Resources: A beaker (eg 250 ml and 100 ml), a thermometer, a kettle to heat water, a piece of cardboard, scissors, a stopwatch and insulating material (e.g newspaper, corrugated cardboard, bubble wrap or rubber bands).
Handout: Plan the practical to investigate how changing the insulation material affects the cooling rate of a beaker. Write the method for the investigation and record the variables. Record the results and plot a graph to show the cooling curves. Analyse results and discuss errors.
Ask the students: What material do you predict will be the most effective insulator and why?
Use the handout to introduce each aspect of the experiment. The students are to consider the hypothesis and what the question is asking them to do. They should make a prediction of the outcomes and plan in an organised and systematic order. Furthermore, they should consider hazards and make a full risk assessment as well as consider the sources of significant error to the validity of the data that they will collect. They should understand how to process that data and make mathematical calculations to find for the variables. They should conduct a thorough analysis of the data that they collect.
Career Film: This is Chris Cunliffe. Chris works as a Research Technologist for National Nuclear Laboratory.
Expert Film: This is Dr. Tim Gregory, who works as a Chemical Analyst for National Nuclear Laboratory. Tim talks about insulating material.
Mr Rees shows you how to find out the relationship between insulation thickness and rate of heat loss.
Challenge Task: Ask the students the following questions: What are the methods of thermal energy transfer in this experiment? How are we reducing them? How else could we reduce the rate of cooling? How does a thermos vacuum flask keep liquids and food hot for a long time?
Use the summative quiz to assess students' learning. Discuss the results of the practical. Which material was the best thermal insulator? Can you explain why it was the best? What was the shape of the graph? What does this tell us about how an object cools? What did the results show for changing the layers of bubble wrap? Can you explain this?