distance between consecutive peaks (or troughs) of a wave
measured in meters; light wavelengths typically in nanometers (nm)
determines color in the visible spectrum: ~380 nm (violet) to ~700 nm (red)
determines pitch in sound: longer wavelength = lower frequency = deeper tone
related to frequency by: wavelength = speed / frequency
electromagnetic spectrum spans radio waves (km) to gamma rays (pm)
de Broglie wavelength assigns a wavelength to particles with momentum
diffraction and interference effects depend on the ratio of wavelength to obstacle size
antenna length scales with the wavelength of the signal it transmits or receives