Light, in its simplest form, is electromagnetic radiation. That might sound scary, but it’s actually quite normal. The only “radiation” that should worry you as a person is ionizing radiation, which is very high-energy light that can cause direct damage to your cells. Ionizing radiation is not common in your day-to-day life, so it shouldn’t be a direct concern to you.
The light we see as humans is only a small fraction of the entire light spectrum. Our eyes are only capable of seeing a relatively narrow band of light known as the visible spectrum. “White” light is actually a composite of multiple different colors of light combined, and can be separated out into its constituent lights with a prism.
Author’s Note: Other species of animals can see different parts of the light spectrum; predatory reptiles can typically see in the infrared portion of the spectrum, and pollinating insects often see in the ultraviolet portion of the spectrum.
Light can be measured in multiple different ways, depending on its application, but we’re going to start simple and look at Amplitude and Wavelength, two very important components of defining light:
- Wavelength refers to the physical length of the light. Yes, light has a certain “size.” Longer wavelengths are “redder” and contain less energy overall, while shorter wavelengths are “blue-er” and contain higher energy overall.
- Amplitude refers to the intensity of the light. Think of it as the “volume” on a radio or music player. Amplitude does not change the color of light, only how strong that given light is.
Author’s Note: There are other important components of light, including polarization, propagation direction, and speed in a given medium, but these components are generally not important to your average grower.