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Make a sea potato

Activity make a sea potato hero

Have fun making a model of a sea potato and add it to your seabed in a box if you are making one.

Ages 5+

15+ minutes

Enjoy exploring seabed life by making a sea potato out of plasticine. Sea potatoes or common heart urchins are a type of sea urchin that burrow into the seabed. They are covered with spines and have lots of small legs underneath to move and feed.

Activity steps

Step 1

Make the overall shape of the sea potato by taking a 6 cm ball of modelling clay and shaping it like a heart.

Activity make a sea potato 1

Step 2

On what will be the bottom make an indent with your thumb to represent where the mouth would be. In nature, all sea urchins have a hole in their hard shells at the bottom for their mouth and one on top for their anus, with the soft organs in the middle. You could add a dimple on top for this last feature!

Activity make a sea potato 2

Step 3

Sea urchins have a five-fold symmetry which you can draw on the surface with a toothpick or modelling tool.

Activity make a sea potato 3

Step 4

Make the spines by rolling small sections of modelling clay and adding these to the surface of the overall shape.

Activity make a sea potato 4

Step 5

You can add tubular feet too using a different colour of modelling clay.

Activity make a sea potato 5

Step 6

Complete your sea potato by adding neon paint especially near and around the mouth area to show how the sea potato eats organic material in the sand.

Activity make a sea potato 6
Safety guidance
  • Make sure that children wash their hands thoroughly after using the modelling clay and paint.
  • Work on a non-stick surface.

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