Applied Science AQA/Resistivity Portfolio

Syllabus Content

Materials scientists need to be able to recommend appropriate materials for electrical components in a huge range of products.

In completing investigations, learners will develop their knowledge and understanding of the following concepts:

•    the meaning of resistivity

•    how the resistance of an electrical component relates to the resistivity of the material it is made from

•    importance of knowing the resistivity of a material

•    uses of materials with both high and low values of resistivity, including, for example, new semiconductors used in electronic circuits

•    use of standard procedure to measure the resistivity of a piece of wire

•    accuracy and reliability of data, recorded with appropriate precision

•    methods used in industry

•    recording appropriate measurements:

•    calculate a value for the wire’s resistivity

•    calculate the theoretical percentage error

•    calculated value compared with researched value for resistivity of the wire’s material

• reasons for differences between theoretical and calculated values

•    evaluation of methodology.

The Brief

criteria for resistivity portfolio

Advice

DON'T just copy and paste anything! You can't get any marks for something someone else wrote.

Use the official glossary to clarify the meanings of the words accurate and precise.

Checklist - before you hand in:

Have you:

Pass

• Given a definition of resistivity
• Explained the differences in behaviour between materials with a high and a low resistivity, using examples
• Carried out the experiment and found a value for resistivity - with units (probably from a graph gradient)
• Written a full risk assessment

Merit

• Chosen examples of materials with high and low resistivities and explained why these materials are used for particular purposes in industry
• Compared the value from your resistivity experiment with an official value - evaluated and explained why yours is different.

Distinction

• Written about industrial methods for finding resistivity- and explained how they are both more accurate and more precise than your classroom method - e.g. the conditions in which they are carried out