The activity I would choose would be on the planets.
As an intro to the topic the children would sit for circle time and look and listen to a picture book on the planets. Questions and discussion on the planets- focusing on unique features and some interesting facts using large visuals on IWB or printed pictures. E.g. Mars is known as the red planet etc.
Question: What is your favourite planet and why? (pair and group work or whole class discussion)
Activity: Using playdough make the planets of the solar system. Extension : show the mapping of the planets from the sun and on a laminated map ask the children to place their planets in the correct position.
Twinkl have lots of lovely resources and here is a cut and stick option that could be used if you didn’t have playdough- https://wordunited.com/free-resources/ordering-planets-cut-stick/
This could then be extended into group/ whole class projects whereby the groups/class create larger solar systems from large spherical balls (Mr. Price). These can be painted and decorated to look like each planet and then ordered and hung from the ceiling to create a class solar system.
They can recall facts and add fact file cards to each planet also. They can also create their own planet, using a template- they decide what it is made of/ what it looks like/ who lives their etc. Draw and discuss it with peers.