This study examined children’s concepts of the shape and size of the Earth, Moon and Sun through longitudinal research based on one-to-one interviews and, for students aged 13-18, a preliminary written questionnaire. Students’ ideas about the relative and absolute sizes were probed using interviews, written questionnaires, drawings and photos of play-dough models. The research also checked for any apparent cultural differences in students’ ideas. The research was carried out by university researchers in the UK based on data collected in China and New Zealand.

This paper serves as a good resource for understanding the simple models of the Earth, Moon and Sun students construct before their formal education and how these change over time. Insights into typical beliefs are clearly shown and discussed. The paper also shows the importance of constructing ways for students to express their understanding beyond simple testing.

Learners’ ideas

• Children may know that the Moon changes shape but may believe it to be disc-shaped.
• Child modelled the Earth as a slightly flattened egg shape, the Sun as a disc with ray-like indentations and the Moon as a disc and a banana shape.
• The Earth is disc-shaped: people live on the flat top surface (ground).
• The Earth is shaped like a ball cut in half. The ground and sky are inside the Earth.

Suggestions

• Children should be introduced to a range of comparative sizes and shapes for the Earth, Sun and Moon from an early age.
• Lessons on the shape and size of the Earth, Sun and Moon should include activities which provide the ‘direct experience with phenomena’. These should include observational astronomy such as activities to measure the size of the Earth and Moon.
• Before they can gain a conception of the size and shape of the planets, children must be able to see objects in three dimensions from multiple perspectives, and ultimately from the perspective of observers in space (decentration).
• Children should be introduced to the concepts of scale and relative size to enable them to construct scale models.
• Teachers should also become familiar with the wealth of children’s literature on the shape and structure of the Earth–Moon–Sun System and planets of the Solar System. They should take care to use post-Voyager materials which show photos of the planets in great detail.

Study Structure

Aims

The study examines students’ understanding of the shapes sizes and nature of the Earth, Moon and Sun and how these developed over time.

Two hypotheses were tested quantitively using the data collected in the study:

• H1: Concepts of Earth's shape and size are embedded in a ‘super-concept’ or ‘Earth notion’ encompassing concepts of physical shape, ‘ground’ and ‘sky’, the habitation of Earth, and identity with Earth; which mediates concepts of the shape and size of the Moon and Sun.
• H2: The development of concepts of shape and size of the Earth, Sun and Moon is similar in cultures where teachers hold a scientific worldview.

Evidence collection

For children aged 3-12, the interviews were based on an extensive interview Guide. For students aged 13-18, an extensive written questionnaire inviting written and drawn responses was combined with interviews to clarify ideas.

The data was initially analysed, categorised and coded by the researcher using a modified version of the Concept Categorisation Scheme developed by the authors. The written and verbal data from China was translated and transcribed by the researcher’s interpreter who was familiar with the research methodology. The data was then analysed, categorised and coded.

Details of the sample

The research sample consisted of 248 participants in all, aged 3-18 years. This is broken down as:

• 68 kindergarten, pre-school and junior school pupils (34 from New Zealand including 18 males and 16 females; and 34 from China including 19 males and 15 females)
• 68 primary school pupils (34 from New Zealand including 16 males and 18 females; and 34 from China including 15 males and 19 females)
• 56 middle school students (32 from New Zealand including 13 males and 19 females; and 24 from China including 14 males and 10 females)
• 56 high school students (29 from New Zealand including 11 males and 18 females; and 27 from China including 18 males and 9 females).