Physics is fun. Sure, it’s complex, full of formulas and jargon, but it’s important to know that without an understanding of quantum mechanics, we might still be at the mercy of the dark in the night. Quantum physics endeavors to explain the motion of things at the smallest of scales. No one has ever even seen an electron. Yet, experiments in quantum physics bear fruit. It explains how everyday objects function, objects that we usually take for granted, such as the technologies we use to light up our homes and communities.
For example, high intensity discharge (HID) lighting and light emitting diode (LED) lighting both produce light in the same way. Quantum physics tells us that a cloud of electrons orbit the nucleus of an atom. The further away the orbit from the nucleus, the more energy is contained in the electron cloud. If the cloud drops into an orbit closer to the atom’s nucleus, the extra energy is released. In the case of HID and LED lamps, the energy is released as a photon of light. However, the mechanism each lamp employs to release that photon is quite different.
HID lamps encase a gas of metal vapor in a tubular quartz capsule. When electricity is channeled through the capsule, free electrons from the power source collide with atoms in the vapor. The electrons in the gas are knocked into a lower orbit around their atoms and photons are released. The wavelength of the photon, which is what we perceive as color, is determined by the type of metal vapor and the amount of energy used. A ballast carefully regulates the voltage, which is why HID luminaires provide more light using less energy than either incandescent or halogen lamps.
LED lights also release photons due to the orbital transition of electrons. However, LED’s combine positive and negative semiconductor crystals into a diode, which is simply an electrical component that only allows current to flow in one direction. When energized by a power source, the electrons from the negative half of the diode are forced into the empty holes of the positive half, where they drop into orbit around the crystal’s atoms. As with an HID lamp, the size of the orbital drop determines the wavelength, or color, of the photon that’s released. Different semiconductor crystals offer different sized drops, which gives us the invisible infrared light on a television remote control through all the colors of the rainbow that we enjoy in various appliances and fixtures.
Whether you are aware of it or not, quantum physics is integral to our daily lives. It always has been. Yet, even without the advantages of our modern life, the sense of wonder that is nourished in the exploration of fundamental understanding is its own reward.