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However, in January this year, two separate scientific institutes electrovolts (eV). This is the amount of energy gained by the in the USA succeeded in stopping light for the first time.* Light electron or particle running through a voltage difference with a was sent through an optically activated supercooled sodium charge of one volt.° vapour. This made it possible to stop light very briefly before let- Nobel Prize—winner Niels Bohr designed a new model of the ting it continue to travel on.* atom in 1913. In this model, which is still the most widely known Colours are measured in waves from peak to peak, and the today, the electrons spin around the nucleus in stable orbits. He measuring parameter is the nanometre (nm). Red can be found between 670-760 nm, yellow, orange and pink between 560-630 nm, green at 490-560 nm, blue at 430-490 nm and violet between 380-430 nm (illustrations 1, 2). Violet light is more curved than red light because it has a shorter wavelength and it can be deflected more. There are as many different listings of nanometre citations for the wavelengths of the colours and other emissions of the Sun as there are scientific books dealing with this very issue! assumed that electrons can jump onto or off their orbits by absorbing or emit- ting a specific amount of energy: the quantum leap theory. The whole idea of an orbit depends on classical physics, whereas the idea of electrons corre- sponding to fixed amounts of energy levels comes from quantum theory. Bohr made his atom model by patch- ing together bits of classical theory and bits of quantum theory. Although his theory gave no insight into what makes atoms tick (and this model turned out to be wrong in almost every aspect), it helped him and the other scientists The mass of an atom's nucleus and electrons make up altogether only 0.000000000001%. Through the process of photosynthesis, the make progress because it provided a transi- Sun's energy is converted into chemical — tion to a genuine quantum theory for the energy by plants and __ bacteria. The remaining atom. Photosynthesis is one of the most significant But, because this model is so nice and reactions in nature and a prerequisite for 99.999999999999% simple—a "seductive picture of the atom as what is generally described as life. Oxygen Is free space. a miniature solar system" ’—it is still the for breathing is formed by the process of most widely used model, although it has out- hotosynthesis—a process that was 'invent- stayed its welcome. ed' about 350 x 10° years ago. The atmos- Illustration 5 shows the most modern here of the Earth at that time contained understanding of the atom. Here the atom is much more methane, and the current atmos- embedded in an electromagnetic field. A 3D heric oxygen content of 21 per cent was animation would beautifully demonstrate the developed by billions of photosynthetic vibrating atom and its electrons. The elec- activities using energy and sunlight. tron is simply something that moves outside Light has a paradoxical, dual nature; it is both wave and particle the nucleus and has a certain amount of energy and other proper- at the same time. However, it is impossible to measure wave and ties. It moves in mysterious ways. The electron 'likes' to stay article at the same time with the type of instruments and equip- near the nucleus. ment that are available at present; traditionally, the scientific The uncertainty principle postulated by Heisenberg says an methods used measure either one subject or the other. atom's exact position cannot be determined.* This is due to the The model of the atom was developed by Rutherford in 1911, wave characteristics of the particles. "As the electron is much and it has turned out to be the basis for our modern understanding lighter than the nucleus, its uncertainty is much higher and the of atomic structure and biophotons, even if this model is no longer area where it can be hit is much larger than that of the nucleus." regarded as correct by many quantum physicists. Electrons spin This creates the paradoxical possibility that the same atom may be in orbit around the atomic nucleus in a similar way to how plan- in different places at the same time. ets spin or rotate as they revolve around the Sun (illustration 3). ‘Wavelength 5 of sleus 2 - eee The protons of the nucleus are i= LTT LE LT a dT TG) positively charged and the elec- trons are negatively charged. {Ha} When a photon hits an electron, Energy ee ie er ee no be” 1 be eo oe ge ge it propels the electron onto the i. i n- s- 2o e e next outer and energetically wo or Raye - wm 0°! 1"? or * pO * Oo higher orbit or shell. The elec- tran will move on this shell for Heat-rays H Radiowaves as long as it can maintain the infrared new energy given to it by the photon. It then jumps back to its old shell, emitting energy = during this process in the form Ultraviolet Infrared of radiation measured in pho- tons (illustration 4). The ener- A gy of photons is measured in _ Illustration 2 The remaining 99.999999999999% is free space. Ilustration 2 NEXUS = 29 The mass of an atom's nucleus and electrons OCTOBER —- NOVEMBER 2001 www.nexusmagazine.com