From: veritasium
The Pyro Board is an advanced, two-dimensional version of the classic Ruben’s tube, effectively creating “a whole plane of Bunsen burners” [00:01:00]. It serves as an impressive visual demonstration of sound waves and their properties, primarily applying physics in educational demonstrations [00:00:49].
Principle of Operation
Like a traditional Ruben’s tube, the Pyro Board operates by pumping a flammable gas into a chamber with numerous small holes and lighting the gas as it escapes, forming a row of flames [00:00:19]. When sounds are played into the chamber, they create standing waves within the contained gas [00:00:24].
Standing waves consist of areas where there is significant air vibration (anti-nodes) and areas where there is minimal vibration (nodes) [00:00:33]. These variations in air pressure and vibration directly affect the flow rate of the gas escaping through the holes [00:00:38], consequently altering the height of the flames [00:00:43]. The flames are highest at the anti-nodes where vibration is greatest [00:02:56]. This allows for a visual representation of the standing wave pattern [00:00:48].
Construction
The Pyro Board distinguishes itself by its scale, featuring 2,500 individual holes [00:01:02], allowing for a two-dimensional visualization of sound [00:00:56]. Its creators reasoned that “when you put on more fire, then it always gets better” [00:01:14].
Demonstration
During a demonstration, the Pyro Board is lit, revealing 2,500 small flames [00:01:07]. By adjusting the frequency of the sound played into the board, different standing wave patterns can be observed [00:01:22].
Fundamental Frequency
The lowest frequency that produces a standing wave in the board is considered the fundamental frequency [00:01:49], forming a basic, distinct pattern [00:01:57].
Varying Frequencies
As the sound frequency is increased, more complex standing wave patterns emerge, with multiple nodes and anti-nodes visible across the plane of flames [00:03:04].
Auditory Observation
An interesting phenomenon observed during demonstrations is the ability to audibly distinguish between nodes and anti-nodes. Standing in an anti-node allows one to hear the sound clearly, while moving to a node results in a noticeable reduction in sound [00:02:27]. This directly correlates with the flame heights, as flames are highest at the anti-nodes where sound pressure is greatest [00:02:56].
Music Integration
The Pyro Board can also visualize music, particularly tracks with strong bass, as the fluctuating sound waves create dynamic flame patterns [00:03:36].
Educational Outreach
The Pyro Board is used by a team of physics and chemistry demonstrators in Denmark to educate children about physics [00:05:01]. They also showcase other experimental demonstrations in physics [00:05:09].