# What is the significance of wavelength when referring to light (in layman's terms)?

Without any equations or complex terminology, I simply want to understand in complete layman's terms what the significance of a single photon's wavelength is. People say that microwave radiation's wavelength is as large as a baseball, and that a radio wave's wavelength is as large as the statue of liberty, but what does that even mean?

The photon is not literally going up and down constantly, photon's go on an almost straight path always, in a vacuum at least. What is the significance of saying that the wavelength is higher or lower, other than that a higher wavelength is less energy and lower is more energy? What are the legitimate physical characteristics measured that distinguishes all of these different sections of wavelengths apart from one another?

• Key point: when we talk about the wave in electromagnetics we are not talking about the position of the photon oscillating (the photon doesn't "go up and down") We are talking about an oscillating electrical field. The peaks and troughs of the wave are where the electrical field minima and maxima occur. The wavelength is the distance between two locations where the of the field reaches its maximum value. Aug 22, 2015 at 15:33
• it seems so fitting when The Photon conveys information... about... light May 20, 2016 at 17:47
• In layman terms, light is composed of photons, a photon is not light. similar to "A building can be made out of bricks. Bricks are not buildings". see en.wikipedia.org/wiki/… May 20, 2016 at 18:01

Wavelength is used as a convenience. It's much easier to imagine a photon with a 500 nm wavelength than to comprehend a photon oscillating 600 trillion times per second. But in reality that's all it is is a photon moving at the speed of light and oscillating 600 trillion times per second as it goes along. The photon completes one cycle every 500 nm. Many on this site do not agree with The idea of single photons so I'm sure this will be down voted but it does agree with experiment. The idea of a wave can only be explained with billions of coherent photons. Looking at photons this way it is easier to see why higher frequency photons have more energy.

When these terms are used, light is been pictured as an electro-magnetic wave.

Thinking of the microwave example, inside what you would have is like a sea where light is equivalent to the undulations. So in this picture, the wave-length is the distance between two consecutive wave peaks. Larger wave-length implies more separation between these peaks.

Also the relation between wave-length and energy is also very similar to the sea picture. Large wavelength implies the "push" you get from several waves takes is more spaced, hence you receive less total energy per time interval.

On the contrary when the wave-length is shorter, you receive the "pushes" more frequently, i.e. they are less distanced from each other, and coming one after the other more rapidly, and the transfer of energy is higher.

Finally, to clarify the classical view of light: it is an electro-magnetic wave, that is a self-sustained oscillation in space an time of electrical and magnetic fields, each of them generating the other and propagating freely through both media and vacuum.