Sustainable materials: which metal?

Full details of the activity can be found in the new CIEC publication 'Sustainable Stories and Solutions for our Planet' which can be downloaded from  http://www.ciec.org.uk/resources/sustainability.html

Sustainable materials – which metal?

In this activity you will investigate how some metals rust when exposed to oxygen in the air and water. You will learn about some metals that do not change, corrode or rust easily and so have special uses, particularly in reducing gas emissions on highly polluted roads.

It would be a wonderful way to teach the ‘Properties and changes of materials’ strand of the science curriculum for Year 5, with a particular focus on how some changes result in the formation of new materials that is not usually reversible.

The Activity: 

·         Carry out a ‘rust hunt’ to observe how some metals change colour and become weaker (corrode) when they react to substances in the environment.

 ·         Investigate which metals rust by placing everyday metal objects in saucers of shallow water. Over several days, observe which objects start to show signs of rust and which do not. Steel wool pads can be used to test for signs of rusting.

·         Begin to form conclusions about which metals rust and what causes this to happen. You could use a magnet to identify metal items that contain iron or steel.

·         Think of your own ‘rusting’ enquiry questions, such as: can iron or steel rust when there is no water? Does salt speed up rusting? Can I prevent rusting? Plan and carry out your investigation; you can ask for extra ‘kit’ if you need it.

Results from rusting activity using a steel wool pad left for two days in different liquids.

·         Research how some metals, such as gold, silver, platinum and palladium, are unique because they do not react easily, change or corrode. These ‘precious metals’ are often used to make jewellery as well as catalysts which are fitted to car exhaust systems to turn harmful gases produced in the engine into safe gases. 

Links to the National Curriculum

Y5 Properties and changes of materials:

• explain that some changes result in the formation of new materials, and that this kind of change is not usually reversible, including changes associated with burning and the action of acid on bicarbonate of soda.

Working scientifically:

• planning different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
• recording data and results of increasing complexity using scientific diagrams and labels, classification keys, tables, scatter graphs, bar and line graphs 
• reporting and presenting findings from enquiries, including conclusions, causal relationships and explanations of and degree of trust in results, in oral and written forms such as displays and other presentations