An introduction to the formation of caves. Water can flow under the ground as well as above, in the form of underground rivers. Stalactites and stalagmites are some of the amazing formations which have been created by underground water.
Play the clip without sound and ask pupils to describe what they see. What questions would pupils ask the two people who appear in the clip? Compile a list of questions, then watch the clip again, this time with the soundtrack. Are any of the pupils' questions answered? Do they have any new questions? Children could go on to use a range of information sources, including the internet, to find answers to any of their outstanding questions. They could collect examples of rocks and stones for a classroom display and perhaps identify a local cave system on a map. Arrange a cave visit, if possible, to follow up on the classroom work. Children could also photograph examples of weathered or worn stonework in their neighbourhood (churches are a good source), comparing crumbling or flaky stone with better-preserved examples.