An investigation into friction on the ski slopes. Does waxing skis make them faster? An 8-year-old girl tests three different types of skis, unwaxed, waxed, and self-waxing. She tests each type three times to ensure reliable results. She considers variables and only changes one at a time, making it a fair test.

First broadcast:
5 March 2008

This clip can be used when starting investigations into how to create less friction between objects. It could be used to emphasise the need for fair testing to give more reliable results, and of changing one variable at a time; this could be a focus of the pupils' work in designing their own tests. The clip could also be used to illustrate how using results can help to draw conclusions and suggest improvements for further tests.