Filter Paper Planets

This activity is a fun introduction to chromatography while learning about the different planets in our solar system.

The idea is that children create each planet using filter paper while thinking about the size and colour of each one.

It’s impossible to get the size comparisons right as the difference, in reality, is so vast, but you can make some planets smaller than others.

You’ll need

Circular filter paper

Felt tip pens ( not permanent )

Pipette

Water

Tray

Diagram of the Solar System showing the planets in orbit around the Sun

Instructions

Choose a planet from the solar system and choose colours to use to make it.

Draw small circles of colour on the filter paper.

Carefully drip water onto each circle using a pipette.

Watch as the colours spread out. You should see some separation of each ink, showing its constituent colours.

Hang the filter papers up to dry and then cut to size.

Chromatography craft made to look like planets of the solar system. A child is dripping water from a pipette onto a small circle of filter paper made to look like a planet.

WHAT IS CHROMATOGRAPHY?

Chromatography is a scientific technique used to separate mixtures.

In this activity, the different colour inks in each felt tip travel at different speeds through the filter paper and so separate. Dark colour inks usually have more different colours than lighter colours.

This activity isn’t ideal for seeing the separation of the ink but looks good, and the colours blur together to look like a planet.

If you want to learn more about chromatography, set up an investigation using just a small dot of each colour felt tip at the bottom of a strip of filter paper and hang it so just the bottom sits in the water and watch as the colours separate as they move up the paper.