HOW CAN A WIZARD MAKE GREAT BALLS OF FIRE?

Fire. The holy grail for early humans. Prometheus was said to steal it from the gods to benefit mankind, but however we came across it, once we discovered how to make it, the world changed. We went from maintaining naturally occurring fires caused by things like lightning strikes or volcanic activity, to working out how to rub sticks together or strike a rock to ignite some tinder. Now, we can just use matches or grab a lighter, but to ancient humans, these devices would appear as magical as someone proclaiming “Incendio” or “lacarnum inflamare” to send flames flying from the tip of a magically modified stick. So, how could a wizard create a fireball from a wand?

A Recipe for Combustion

Fire is the result of a chemical reaction called combustion. In combustion reactions, substances react together, resulting in the production of new substances. Heat and light are given off in the process. A reaction that gives off heat is called an exothermic reaction. Therefore, combustion is exothermic.

In the majority of combustion reactions, an oxidizer reacts with a substance (the fuel) when presented with enough thermal energy, i.e., heat. An oxidizer is basically a substance that takes electrons from the substance it is reacting with, i.e., the fuel. On Earth, the most common oxidizer in combustion reactions is oxygen, as it’s widely available, making up 21 percent of the air we breathe. Other possible oxidizers that can lead to combustion include fluorine or chlorine gas.

The creation of fire on Earth generally requires the presence of three ingredients; fuel, heat, and oxygen. These are commonly referred to as the fire triangle. If any one of these elements is lacking, combustion won’t occur, and no fire can be made. So, for a wizard to successfully conjure a flame from the end of their wand, all three parts of the fire triangle must be present. Since Harry Potter takes place on Earth, the oxygen part is covered. However, if in a place with very little or no free oxygen, the wand would need to produce its own oxidizer. This is how rockets work in space. The fuel they use contains its own oxidizer, allowing rockets to burn in the vacuum of space even though there’s no oxygen. For our purposes, we’ll only be considering environments where there is sufficient oxygen, so the trick is in working out how to create combustion with a wand.

Fire Wands

A wand is seen as a way for a witch or wizard to channel their magical prowess. Each one is made from a particular type of wood and contains a magical core that affects how the wand behaves. But how could a wand manipulate oxygen, fuel, and heat to create fire?

In the muggle world, lighters are a common way to make a flame and have been around in various forms for more than a century. They work by igniting a fuel in the presence of oxygen. It’s not hard to make a lighter in the shape of a wand; BBQ lighters can be especially long already, and products described as wand lighters actually exist. Of course, a wand can do so much more than just make a flame, so filling a wand with a lighter fluid such as butane or naphtha wouldn’t leave much room for other functions. It’s a start, though.

If you take a transparent disposable lighter, you can see that it contains liquid fuel. This liquid is just a gas under lots of pressure. Generally, if gases are compressed enough they will become a liquid. A gas can also become a liquid if it’s cooled sufficiently, and if it’s cooled even more, it can freeze into a solid. A fuel will take up less space as a liquid or solid and so any fuel source held in a wand would be stored more efficiently in one of those states.

We’re surrounded by fuels that are in solid, liquid, or gas states. Solid fuels include coal and wood, but they don’t actually combust straight into a flame. When they get hot enough, they undergo a reaction called endothermic pyrolysis, which produces flammable gases. It’s these gases that can then combust to produce light and heat. This heat feeds back into the process as part of a chain reaction, which is another important part of fire propagation. So much so that it’s now often included with the three elements of the fire triangle to form what’s referred to as the fire tetrahedron. So, how could a wand achieve this?

Considering that the outside of a wand is made of wood, there’s always the possibility that it could set alight. Having said that, combusting a bit of the wand itself could technically be a solution to fueling a fire, but this would vastly limit the amount of fireballs that could be produced before the wand was burnt up, leaving a charred black stick that would be brittle as well as messy. This is clearly not an option, so what fuels could a wand conjure to make fire?

Fueling the Fire

When solid fuels are heated, they undergo changes that release combustible gas. Liquid fuels work in a similar way in that when they’re heated they evaporate into a flammable gas that is then combusted. So really, regardless of the initial state, combustion generally occurs using flammable gases, like the fuel in a fire triangle or tetrahedron.

Among other things such as available oxygen and air pressure, the particular fuel being burnt can have an effect on the temperature of the resulting flames. This is important because some objects need more heat to be set alight. So, a lower temperature flame from something like animal fat or kerosene would need to be bigger or applied longer than a higher temperature flame from a fuel mixture like oxyacetylene.

Muggle magicians often make fireballs, and they have different methods to produce them. One example uses a flammable solid material that’s basically cotton wool but supercharged. It’s called nitrocellulose or flash cotton, and when it’s burnt it produces a flame that is literally gone in a flash. The diffusion of cotton wool allows oxygen to reach the sites of combustion more easily, making the reaction happen a lot quicker. There’s a small product out on the market called Pyro Mini Fireshooter that launches fireballs in this way, but from a smaller unit. A problem with this technique is that it burns so quickly that it wouldn’t pass a great deal of heat to whatever it comes into contact with. It’s the reason why show people are so content with setting light to their bare palms. It also means that Hermione couldn’t use it to set light to Snape’s cloak. So, what other methods are there?

The spraying or ejection of liquid fuels could also be employed. A stream of flammable liquid can carry a flame a lot further than a gas fuel can. These liquid fuels can also more readily land on objects and continue burning, especially if they are thickened; such was the case with napalm. Most flamethrowers used in World War II and the Vietnam War operated in this manner.

If a wand was loaded with a bit of liquid fuel, it would also need a way to propel it. It could use a pressurized gas as the propellant (which is how flamethrowers do it) or be mechanically squirted out by squeezing the base of the wand. Both of these methods would work, but the resulting flame would look more like a stream of flame rather than a fireball, which leaves gases, of which methods are various.

A wand could contain compressed gas fuels as liquids. This wouldn’t take up much space and could provide a few good burns for a small fuel payload. Reactions could also happen within the wand to create gases. One such example is calcium carbide, which reacts with water to produce the flammable acetylene gas. In this way, the wand just needs a chamber to contain the calcium carbide, and the ability to add water to it at will. The pressure of the gas could build up and be released as a puff, which once ignited could provide a small fireball. Regardless of the fuel type and method of release, all of these methods rely on a sufficient source of heat for ignition, so how could that be done?

Generating Heat

Lighters have various methods of ignition to provide the necessary heat energy for combustion of the fuel and oxygen mixture. The most common method uses a spark from a rock or metal such as ferrocerium i.e. lighter flint. The drawback with the flint is that it requires mechanical action to create the spark, which would have to somehow happen within the wand. The same is true with using an electric discharge from a squeezed piezo electric crystal; something found in many lighters. In this type of lighter, an electric arc is generated between two electrodes when sufficient voltage is applied.

There are also catalytic lighters which use an alcohol like methanol in the presence of a platinum catalyst. A catalyst is a substance that allows a reaction to happen faster or with a lower input of energy, but isn’t used up itself in the process. As the methanol vapor comes into contact with the platinum, a chemical reaction occurs, which generates heat. This heat is enough to initiate combustion in the methanol. This would be a compact and easy enough way to fit a lighting mechanism onto the tip of the wand, and a pressurized gas again would allow a flame to be propelled from the tip rather than just emanating from it.

Another possible option is to use what’s called hypergolic fuels. With these, two substances come into contact with each other and undergo a reaction that causes them to combust without the need for a separate ignition source. These are frequently used in space flight. As far back as the Apollo missions, the fuels Aerozine 50 and nitrogen tetroxide were used in the engines of the service and lunar modules.

Great Balls of Fire

So, it is possible to create a fireball, providing all elements of the fire triangle are present. Fitting these within a wand is the issue. Using gas as a fuel could produce a nice fireball as could any reaction that produces a significant volume of flammable gas. The fuels could only be stored in small quantities, though. To provide the heat for the reaction, hypergolic fuels are possibly the most straightforward method, but ignition via catalysis also seems like a good way to achieve a flame on the tip of a wand. Either way, a fire-producing wand is well within the reach of real science and technology.