Trundle, Atwood and Christopher (2002)

This US study looked at the conceptual misunderstanding about the phases of the Moon held by pre-service, primary-school teachers (early stages of teacher training), before and after instruction. Two groups of teachers were analysed, one group receiving no instruction and another receiving training about Moon phases based on a Physics by Inquiry programme.

Learners’ ideas

  • Most teachers did not understand that half of the Moon always is illuminated by the Sun.
  • A significant number of teachers thought that the Earth’s shadow causes the phases of the Moon.
  • A small number of participants incorrectly linked Earth’s rotation to the cause of Moon phases.
  • Some thought that the Moon’s phases are caused by a planet’s (other than the Earth) shadow on the moon.
  • Some teachers did not recognise that the Moon orbits the Earth.
  • Other misconceptions included:
    • Moon phases are caused by the Earth's tilt.
    • Moon phases are caused by the sun’s orbit of Earth and Moon.
    • Moon phases are caused by a varying amount of light on the moon from the Sun.
    • Moon phases are caused by the varying distance between the Sun and Moon.

Evidence-based suggestions

The teachers recommend the use of the instructional sequence in Physics by Inquiry (McDermott, 1996) as a logical starting point for persons interested in providing instruction on Moon phases.

Further suggestions

  • Two-dimensional drawings in texts of the Sun, Moon, and Earth may well reinforce the incorrect notion of these three objects being in the same plane.
  • Diagrams showing lit portions of the Moon during the phases often give the false impression that less than half is lit at any time and so should be used with caution.

Study Structure


This study looked at the conceptual understandings held by pre-service, primary-school teachers about moon phases, before and after instruction. The research questions were:

  1. Before instruction, what are the types of conceptual understandings held by elementary pre-service teachers about the cause of moon phases?
  2. How do elementary pre-service teachers’ conceptual understandings of moon phases differ after completion of the instruction on this topic?
  3. On the cause of moon phases, how do the conceptual understandings of elementary pre-service teachers who completed the instruction compare with those who did not?
  4. Does using a three-dimensional model or making a two-dimensional drawing during pre-instruction interviews have instructional value?

Evidence collection

Evidence was collected via a qualitative protocol developed for the study. This included a set of standard interview questions with follow-up questions by the interviewer. Interviews were recorded and analysed. The analysis sought to identify common misconceptions.

Details of the sample

The sample consisted of 98 pre-service primary school teachers training at a major Southeast American research university. 91% of the 78 participants were females; 91% were White, and the others were African-American (6.4%), Asian-American (1.3%), and Hispanic-American (1.3%).

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