Shadow is formed when an object blocks the source of light.Here the transparent objects allow light to pass through it so there is no shadow formed.
Shadow is only formed when light can not pass through the object.In transparent object light passes through thoroughly.Thus,opaque objects oly form shadow.
mordenisation has disabled man.
transparent object allows all the light to pass thru them. only objects [opaque objects] that block light can form shadows.
because light passes through it without any deflection.In opaque objects light is not allowed to pass through it so it forms a shadow