A practical I do with my year 9 group (but could be adapted for GCSE). We make a basic variable resistor by shading in an area on grid paper using graphite pencils. Then see how resistance is affected with length.\n\nI originally got the idea from a video clip I saw on YouTube, the link is attached here.\n\nYou will need to have digital multimeters to do this, that have a setting to measure resistance.\n\nNB: I'm a recently qualified teacher, so constructive comments on my resources and how they can be improved are really welcome! So please leave a comment if you used them! Thanks!