Princess and the PEA STEM Challenge

In the story of The Princess and the Pea, the princess can't sleep because she can feel a pea through many layers of mattresses. We used the story to inspire first the building of a wooden bed and then the addition of mattress materials to see which cushioned our pea ( a marble ) most effectively. This Princess and the Pea STEM activity is great for kids of all ages and for working in a team or alone.

If you like this activity, we have lots more fun Fairy Tale STEM Challenges to try, too.

It's also a great STEM Challenge for World Book Day.

Princess and the Pea STEM Challenge

The challenge is first to build a bed frame and then test different mattress materials.

If you don't want to build a bed frame, you can also test mattress materials on a flat surface.

This printable planning and testing booklet might also be helpful.

The bed was built by my 9-year-old using materials from TTS. He used wooden dowels, square lengths of wood, triangles and a glue gun ( with help from me ).

Materials

A bed - if you don't want to make your own, this could be as simple as a thick piece of card or a small doll bed

A marble

Mattress materials such as sponges, bubble wrap, felt, etc

How to make a bed for the Princess and the Pea

Look at your materials and think about which would make the best mattress. Remember, the challenge is not to be able to feel the "pea" through the mattress.

Construct your mattress.

Press down, can you feel the "pea"?

Ask a friend to feel the mattress without telling them there is a hidden marble. Can they tell there is something there?

Princess and the Pea - Extension tasks

Investigate to find the thinnest mattress you can make and not feel the pea?

Find out whether the object in the bed affects how thick your mattress needs to be. Try using a coin or a dice.

Great for Key Stage 1 Science - Everyday Materials

Everyday Materials - Identify and compare the suitability of a variety of everyday materials

Working Scientifically

Last Updated on June 6, 2025 by Emma Vanstone