Doing density..two nice bits 1) Asked a pupil which was heavier, 1kg of feathers or 1kg of lead - caught them out (they nearly always fall for this). Then produce said items (feathers were a large bin bag of packing chips with a few masses in to make it up to weight) - placed both on balance to show same mass 2) Then brought out transparent bag full of toy balls (from early learning centre) - left a few balls in the bag - scrunched up bag to show low volume (but same number of particles - so more dense. Unscrunch bag - larger volume, same balls, so less dense