I use this exercise when teaching solids to my kids and it makes a great activity for groups of 4-6 students. You need plasticine or modelling clay, matchsticks or toothpicks ....and big tables or a working area.

I introduce the basic concept of cubes and pyramids, and show how to make balls of clay about 1cm in diameter, and how to connect them together using the sticks. Then I assign 4 tasks:

• make a cube
• make a pyramid
• make a house (combine cube and pyramid.)
• make a tower using multiple cubes and one pyramid to crown the top.

The first group to make a tower from at least 4 cubes wins a prize. The real challenge here is for the students to work together and to become junior engineers by creating a stronger structure than their classmates. Everyone has a great time and the session can be very amusing!