This thermal conductivity demonstration can form the introduction to developing ideas about energy transfers between objects, and their specific heat capacity. Register for over 8,000 FREE teaching resources available from the National STEM Centre https://www.nationalstemcentre.org.uk/signup
Full details and teaching notes on how to introduce teaching energry transfer, and to a lesser extent specific heat capacity, may be found on the National STEM Centre Website
http://www.nationalstemcentre.org.uk/elibrary/resource/2087/thermal-conductivity
For detailed teaching resources on specific heat capacity: http://www.nationalstemcentre.org.uk/elibrary/resource/1468/episode-607-specific-heat-capacity