Odd One Out

Maps of the solar system

Activity overview

15 mins
Ages 9 – 11

Science topics:


Put your class' observation skills to the test with these maps of the solar system from different time periods. This activity is great for promoting observation and discussion skills.

Run the activity

1. Show the three images above and ask everyone to come up with as many similarities and differences as they can. If they get stuck, prompt them to think about:

  • appearance
  • what they do
  • where they might be found

2. Then, everyone needs to decide which one is the odd one out and why. Encourage a reason for every answer and there is no wrong answer!

Background science

Astronomers such as Nicolaus Copernicus, Galileo Galilei, Johannes Kepler and Isaac Newton helped develop the heliocentric system (with the Sun at the centre) rather than the geocentric one (with the planets orbiting a stationary Earth). However, the first person to suggest a Sun-centred model was Aristarchus of Samos (c. 270 BC).  

Watch out for 

Some children may think that the images we show in the classroom, representing the Solar System, show it as it really is. Point out these are only models. 

For a detailed guide to children’s misconceptions and a guide to questions to assess prior knowledge look at these BEST resources.   

Take it further


These Ogden Trust research cards identify six key people and projects that made a contribution to our changing ideas about the Earth and space, and show how scientific ideas are developed.  

Children enjoy ‘recreating’ the movements in the Solar System on the playground with individual children representing a different planet by holding a ball (or an inflatable planet) and orbiting the Sun in an anticlockwise direction. This gives you an opportunity to point out that the planets do not orbit the Sun lined up as we sometimes see in diagrams. 

Why not follow this up by making a scale model of the Solar System using fruit? Full instructions can be found here. The Ogden Trust have two scaled models- one compares the relative sizes of the planets using playdough and the other compares the distances between them. Two models are needed to look at scale in the classroom because is really difficult to compare them both in one scaled model as NASA explains here.  

This great European Space Agency (ESA) activity has the children first guessing the distance of the planets from the Sun and then researching them. Children could research the size of each planet and the time it takes to orbit the Sun. What pattern can they see?


Linked Explorify activities- our recommendations: 

Start an interesting discussion by considering, Who should own space


This BBC video looks at Nicolaus Copernicus and this video looks at Galileo Galilei

Image credits:

Rosario Fiore via Flickr CC BY-ND 2.0;

Wikipedia Public Domain;

WikiImages via Pixabay CC0;