light
all metals can reflect the light
there are wave lengths that range from 390 to 700 nanometers
you got light sources like
electric discharge,lamps,
nuclear and high-energy
paricles, celestail and
atmospheric and more
materials that let light throught are air, water and glass but ones that dont let any light are wood, bricks chalk boreds and walls.
shawdows are made when
you block the light rays that
are traviling in a straight line.
the position your in is the how
you make a shape or the size
of it.
foil, black paper, mirrors,
plastic sandwiches,metal,
waxed paper and smooth
and shiny objects and a
lot more can reflect light.