Parabolic Reflector

Parabola vs. sphere
If cross-sections of a spherical surface and a parabolic surface were made by slicing each surface in half, these would be the shapes you would see:

I've been wanting to make a parabolic reflector for quite some time now.

As I have heard more and more about them, from Marcus Coates using them to record specific birds in trees for his work 'morning call' and Chris Watson amongst various other sound artists mentioning them on several occasions, I thought it would be worth checking out what all the fuss is about.

I managed to find these instrucions of how to make a parabolic reflector on Instuctables. It also gives a dxf. file which is excelent as I could use this for the Laser cutter machine they have here at Bezalel.

There is also a rather good link to youtube on this page, showing a parabolic reflector being used to cook some bread and fry something (not sure what exactly).

And here is a very useful Java tool for anyone who might be wandering about how to calculate the radius of a parabola, according to it's length and therefore find the focal point - Equation of Parabola.

I was originally going to make a concrete parabola, something like what they used on the coast of britain to detect incoming aeroplanes during the war, using a large inflatable exercise ball.

However, after some research I realised that I had made one of the fundamental misconceptions - that a parabolic dish is part of a sphere. It is not. It is part of a paraboloid.

If you slice a cone with a plane that is parallel to a line on the cone through its vertex (such as UV on this figure), the intersection is a parabola. Here is a proof of this fact.

Interpretation & Reflection

Interpretation

I decided to choose oobleck for it's enigmatic qualities and it's reluctance to conform to classification as any one state of being and could be a metaphor for creative ability.

The random scattering of words on the satellite is a reference to Hugo Ball's 'word salad' form of poetry, breaking down the structures of language.

The satellite dish is a symbol for the repressive powers who manage to filter out some of the work being produced by artists but the majority of it carries on regardless.

The briefcase has an obvious reference to travel and how many people had been exiled, abroad or to concentration camps. However in this case it is a point of collection which is then focused down through the opening and along the gutter.

The vinyl is then not only a means of expression through music but is a further means of creating something new and unpredictable by spattering the mixture around again.

Reflection

Although initiated by myself the work then left to become very much in the realm of the audience. Their reaction on the opening night was one of curiosity, because of the viscosity of the mixture the process was quite drawn out and the audience feel quite for the good part of ten minutes almost expecting something spectacular to happen. It seemed like it was a nice focal point for people to talk about or even just to talk about something completely unrelated whilst still observing the unravelling of the piece.