Those pesky independent, dependent and control variables? Are they continuous or categoric? Which are the ones you keep the same? Has there ever been a concept that students get so confused about again and again? This presentation is packed with exercises in order to test that knowledge and formativelz deal with misconceptions. Ideal to use in a focused one off lesson, or as a tool for surprise plenaries or starters over a longer period of time, the slides here contain real life investigations and data and test students graph plotting skills and planning as well. Essential for all budding scientists! Let us solve this problem once and for all.