Taking a Wall for a Walk

We sent a group of Yr9 students to Grizedale Forest in Cumbria to track down an early sculpture by Andy Goldsworthy called Taking a wall for a walk. Eventually they find it.  Is a wall a sculpture, does it matter that time has changed the work and should the artist make it all themselves?   You can use this film to start a debate in your classroom about what is sculpture and should it be allowed to change over time.