# 4 — Acting out and making models

The students may find it difficult to visualise the movement of both the Earth and Moon so it is important to give them an opportunity to physically recreate the motion and embed their new learning. In this sequence they will engage in activities that allow them to act out the movement of the Earth and the Moon in relation to the Sun and construct models that demonstrate their new understandings.

## Activity 1: Acting out

As a whole class, discuss the poster that was jointly constructed in the previous learning sequence. Discuss and exemplify the size of each celestial object using everyday equipment such as balls, marbles and peas to assist. Alternatively, images could be displayed from The size of the Sun in comparison on the Did you Know? website (only the first comparison is necessary).

Organise the students into groups of three to physically model the movement of the Earth around the Sun, while spinning on its axis, and the Moon orbiting the Earth. Remind them that one rotation of the Earth on its axis takes 24 hours and a complete orbit of the Earth around the Sun takes one year. Remind them that it takes 27 days for the Moon to orbit the Earth. The students should adopt body shapes and positions to imitate the differences in sizes of these celestial bodies, and move at different speeds.

Observe the students’ representations and through discussion and questioning determine whether they have grasped the concepts. Revisit the concepts, if necessary, to correct misconceptions.

## Activity 2: Making models

This activity will help the students to develop an understanding of the location of each of the objects in relation to each other and will introduce other objects in our solar system.

Have the students construct scale models of the planets in the solar system, using objects such as foam balls, peppercorns, peas and plasticine. They can then place these models at the approximate distances apart according to scale. There are a variety of website calculators that will enable you to enter a reduced diameter for the Sun and these will calculate the distances from the Sun to the Earth and provide the scaled diameters for each planet in the solar system. Two such calculators are:

Use the school oval or playground to step out the distances, as this may give the students a clearer understanding of the immense distance between each object (it will also allow you to create larger models).