electricity will have the same frequency as the sound the microphone picked up and it will run down the wires to whatever you’ve plugged the microphone into.

In our set up, we’ve replaced the talking person and microphone with the audio generator that’s plugged it into a speaker. This is beneficial, because our audio generator is very accurate. I can pick what frequency I want to hear and it will play it exactly.  This means that I can test all sorts of things, like how high and low the frequencies are that people can hear; or I can plug the audio generator into a speaker with a metal plate attached and make a Chladni Plate.

Download your own audio generator to your phone, tablet or computer (they’re often called tone generators) and get started trying to put a song together! I’ll give you a hint: middle C on a Piano is 261.6 Hz.  Just remember to start with the volume VERY LOW!