1.1 Characteristic of the Big Idea

According to the concept of Harlen´s Big Ideas in Science, this particular Scientific Idea covers following understanding of the particular natural phenomena: “Our Sun and eight planets and other smaller objects orbiting it comprise the solar system. Day and night and the seasons are explained by the orientation and rotation of the Earth as it moves round the Sun. The solar system is part of a galaxy of stars, gas and dust, one of many billions in the Universe, enormous distances apart. Many stars appear to have planets.” (Harlen, 2015).

1.2 Suggested development of the Idea at primary education level (7–11 years old pupils)

Big ideas are at primary age in intense development. To support the further development of the Idea, pupils at primary age should be exposed to the following level of the Idea: “The Earth moves round the Sun taking about a year for one orbit. The Moon orbits the Earth taking about four weeks to complete an orbit. The Sun, at the centre of the solar system, is the only object in the solar system that is a source of visible light. The Moon reflects light from the Sun and as it moves round the Earth, only those parts illuminated by the Sun are seen. The Earth rotates about an axis lying north to south and this motion makes it appear that the Sun, Moon and stars are moving round the Earth. This rotation causes day and night as parts of the Earth’s surface turn to face towards or away from the Sun. It takes a year for the Earth to pass round the Sun. The Earth’s axis is tilted relative to the plane of its orbit round the Sun so that the length of day varies with position on the Earth’s surface and time of the year, giving rise to the seasons.” (Harlen, 2015)