### Preparation

For the activity, move all the tables and chairs to the side of the classroom so that the students have plenty of room to act out a geometric shape. You could also use the gym or the playground. To make a constellation prepare containers for each pair of students, each containing glow-in-the-dark modelling clay, corrugated cardboard, 7 wooden skewers, 4 corks, a ruler, glue, scissors, and a waterproof marker. Cut the corks in half, ready for the students.

### Three-dimensional shapes

Organise the students into four groups of six students. Send each group to a different corner of the room. Each group chooses a geometrical shape to act out together. They hold hands and stand in a triangle, a square etc. Explain that they are not allowed to choose a circle.

Each group chooses one student to act as the coordinator. The other five students make the shape together. The coordinator in each group examines the shape from different sides. Does the shape look the same from all sides?

The coordinators draw the side views of their shapes on paper. Students discuss the drawings in their group then with the class and teacher. What do they notice? Does the shape change if they look at it from a different side? Why? Ask the students if they think this is also true for constellations.

You can ask students to explain why you told them not to choose a circle to test if they understand perspective.

Introduce students to the Orion constellation. Show students the picture of Orion in a bright sky and the drawing showing how we represent the constellation from the Earth in two dimensions.

Discuss with the class the position of stars in the constellation. Do they think the stars are on the same plane? Imagine that we could travel to another planet far, far away, would we make the same drawing? What does a constellation look like when seen from different sides?

Students make a constellation and demonstrate that what we see in the sky depends on our position.

### Make a constellation

Divide the group into pairs and give each pair a container. Students complete Task 1 on the worksheet. Explain that they must not press too hard on the cardboard when drawing the lines. Provide assistance in step 8 by cutting out the circle in the cardboard. While you cut the cardboard shapes, students start step 10 of the worksheet by placing the stars on the cardboard. When Task 1 is finished, students look through the eyehole at the three-dimensional Orion constellation and they draw the constellation as they see it looking through the eyehole.

See step 16 of Task 1 on the worksheet for tips for the students if they cannot see their constellation clearly.

### Not on one line

In Task 2 of the worksheet students compare their constellation with the picture of the constellation on a clear winter night sky. Do the students see Orion as shown in the drawing or the picture?

Encourage the students to look at their constellation from different sides and draw what they see. Ask them why the constellation looks different when seen from different sides. They should be able to explain that this is because the stars are not located on the same plane.

If they could travel through space to another planet very far away from the Earth, with a different perspective on the constellation, could we see the same patterns at night? Why?