Also needed is an idea of how light is either emitted from a luminous source such as the Sun, or else diffusely reflected from a non-luminous object such as the Moon. Considerable evidence exists that young children do not often use this scientific model to explain how they see things. One study found at least one third of the children surveyed thought some kind of 'light' travelled from the eye to the visible object. Only one student out of 21 correctly described light reflecting off an object and travelling to the eye. It is not just children who entertain misconceptions.
Several studies report survey results with teacher trainees, university students and teachers.
Half the students taking a university geology course in the USA could not explain the cause of seasons. Several related concepts involving the nature of light, vision, reflection, gravity and the relative sizes, distances and motions of a spherical Earth, Moon and Sun in space are all required to synthesise a satisfactory explanation for phenomena such as Moon phases or seasons. Thus, it is not surprising that most children and many adults are unable to explain the phenomena correctly. The importance of adult misconceptions increases significantly when they become teachers. It is important to give clear reasons to children for why scientific explanations are better than common misconceptions.