This study looked at whether the illustrations typically used in textbooks assisted in understanding the phases of the Moon and whether trainee teachers could produce their own accurate explanations using diagrams. This process identified a range of misconceptions held by the student teachers and the limitations of the illustrations. The research was carried out by a university researcher in Spain.

Learners’ ideas

• Students do not have a clear idea of the Sun/Earth/Moon model - they had difficulties expressing themselves in diagrams.
• Incorrect interpretations of relative movements e.g. the Sun revolving around the Earth.
• Students frequently confuse the positions of the full Moon and the new Moon, because they consider them to be fixed, independent of the relative position of the sun.
• Students attempt to explain the new moon as an eclipse, through the projection of the earth's shadow.
• Some students think that when the Moon is in its fourth crescent, only a quarter of the Moon can be seen.
• Some students think that the Moon can only be seen at night.

Evidence-based suggestions

• Images used in textbooks are usually not, by themselves, sufficiently explanatory.
• Care should be taken when analysing astronomical images in books.
• Issues with common moon-phase diagrams include:
  • The Sun's position is not indicated
  • In the Sun/Earth/Moon model representation, the three bodies are aligned in such a way that the position of the full moon is the same as that which gives rise to an eclipse of the Moon.
  • In the Sun/Earth/Moon model representation, the phases are drawn in such a way that they are seen from the Earth. However, it is not explained to the pupil that he/she is observing the drawing that must be imagined mentally from Earth, in order to understand it.
  • The relation between the duration of the phases of the Moon and the weeks of the month is not explained
  • The text that accompanies the figure is a mere description of the phenomenon not an explanation and in some textbooks, both descriptive and explanatory texts are missing
  • Some mnemonic rules used to link shape and phase added confusion rather than clarifying.

Study Structure

Aims

The study had two parts:

1. Analysis of the images concerning the phases of the moon that appear in Primary and Secondary textbooks.
2. Analysis of the conceptions and graphical representations of 78 students in the third year of university (teacher training) within the subject ‘Environmental Knowledge and its teaching and learning’.

Evidence collection

The researchers analysed a range of astronomical images found in textbooks. They also analysed conceptions and graphical representations of university students in their third year of university via a questionnaire, along with their ability to use textbook diagrams and their own diagrams in their explanations. A qualitative analysis of student answers was completed.

Details of the sample

The research sample consisted of 78 3rd-year university students on teacher training courses.