1. Nature of Light
for all light sources (natural and artificial) atoms in the materials must absorb some form of energy causing electrons to become “energized”
the electrons then immediately release this energy in the form of light
light is a form of energy that travels as invisible electromagnetic waves at 300,000 km/s through empty space

2. Properties of Light
a light ray travels in a straight line as long as its travelling through the same substance
light can completely go through or be partially or totally reflected or absorbed when passing through a material
transparent - when a material allows objects to be clearly seen through it (e.g. glass)
translucent- when a material does not allow an object to be clearly seen through it (e.g. waxed paper)
opaque– when a material does not allow objects behind it to been seen at all (e.g. cardboard)

3. Nature of Light
the electromagnetic spectrum is a diagram that shows the range of electromagnetic waves in order of wavelength from longest to shortest
visible light only makes up a small portion of the spectrum
colours are just different wavelengths of light (i.e. ROYGBIV)