Tesla Coils are Cool
By Emily Dennis, @emilyjanedennis
I watch a lot of hockey.
As a Detroit Red Wings fan, I know that The Joe is the best hockey rink: it has the best music, the best zamboni guy, the best octopi traditions, and the best players. So, I can’t believe I’m saying this, but the Tampa Bay Lightning has the best goal-celebration in sports. Whenever the amazing Steven Stamkos or one of his teammates score a goal, this happens:
That is a Tesla coil.
The Tesla coil is named after its inventor, Nikola Tesla. In the late 1800s, Tesla and Thomas Edison were both working on competing forms of electricity. Tesla worked on alternating current (AC), a current that changes direction at an imperceptible speed: 60 times a second! Edison invented a device to supply direct current (DC) power, the kind of power that flows in one direction, like a battery.
Lucky for us, Tesla won this “War of Currents” and we now have AC power in our homes. DC power isn’t as good for our modern needs because the farther it travels, the less efficient it gets. It’s also significantly harder to increase and decrease the voltage of DC power than AC power. AC power allows the electricity companies to produce tons and tons of high voltage power, send it through high-voltage wires to transformers, and then turn that power into the lower voltage that we use in our homes.
Tesla knew how important and ubiquitous it would be in the future and he wanted to find a way to transmit it wirelessly, like wifi for charging electronic devices. To do this, he invented the Tesla coil. Unfortunately, Tesla coils are dangerous and much more difficult than getting power through power lines, but they can power lights wirelessly:
The Tesla coil works by taking the electricity that we have in our homes (120 volts of AC power) and turning it into 1,200-1.5 million volts that also alternate way faster than our normal AC power. The details of this process can be found here and here, but basically a Tesla coil charges up a metal circle on top of the device and then sends that charge out into the air or to a nearby piece of metal.
This is like a really strong and dangerous version of the static shock you can get from walking on a rug in the winter with socks on, and then touching metal… but the shock in the Tesla coil is so big and fast that we can actually see it. Because the sparks are so “humongous big” that Tesla coils can be used do things like this:
These coils are sparking lots and lots of times each second. Each time the coil sparks, it pushes the air, which vibrates the insides of our ears. If it sparks 300 times each second, your ear receives 300 waves per second, and it sounds like this (humans can hear between roughly 20 to 20,000 waves per second). By changing the number of sparks every second, you can hear different tones that make up the song!
Tesla coils aren’t just for fun. Researchers use Tesla coils to study lightning and its effects on buildings, people, and animals. Even though we’ve been rigorously studying and experimenting with it since Ben Franklin, we still have no idea how exactly lightning begins to form in the clouds. Studying lightning is hard because we don’t know when or where it will strike. This means that we don’t know where to point our instruments to take measurements. Today, we actually use a high-tech version of Ben Franklin’s original key on a kite experiment: we send rockets coupled to tiny copper wires into thunderclouds to encourage lightning to strike in a somewhat predictable place. This allows us to orient our measuring devices to the right spot and get really accurate recordings of exactly what is happening.
We may not know exactly how lightning starts, but there are plenty of hypotheses currently being tested. One newer theory proposes that lightning emerges from the interaction of charged clouds with energy from space, like gamma rays. Using satellites equipped with high-tech measuring devices, together with rockets to draw the lightning to a certain spot, researchers may finally be able to see if there is a correlation between gamma rays and lightning strikes.
- Watch the Tampa Bay Lightning play tonight! on at 7:30 pm vs division rivals, the Florida Panthers
- Read a billion amazing NHL puns on @NHLBlinn‘s tumblr!
- Read more here about how people produce songs and sounds with Tesla coils.
- Learn how people build Tesla coils (super dangerous!) http://www.instructables.com/id/How-to-build-a-Tesla-Coil/
- Visit the most powerful Tesla coil in the world
- Visit How Stuff Works to find a lot of good info on electricity, including induction and electromagnets
- Listen to an NPR interview with a lightning researcher from Florida
- Check out the cool photos and info from Florida Institute of Technology
- Look at NASA’s informative website on lightning and lightning research