Light is now understood to have the properties of both waves and
     particles. The best way I can picture this is in the picture "Light"
     which I drew. Wavelength is the distance between wave crests. Try to
     picture each wave crest as having 1 photon in it. The photons
     themselves, however, are not following the wave pattern; somehow they
     are traveling straight right. The new word for light is "wavicle".
     (Cute, please believe me, I didn't invent the word). In the picture,
     the grey vertical line on the right is a wall which the photons are
     striking.

     Try to imagine if the wave crests were closer together. This would be
     called a shorter wavelength, and would correspond to a higher
     frequency; more photons would hit the wall per second. Since light
     always travels at the same velocity, an increase in frequency is
     accompanied by a decrease in wavelength. Gamma rays have the shortest
     wavelength, while radio waves have the longest wavelength. This
     relationship is called inverse variation.