Sometimes reading a description of a geological process in a textbook just isn’t enough. Folding and faulting is one such case where it can be difficult to understand how movements in the plates that make up the surface of the earth can fold previously flat beds of rock into hills and mountains.

At the Lickey Hills Geology Open Day last Sunday, geologists had a “sandbox” (kindly loaned by the University of Birmingham School of Earth Sciences) ready to show visitors folding and faulting in action. The photos below show how it happened.

The box is loaded with layers of different coloured damp sand and a willing volunteer turns the screw thread which compresses the sand from the end.

As the sand layers are subjected to more and more pressure from the side, they begin to slip diagonally over each other (faulting) and bend (folding)

Here we can see folding in rocks that are 488 million years old, in a quarry on the Lickey Hills, outside Birmingham