Professor Brian Cox explains the concept of entropy and the arrow of time.
He uses a pile of sand to explain how entropy is the measure of how many ways in which something can be rearranged.
He then explains that the world always tends towards disorder, from order, hence time only goes in one direction.
Teacher Notes
This clip is useful for students of Physics or Chemistry.
It can help explain why travelling backwards in time is not possible.
It is also useful at introducing some interesting and powerful concepts that can help build understanding in many other areas of the curriculum.
Curriculum Notes
This clip will be relevant for teaching Physics and Chemistry. This topic appears in OCR, Edexcel, AQA, WJEC KS3 and GCSE in England and Wales, CCEA GCSE in Northern Ireland and SQA National 4 and 5 and Higher in Scotland.