What is matter?
What is energy?
What is light?
Curious minds have asked these questions since ancient times.
So begins our Radiant Matter installation for Rutherford's Den. Featured as a centrepiece of the new space, the installation creates an immersive space in which to experience historical ideas about the nature of light, matter and energy.
The installation was conceived around the centrality of Rutherford’s Gold Foil Experiment to the expansion of human knowledge about atomic structure.
Upon entering the space of a 'Cylindrical Volume', the visitor encounters a series of abstract visualisations of particle relationships and associated light conditions. These visualisations will present different atomic conditions as they were understood historically.
Users can interact with the exhibit to create the sense of 'rays' hitting the central nucleus of the atom, just as Rutherford had first perceived them in his Gold Foil Experiment in which he first discerned the nuclear structure of the atom.
While many of these ideas and concepts were later superseded, these historical conceptualisations were central to the development of quantum physics and, in turn, the innovations of our modern world.
Executive Producer: Sarah Barns, Esem Projects
Art Director: Michael Killalea, Esem Projects
Digital Design and Development: Code on Canvas
Sound: Gary Sinclair, Tactile Music
Commissioned by the Arts Centre of Christchurch for Rutherford's Den.
The 1911 ‘Gold Foil Experiment’ led by Rutherford, and performed by Hans Geiger and Ernest Marsden, confirmed the structure of every atom as being built around a tightly concentrated mass that is positively-charged.
Preceding this discovery of atomic nuclei was J.J. Thomson’s discovery of the electron in 1897, which opened the way for interrogations of the structure of the atom not as the smallest building block of nature, but as a field of composite particles.
As Rutherford conceived, electrons must orbit the dense nucleus like planets around the sun. This was quickly proved incorrect by Niehls Bohr, who argued that the orbiting electron around a positively-charged nucleus would be an unstable atom. According to the physics of electromagnetism, the orbiting electron should spiral into the nucleus, making an atom unstable.
Addressing the structure of a hydrogen atom, containing just one electron, Bohr proposed that the orbiting electron was in fact ‘quantised’, meaning that it operates at set distances (orbits). He proposed that an object moving in a circular orbit has an angular momentum equal to its mass (m) times the velocity (v) times the radius of the orbit (r). As the electron ‘jumps’ orbits higher or lower, light is absorbed or emitted, in turn explaining the regular patterns of light (spectral series) emitted by hydrogen atoms. The light emited in this jump would later be known as photons.
Bohr’s theorisation of the electron’s orbit in a simple atomic structure drew from Max Plank, who had theorised in 1900 that light is emitted in discrete ‘quanta’ of energy. Einstein would confirm this in 1905 in his work on the photo-electric effect, in which he argued that light was quantised as photons, or small bundles of energy.
Taken together, the ‘Rutherford-Bohr’ model of the atom would fundamentally alter the trajectory of science, the gateway to an age of both quantum and nuclear physics. In subsequent years, scientists would confirm the existence of light as both wave and particle, and introduce notions of uncertainty operating at a fundamental structure of matter.
Bohr’s model of the hydrogen atom would be proven incorrect for more complex structures. Scientists would apply quantum theory to atoms with more complex structures, supplementing the circular orbits of hydrogen atoms with additional radial elliptical orbits. Knowledge of the behaviour of electrons would be supplemented by discoveries of additional elementary particles, including the proton (discovered by Rutherford in 1919/20) and the neutron (Chadwick, 1932).