Technique · Fields
Atom model
A glossy nucleus of packed spheres circled by thin elliptical wire orbits and shiny electrons, in soft focus over a colour gradient.
Atom model is a field drawn for every pixel by the graphics chip. Every piece on Synapse Drip is made from a recipe that layers techniques like this one, and you can change any of it in the Studio.
Good to know
- Niels Bohr's model of 1913 put electrons on fixed circular orbits and explained the spectrum of hydrogen; the picture of rings round a nucleus became the symbol of atomic energy.
- The Fibonacci spiral that packs the spheres is the pattern of seeds in a sunflower head, 137.5 degrees apart.
- An atom is a few tenths of a nanometre across, and its nucleus is about a hundred thousand times smaller: if the nucleus were a marble, the atom around it would be roughly a kilometre wide.
- In Ernest Rutherford's model of 1911 an atom is mostly empty space: nearly all its mass sits in a nucleus about a hundred thousand times smaller than the atom itself.
- The nucleus is made of protons and neutrons, which are themselves built from quarks held together by the strong force; the colourful balls in pictures like this are a diagram, not a photograph.
The mathematics
- The 48 nucleus spheres are placed at height z = 1 - 2 (i + 0.5) / n and angle i times the golden angle, 2.3999 radians: every sphere gets about the same area of the ball, so none is crowded.
- An orbit is an ellipse in a randomly tilted plane; the electron's position is the ellipse's semi-axes times (cos psi, sin psi), which is the shape of a Keplerian orbit, though here the ellipse is centred on the nucleus rather than having it at one focus.
- A tube round an ellipse is the distance to the ellipse minus a radius: the field is built from the ellipse equation (x / a)^2 + (y / b)^2 = 1 and the height z above its plane.
- The square glints on the spheres are the reflection of a rectangular softbox, found by reflecting the view ray about the surface normal and testing where it lands in the light's rectangle.
In art
- In the 1950s the orbiting-electron symbol turned up on fabrics, furniture and diner signs, a style now called atomic age design.
- Soft focus, with a sharp subject in front of a blurred background, is borrowed from photography to give a computer-made scene a camera's sense of depth.
More ways to use it
Related techniques
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