1. LIGHT WAVES
Like sound waves and waves in water, light
can travel through matter. Light waves can
travel through space that contains almost no
matter.

2. Electromagnetic waves
• Electromagnetic waves are waves that can travel through
matter and through empty space.
• In empty space, light travels at about 300,000 km/s. Light
travels fastest through empty space and slowest through
solids.

3. Wavelength of light
• Wavelength of light are usually measured in a unit called
the nanometer (nm). One nanometer is very small.
• 1 m= 1,000,000,000 nm