DEVISING A FAIR TEST WHEN DOING A PRACTICAL

This revision post should interest both Year 10 SiA1 and 11 PY as both classes are involved in doing practical investigations with direction; ie designing and implementing and writing up an experiment. Before carrying out the actual practical assessment the opportunity is being given for a practice run.

• in the case of year 10 the practice is to do with designing a Fair Test to investigate something to do with the swing of a pendulum. This will be followed up by another practice, this time called Hot Wheels

• in the case of year 11 the practice will be with a Metal Activity Series

This link gives a simplified step by step guide to designing a fair test

The main points are:

• Come up with an Hypothesis / Statement against which you are going to implement your Fair Test. If it is a statement this should be a statement of what you think is going to happen
• Identify the following variables: independent, dependent and control variables and make sure to list them all stating which type of variable they are
• The independent variable, which is plotted on the x axis, is the variable you have identified in your hypothesis as affecting the dependent variable, and is the ONE variable that you are going to change
• The dependent variable is the variable that is going to change as a result of you changing the independent variable, and is plotted on the y axis
• The control variables are all the other variables that could affect the fair test if you do not 'control' them, ensuring they are always the same
• Make sure that a full step step methodology is written down in your Fair Test stating how you are going to ensure that the test is fair, ie how you are going to measure the independent variable making sure that all the other control variables are taken into account and kept the same throughout the test. This methodology should be easy and simple enough for another group of students to pick up and carry out the same experiment you have just written and carried out!
• Make a table of observed results and a graph if appropriate
• Draw up your conclusions and evaluate whether the Fair Test you carried out was fair and either proved or disproved your original statement/hypothesis. Bear in mind that depending on your original statement you may or may not agree with the hypothesis; this is alright as long as you have carried out a fair test. If things did not work out as expected then your evaluation should include what you would change, or do differently, next time

Here is a link to a cool little simulation about the pendulum (particularly relevant to the10SiA1 class)