We have been learning about light sources and reflectors.
Light sources give off light which we can see in the dark.
Reflectors do not: Reflectors only work when a light shines on them.
Reflectors don't work in the dark without a light shining on them.
We tried this out today.
We used a dark box, put an object in it, guessed whether the object is a reflector or light source, shut the lid and had a look.
The others (including the mirror) were reflectors.
The moon reflects light from the sun; it is a reflector!