Light is a form of energy that travels in waves, much like ripples spreading across a pond. But unlike water waves, light doesn't need a medium to travel through. It can zip through the vacuum of space. This is because light is a type of electromagnetic radiation, a stream of energy that has both electric and magnetic fields.

This electromagnetic radiation exists across a huge range of types, from long, low-energy radio waves to short, high-energy gamma rays. This entire range is called the electromagnetic spectrum. The light we can see with our eyes is just a tiny sliver of this vast spectrum.

What we perceive as different colors are actually just different wavelengths of visible light. When you see a rainbow, you're seeing white sunlight split into its component colors. Each color corresponds to a specific wavelength.

The colors of the visible spectrum always appear in the same order, from the longest wavelength to the shortest: red, orange, yellow, green, blue, indigo, and violet. A simple way to remember this is the acronym ROYGBIV.

A light wave's wavelength is directly related to its frequency and energy. Frequency is the number of waves that pass a point in a given amount of time.

Think of it like jumping rope. If you make long, slow waves with the rope, that's like a long wavelength. You don't use much energy. If you shake the rope quickly to make many small waves, that's a short wavelength, and it takes a lot more energy.

This means that violet light, with its short wavelength, is more energetic than red light, which has a long wavelength. Beyond the visible spectrum, ultraviolet (UV) light is even more energetic, while infrared (IR) light is less energetic.