How many stars can you see in the night sky? by DrSimmo is a great post. As an ex-project officer for Scientists in Schools, it’s also wonderful to still be hearing about successful partnerships like his!

It reminded me of a fun and effective science and technology activity that can be done to demonstrate that light is a form of pollution too. This idea was first given to me by Rob Hollow, CSIRO ATNF Education Officer at a CONASTA a few years ago.

You will need a black piece of card, a pencil, a ruler, glue, a compass (the pointy kind, not the magnetic kind), and a torch. If you’re feeling really finicky, you might like a book or map of some constellations (western, Indigenous Australian, greek…).

Use the pencil and a ruler to mark out the edges of a cube on the black card. Each face of the cube will be about 5 cm square. Draw flaps on the edges of some of the faces so that you can glue the cube together (it’s a fun – for a given definition of fun! – mathematics and technology challenge for kids to work out where they should put the flaps).

Before gluing, draw a circle on one of the faces of the cube and cut it out. If you’re using a glue stick, usually the lid of the glue stick is a good size (about an 2.5 – 3 cm in diameter).

Glue the cube together. Using a pencil, mark some constellations onto each of the five uncut faces of the cube. Have between 50 and 100 dots on the cube altogether. Count them!

Use the compass veeeerrrrrrrry carefully to poke holes where you have marked your constellations.

Turn the torch on, and the lights off.

Shine the torch up through the cube and watch the stars appear on the walls and ceiling!

By varying the amount of light in the room, students can count how many stars they can see. They will see less stars in a lit room than they do in a shadowy or darkened room. This is the effect of light pollution, and we can see the difference between the light pollution in the city and the country, just as Dr. Simmo says.