The Chemistry of Light


Light is natural phenomenon that is vital for everyday activities. From a physics standpoint, light is super complex and interesting. I choses this topic because I was curious if light was equally interesting from a chemistry standpoint. Light is important because without light nothing would be able to survive.

Composition of ...The two main components of light are photons and energy.

Main Chemicals, Compounds, Components

Photons are created when elections are excited and rise and fall from different energy levels. Because of the new quantum theory, photons act as both a wave and a particle. From a physics standpoint, this has a lot of applications. From uncrackable codes to quantum supercomputers the possibilities are endless. Quantum mechanics in a simple sense is that things can be more than one thing at a time. To put it another way, let us look a computers. As Canadian Prime Minister Justin Trudeau explains that normal computers are a binary system, a “1” meaning power is going through a wire or “0” power is not going through a wire (on or off) but quantum states allow for the wire to be both on and off, allowing for more complex coding. Perhaps the most famous quantum thought experiment is Schrödinger’s cat, were a cat is placed inside a box with a poisonous gas that may or may not kill the cat. The cat is both dead AND alive until observation causes the quantum states to collapse into one leaving the cat dead OR alive.

The energy from light from our sun allows for life to exist here on earth. Plants use photosynthesis to turn carbon dioxide (6CO2) and water (6H2O) into sugar (C6H12O6 ) and oxygen (6O2). The plants use the sugar to grow which feed the animals who exhale carbon dioxide (CO2) for the plants to turn into sugar. The energy from the sun evaporates the water and causes rain to fall on the plants completing the cycle. All because of the energy of light. In more recent times, scientist have been able to artificially recreate this process to produce electricity in the form of photovoltaic, or solar, cells.

Chemistry's Role

Photon are created when electrons jump between energy levels. This can occur through both natural and artificial process. A common form of artificial light are street lights. They work by running electricity through a gas which excites the electrons and produces light. Fire is a natural example of light and give life to everything on earth (the sun). Fire creates light because there is enough energy in the fire to excite the electrons.

Background Research

The visible spectrum is the portion of the electromagnetic spectrum that human eyes can observe, ranging from about 400 nanometres (4.00x10-7 metres) to about 700 nanometres (7.00x10-7 metres). Speed of light in a vacuum is 299,792,458 m/s but 3.00x108 is commonly accepted and used.To put this into perspective the speed of sound at sea level at 20oC or 293.15 K is about 343 m/s.

Light can be made in several different ways. Fluorescent lamps creates lights by exciting different gaseous elements and different elements produce different colours. Chemiluminescence is light produced by a chemical reaction, like in glow sticks or naturally in glow worms.

Fluorescence is used in optical brighteners like washing powder by absorbing a small amount of UV light and re-emits blue light making clothes whiter than white. Fluorescence is also used in security markings on banknotes. Phosphorescence is similar to fluorescence but longer lasting and used in safety signs. Chemiluminescence, Fluorescence, and Phosphorescence are all used to make everyday things like luminous paint, hair gel, lipstick, and jewellery.

Theories about light have changed over the centuries but the Wave-Particle Duality theory is commonly accepted today. This theory states that light is both a wave and a particle and has applications in quantum physics. One example of the wave nature of light is that it is subject to the doppler shift. This shift allows scientist to show how stars are moving.

Light can be used to convert liquid monomers into solid plastic in a process called photopolymerisation. UV curing glue and dental glue that hardens under light are examples of photochemistry. Photodynamic therapy is used to fight cancer can by targeting the cancer cells


      1. General research about light
      1. Physics of light
      1. Background about light
      1. Making light
      2. What light is used for
      1. Properties of light
      1. About light
      1. Quantum mechanics
      1. Justin Trudeau on quantum computers
      1. photosynthesis
      1. How solar cells work

About the Author

Chet Kirby is a senior at Billings Senior High School and will be attending Montana State University studying Mechanical engineering. He has lettered several times in band and is currently working for NASA though their HUNCH program.