What simple experiment is possible to prove that the lunar surface is composed of dark rocks?

The white wall illuminated by the Sun appears brighter than the surface of the Moon, which is at about the same angular height above the horizon as the Sun.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.