Overview and Introduction to Indoor Pyrotechnics

The lecturer opens with a lighthearted yet safety‑driven demonstration of a small indoor ice fountain, a cake-safe daytime wedding or birthday sparkler that minimizes smoke and protects the cake. The purpose is to illustrate how indoor designs are tuned to keep sparks outward and base materials from igniting unintended targets. The speaker emphasizes that indoor use requires careful consideration of size, heat, smoke production, and the surrounding environment. The audience is reminded that high-level planning and teamwork are essential; pyrotechnics is not a solo activity but a coordinated team effort responsible for safety, timing, and execution.

Footage from the British Musical Firework Championships in Southport is used to show a range of effects: flames, smoke, lighting, and colour, all integrated with music and choreography. The presenter stresses that the show must be counted down and monitored in real time, with operators ready to intervene if something diverges from the plan. The idea of “building blocks” is introduced, where effects are constructed from a set of core components and arranged into sequences to produce a cohesive visual narrative.

Fundamental Science: Combustion and the Fire Triangle

The core of the lecture centers on combustion as a science. The speaker reiterates the three essential elements needed to ignite anything: fuel, heat, and oxygen. A candle is lit using a blowtorch to demonstrate how heat initiates combustion. When oxygen is reduced by removing fresh air, the flame diminishes and goes out; when oxygen is abundant, flames become more energetic. The presenter then expands the concept to pyro devices, noting that pyrotechnics typically adjust two elements of the fire triangle: fuel and the availability of oxygen through oxidizers, enabling precise control of burn rates and effects.

The audience is introduced to a practical constraint: air in the environment is largely fixed in composition, with about 21% oxygen and the majority nitrogen. To modulate oxygen delivery in a controlled fire, oxidizers (chemical oxidants) are mixed with fuels. The speaker presents a laboratory demonstration using pure oxygen and incense to show how increased oxygen can dramatically intensify combustion, while also warning about the hazards of pure oxygen in enclosed spaces and the need to avoid uncontrolled rapid reactions.

“we need three things” is repeated as a foundational idea, emphasizing that pyro for indoor venues must stay within a careful threshold to avoid dangerous outcomes while delivering the intended effect.

Oxidizers and the Chemistry of Fire

The lecture explains how oxidizers supply oxygen to the reaction, making it possible to light pyrotechnic formulas with heat. The talk introduces potassium nitrate (KNO3), historically known as saltpetre, as one of the first oxidizers used in fireworks. When heated, the nitrate decomposes and releases oxygen that fuels the reaction. The concept of a “fire triangle” thus evolves into a broader framework that includes fuel, heat, and oxidizer, enabling designers to control the rate of combustion and the energy released by the reaction.

The speaker also highlights thousands of oxidizers and the role of solids as stable carriers of oxygen in pyrotechnic mixtures. He demonstrates how a fuel mix with oxidizers can be tailored for specific reactions and how heat is supplied to start the process, often through electrical ignition.

“this is heat, and oxidizer is our way of controlling the oxygen” - Pyrotechnician

Gunpowder, Black Powder, and Controlled Explosions

The talk moves into historical and practical aspects of gunpowder in fireworks. The speaker describes the composition of traditional black powder (approximately potassium nitrate, charcoal, and sulfur) and explains how the relative proportions decide burn characteristics. A key point is that the majority of the mixture is potassium nitrate, with charcoal and sulfur providing fuel and total energy release. He demonstrates how the powder is handled on a heatproof mat, with a delay fuse (plastic igniter cord) to achieve a controlled burn. He stresses safety and precision: even small quantities can release significant energy, and the demonstration is conducted behind safety screens with clear safety procedures.

The concept of deflagration, a subsonic combustion that releases heat rapidly, is introduced to describe how a solid like gunpowder transitions into gas during a controlled event. The audience observes the different behavior when the same chemical mixture is simply loose versus confined in a paper tube, illustrating the dramatic impact of confinement on the rate of gas production and pressure buildup.

“deflagration” - Pyrotechnician

Colour, Spectroscopy, and the Language of Light

The speaker explains how flame colours are produced by metallic salts, with specific metals emitting characteristic colours when excited by heat. The discussion introduces spectroscopy as a method to discern which elements are present and responsible for particular colours in a flame. The demonstration shows three metal salts dissolved in water and combined with alcohol as a separate fuel, keeping the colour from the fuel itself. The presenter highlights familiar colours such as red (strontium), yellow (sodium), green (barium), and blue (copper), noting how oxidation states and reaction temperatures affect the final colour. The concept of using metal salts inside a flame to achieve predictable colours is presented as a practical technique for designers to communicate mood, identity, or event branding using specific colour cues.

“particular metals that are really good at generating colour” - Pyrotechnician

Stars, Mines, and the Building Blocks of Displays

A central concept is the star, a solid particle formed from a slurry of black powder with metal salts that burns to produce a focused point of light. The ball milling process is described as a method to bind metal salts into star particles, enabling controlled burn times and predictable trajectories. The star becomes the fundamental unit in many displays, assembling into mines (a burst of stars from a single mortar) to produce rapid, dramatic eruptions that punctuate music and choreography. The discussion also touches on the design choices around colour changing effects, achieved by layering or coating stars with different salts for sequential burning as they travel through the sky.

“they’re the stars of the show” - Pyrotechnician

Pattern Creation: Choreography, Timing, and Synchronization

The lecture explains that displays are not random explosions but choreographed sequences. The speaker uses terms like slow chase, wipe across the sky, and symmetry to describe how multiple firing positions are coordinated. For larger shows, frames and banks enable complex patterns to be built, with the audience following a narrative arc as effects unfold in time. The importance of rhythm, contrast, and variation (fast bursts followed by slower sequences) is emphasized as essential to maintain engagement and avoid monotony.

Fountains, Sparks, and the Mechanics of Light

Fountains are discussed as a broad category of sparks that can be created using metal particles, compressed black powder, and a binder within a cartridge or tube. The physics of gas expansion and fluid dynamics explain how a choke at the fountain's outlet forces gas to escape at high speed, producing a dramatic jet of sparks. The speaker also introduces spark machines as a safer, controllable indoor alternative to traditional fountains, capable of rapid height changes and pulsation without smoke, making them suitable for venues like Eurovision where stage machinery must be clean and safe.

“fluid dynamics explains the behaviour of gases and liquids, particularly if they're under pressure” - Pyrotechnician

Sound, Effect Design, and Stage Safety

The use of flash powder for bright, loud effects is demonstrated, including a controlled, near-instantaneous release of energy from a small package placed in a protective fragmentation chamber. The speaker explains why containment is critical to avoid dangerous fragmentation, and how theatre practice uses a bomb tank (a safe descriptive label) to manage shrapnel and sound pressure. The demonstration underlines the difference between a bang and a pop, highlighting how human perception and safety considerations shape the choice of effect for different contexts.

“a large volume of gas being created... a fragmentation chamber” - Pyrotechnician

Airspace, Weather, and Global Regulation

The talk expands beyond the stage to discuss real-world constraints: weather, wind direction, and the proximity to airports. The speaker describes working with civil aviation authorities to ensure safety, including examples where even a short show required careful timing to avoid air traffic interference. The practicalities of outdoor performances and the often unpredictable nature of wind are presented as essential planning considerations for any professional display designer.

Conclusion: The Craft, Culture, and Future of Pyrotechnics

In closing, the presenter emphasizes that fireworks are a synthesis of science, engineering, design, and culture. The science behind combustion, colour chemistry, and gas dynamics informs artistry, while modern firing systems and computational planning enable precise, safe, and spectacular displays. The talk invites further questions and engagement from the audience, pointing toward a future where technology and traditional craft co-evolve to deliver increasingly safe, creative, and impactful pyrotechnic experiences.

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