Today Charlotte dived into the science kit I bought in TKMaxx a few weeks back for a pittance. She has now used vinegar and bicarb to blow up a balloon, seen iron filings line up to a magnet and made a zeotrope.
Her favourite bit was looking at liquid density. This was, basically, carefully adding different liquids to her new test tube (she feels like a real scientist now) to make layers. You then drop things in to see which level they sink to. I reckon this is just as easy to do without a science kit, as the main ingredients all came from my kitchen. It seems like a great way to allow kids to mix up all kinds of liquids and make a bit of mess without getting in trouble.
washing up liquid
It also contains a lump of clay, a marble and a paperclip at this stage. It all got a bit messy after that...