What Is Plasma Ball and How Does It Work?

The plasma ball is a small glass ball that is filled with lightning that you can control. You can find them in novelty shops, and they are very interesting to watch. But have you wondered how do they work?

There is more than what meets the eye. It's not just a toy. The physics behind it is pretty interesting. The plasma ball is also called a plasma lamp or globe depending on the shape is a glass container that filled with a high voltage electrode and a mixture of different noble gases.

What Is A Plasma Ball?

Here is a quick lowdown on how plasma ball works. It has two glass spheres, and the inner one has a high automation voltage running through it, and the outer incases all the air inside the globe.

The high alternating voltage strips the electrons from the atoms that produce a lot of heat and forms a plasma. The heat can be demonstrated by how the tendril rises.

It's also responsible for the photon emission that calls excitation and deexcitation of the electrons in the atoms. The type of gas present in the sphere, as well as the energies, dictates what color it forms.

You can actually buy different colored globes. That is what makes this a fun toy to have. The one that you can buy from the store won't electrocute you. You won't even feel any sting.

All they do is get slightly warm, and that's what makes them perfectly safe enough to give to a young kid. They also make for a good Christmas present.

Physics of A Plasma Ball & How It Works

Now, if you don't understand any of the above scientific stuff, don't worry. We all have skipped physics classes a few times. Now, I will try to explain how the physics work and hopefully in a way that won't make you fall asleep.

Have you ever noticed that when you put your finger on the top glass, it attracts the stream? If you put multiple fingers on, it will not only attract streams of light but will also make your fingertips glow.

Now, the question is, what is going on? Well, stay tuned. In this article, I'm going to explain how a plasma ball works.

Components of A Plasma Ball

The first thing you will notice is that there are a couple of components that make a plasma ball. The center tube is called the Tesla coil, and you have the glass dome on the top.

It is filled with a number of noble gases. The predominant is Neon, but there can be Argon, Xenon & Krypton. The tesla coil produces a high voltage AC supply, which is in the order of 2 to 5kV.

The frequency is in the order of about 35kHz. A high potential difference is being developed in the center, and the potential is going to be significantly lower at the edges.

Which means you are getting a potential difference between the inner and the outer dome.

How Does Plasma Ball Work? 

It produces a radio frequency electromagnetic wave. In simple terms, you are getting a radio wave that is emanating out of the tesla coil. If you didn't know, radio waves could cause electrons to move.

For example, a radio wave in a metal wire will cause the electrons to move quickly. In fact, radio antennas work on that very principle. You are experiencing radio waves now, but those electrons are particularly tightly bound, and they are generally not going to move a lot.

So, what about the material that you are seeing? Well, the radio wave that is being emanated out is actually quite high in energy. As a result, it causes the gases here to ionize.

Now, what do I mean by ionizing?

Well, ionize, in essence, is that the electrons are being ripped off the atoms of the Neon, argon, xenon, and Krypton. Now that means the atoms in here are not in their neutral state.

They're separated into their positive nuclei and their negative charges as they're being ripped off. Now that, in essence, refers to the fourth state of matter, and that is plasma.

Plasma is, in essence, a gas that has received so much energy, a fair amount of the atoms loses their electrons. As they lose their electrons, we now have a sea of charged particles.

In fact, most of the universe is plasma, and so although we see the effect of plasma in this tone, other examples of plasma can be seen, for example, in terms of lightning when we look at an example nebula in astronomical images and so forth.

Why do we get these streaming effects?

Well, because we have this potential difference from the inner dome to the outer dome, we have electrons wanting to move to the outer dome.

So, we have a flow of electrons. But those electrons aren't always loose. They often jump in and out from their atom.

As photons pop in and out, they release light. And so you have these streams of electrons popping in and popping out moving from the high potential to the lower potential, and they will heat up the gas and cause the gas to emanate light as they emit photons on and off as they stream out.

So, that, in essence, is what causes these tendrils of plasmas. These electrons moving from the inner dome to the outer dome, but in the process, they're going to be releasing light, and the light is actually unique to the elements.

Why do they change color?

If we were to do a spectral analysis of the light, in other words, break the light up into its individual frequencies from let's say spectroscopy, then you have a particular signature of frequencies, and those signatures are unique to the elements that we have in here.

So, the colors here are indicative of the elements that we have in this dome. But not only do these electrons emanate from here, at the glass level, what we have is the glass is sort of what we refer to as a dielectric.

So, these electrons go across they continue streaming off the glass as they interact with the glass, you don't see anything coming off there, but they are coming off.

So, if we could concentrate them, then we might see some reaction some sparking.

Where are these electrons going?

Ultimately these electrons are trying to get to the neutral position. So, if we touch the dome, you will get this really strong stream of plasma going to the top. Now, why is that?

Well, you are connected to the ground, and so these electrons are going to have a much easier path going to you than just into the air.

And so, we get a lot more flow of charge going through this stream. Now, there's another factor going on here. Apart from the fact you are providing an easier path for the electrons to get to the ground and basically move from the very high potential level to the low in magnitude.

We're also going to see that this stream is a lot tighter. Now one of the interesting factors here is that this stream of electrons develops its own magnetic field.

And so, what we get here is what we refer to as magnetic focusing. And so not only is this stream brighter because we have more charges flowing, but we also have a narrowing of this line, so it's much stronger.

But notice how it is quite strong. Now, what would happen if you were to touch on the side?

Why is the behavior different? 

Well, we're going to do that and demonstrate that not only is this bright in light, but this is also high in energy in terms of heat.

So, when you touch at the side, you will notice how the streams arc to your fingers, but then they rise up and break and come back to this position. Why?

Now, the thing is, these streams are hot, and as you are aware, hot air rises. So, the temperature is going to increase, taking the filament along as the tip as it rises, but then the length is so long, they do eventually break that cycle. And it starts at the zero position.

Why don't you see the tendrils?

Now, the last question is, why do not we see the tendrils outside?

Well, it has to do with atmospheric pressure. The outside has a pressure of let's say one atmosphere, but it's considerably lower than one atmosphere on the inside, and that's why these tendrils can develop because these gases actually are at low-pressure.


So, there you have it. Now you know how a plasma ball works and what it does. Don't worry, the ones that you buy as a toy are very safe, and they are great to buy as a Christmas gift. It's also a great way to introduce your child to physics and science.

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