Saturated Solutions

• Consolidate what learners have learnt in their own experiments by showing these two videos:
• Show VIDEO CLIP 5: How to make your own sugar crystals (3:15 min.).
• Show VIDEO CLIP 6: How to make your own salt crystals (3:09 min.). 
• Tell learners that we also find crystals in nature. These crystals are large and they are called stalactites and stalagmites.  Can the learners guess where we find such crystals?

Answer:  In limestone caves, such as the Cango Caves in Oudtshoorn.

• Explain to the learners that the stalactites hang down and the stalagmites grow upwards from the floor of the cave.
• Caves are formed when the water slowly dissolves the limestone underground. The dissolved limestone can crystallise when water evaporates.  This is a very slow process.  Water drops from the ceiling of the cave and then it falls on the floor.  As the water evaporates over time, a stalagmite will ‘grow’ in that spot. 
• Show VIDEO CLIP 7: The Cango Caves in South Africa (1:31 min.).