5 Weeks to Go!

Know Your Practical Skills.

In a previous post I talked about the practicalities of making flash cards.  Have you had a go at making any yet?  Over the past couple of years there has been a greater emphasis on students learningformulae, and flash cards are ideal tools for helping with this.  So on one side of the card write the formula needed – for example, what is the formula that links distance, speed and time? – and on the reverse side write down the answer (speed = distance divided by time  – as if you didn’t know!).

The cards can also be useful in learning your basic practical-related skills.  Do you know the names of all the commonly used practical equipment?  You need to be able to distinguish between your conical flask, beaker, measuring cylinder, etc.   And do you know your Physics equipment?  What do you use to measure current and voltage?  Check your spelling – an instrument used for measuring is a meter(eg. thermometer), whereas a unit of length is a metre(eg. millimetre).

How confident are you with experimental design?  In any experiment you will have three types of variables. The independent variableis what you are changing.  For example, in an experiment to measure the rate of reaction between magnesium and hydrochloric acid, your independent variable would be the acid concentration – you might carry out the experiment using five different concentrations.

In this experiment, your dependent variable (what you are recording) would be the change in mass of the magnesium, or the time taken for the magnesium to disappear.   Finally, you have control variables– you need to keep these the same throughout the experiment.  In our example you would need to keep constant the temperature, the volume of acid, the mass of the magnesium at the start – and I’m sure you can think of others.

Having carried out the experiment do you know how to present the data in a table?   Do you know how to draw the graph?  On which axis should you put the independent variable? (normally it’s the x-axis – I’m assuming here that you know your x-axis from your y-axis!).

Analysis of an experimental design, or analysis of recorded data could come up anywhere in your exam paper, so make sure you are prepared – revise your practical-related skills!