You know that old chestnut...are we doing a practical today? Can we make things explode? I have one lesson left with my year 7 group when I can go off topic and do something different. There's plenty of demos to do, elephant toothpaste, mentos, methane bubbles etc but any ideas for anything that they can do themselves which in my eyes is completely safe but in their eyes is exciting and a bit risky? I'm sure I know plenty but end of term brain has set in! Many thanks!