Editing Tesla Coil (section)

== Why This Works ==

The Tesla Coil was invented by Nikola Tesla, a scientist in the late 19th and early 20th centuries. The device is a way to see how a charge can be built up and made larger by use of what we call ''Transformers''. A transformer is pretty simple overall: You set up two coils, with one inside the other, like the Tesla Coil. Then, you run a charge through one of the coils. The size of the coils affect the outcome you get; That is, if one coil is bigger than the other, then you will get a ''different charge'' out of the second coil. In this case, we run a charge through the smaller coil, which means the larger one will generate a larger charge. This is known as a ''Step-up Transformer'', since we are "stepping up" the voltage. Likewise, if we ran the charge through the big coil instead, the small coil would give a smaller charge, resulting in a ''Step-down Transformer''. 

In our circuit, we start with the voltage from a wall outlet and send it through a step-up transformer, which boosts the voltage by a factor of 50. It then sends the charge to the capacitors in the circuit. ''Capacitors'' are, simply put, a set of metal plates that are really close to each other, with only a tiny amount of space between them. These gaps will hold a charge, making a capacitor something similar to a battery. Unlike a battery, a capacitor doesn't slowly discharge; it empties ''all the charge it has at once'', which gives a boost to the voltage by a factor of 10. From here, the circuit goes into our Tesla coil's outer, smaller coil, which acts like a second step-up transformer, which boosts the voltage by a factor of 100. In the end, the entire system will take in the wall voltage and can multiply it by as much as 50,000!

The output of the system is controlled by what is called a ''Spark Gap''. The spark gap is our adjustable resistance for the system, and controls how big the bolt can get. If we leave it closed, the bolt cannot get big, and might not even be visible. As we widen the spark gap, the bolt will grow bigger, with a ratio of about 10:1. That is, for every inch the spark gap opens, the bolt can fire an extra 10 inches! The maximum possible output of the system is controlled by the spark gap, which greatly limits the actual output of the system. Since it is open to the air, the copper tips of the spark gap quickly oxidize while the Tesla coil is running. This rapid oxidation makes it harder for the spark gap to conduct, and needs to be removed between runs to allow the coil to run.

When we see the bolt, we are actually looking at ''Plasma'', the fourth state of matter. We don't often encounter plasma in our day-to-day lives, but it is the most common state of matter in our universe! Plasma is when you excite a gas so much that it gets super hot, and the electrons start flying around it really fast, no longer staying with their original atoms or molecules. The color of the bolt, the blue-purple color, is because of the gas in the air being so excited. Notably, it is oxygen gas, since nitrogen gives off a white light when excited. Oxygen gives off a blue-purple color when it is excited. This is a different reason for why the sky is blue, however, since our sky and air is all gases, and not made of plasma! Lastly, the smell you might notice is a result of this oxygen plasma. When the oxygen atoms got all excited, some of them split and recombine not as O<sub>2</sub>, the oxygen we breathe, but as O<sub>3</sub>, which is known as ''ozone''.