I recently made a short film for the Royal Institution that tells a story of the miners safety lamp, also known as the “Davy Lamp” – invented by Sir Humphry Davy in the 19th Century.
The lamp was designed to allow miners to safely light their way in the mines using candles or oil lamps – which were previously at risk of igniting flammable gases that leaked from the coal baring rocks, often leading to devastating explosions and large loss of life.
Find out more by watching the video!
This is the first time we’ve explored an archive story through the format of Andy’s Tale’s From the Prep Room series and I really like how the historical narrative is combined with the usual demonstration elements of the series – it’s something we’ll think about doing more in the future.
Riffing off the film’s subject matter, I thought I’d experiment with shooting most of the film in candle light in a pitch black environment – which was made possible by the low light capabilities of the Sony A7s, combined with a very fast vintage lens (Takumar 50mm f1.4). I really love the intimate setting that this creates and it also helped to hide the fact that we shot this in a very dull location (the Ri’s windowless basement lab used for school workshops).
Slow motion footage was captured on the Panasonic GH4 at around 100fps – watching the flames billowing out of the gas filled tube is particularly mesmerising!
I recently shot a short series of flame test films demonstrating the different coloured flames produced when burning group 1 alkali metals. The films were shot at the Royal Institution and produced for the Royal Society of Chemistry’s Learn Chemistry site.
Here’s what happens when you burn Caesium salts:
Metal salts were disolved into a methanol solution (the fuel) and this was soaked into the wireframe structures of the element symbols (Rb = Rubidium, Cs = Caesium etc.) – these were then lit to produce some really beautiful flame colours, ranging from red (Lithium) to blue (Caesium). Each element has its own unique colour or spectrum – almost like a signature colour which is directly related to its chemical properties.
Rubidium has a sort of red-violet colour:
By burning the metal ions, we’re exciting electrons causing them to move into higher energy states. These are fairly unstable states to be in so the electrons eventually move back down into lower energy states and as they do this they emit light. The wavelength and resulting spectra of light given off during this process are specific to each element (giving a range of pretty colours!) and can be used to identify different metals from one another. If you have a spectroscope (an instrument that essentially lets you look at the make-up of light) you can see the individual spectra given off by the flames.
The RSC has published some learning materials around these videos which will give you a much clearer idea of the chemistry at hand if you’re interested.
Aside from shooting pretty flames, these films also gave me opportunity to play about with titles and compositing – using the flame footage as flickering colour fills for the Element names.
I really like this effect and hope to experiment with it further in future films.
The flame test demonstrations were originally featured in the 2012 Christmas Lectures – which you can view here (around 30 mins in).