Investigate why things float or sink.
Introduce the idea of formulating and testing hypotheses.

• 1 large, waterproof container. E.g. a bucket, basin, or watertight box. A bath or sink will also work fine.
• A variety of objects of different shapes and sizes, and made out of different materials: stone, metal, plasic, wood. E.g. metal, plastic and wooden spoons of similar sizes; different size spoons; metal and plastic bottle tops; stones; corks; matchsticks.
• Plasticine or play-dough.
• A small plastic tub that fits in the big container.

Investigate what seeds and plants need to grow.
Introduce the basic idea of a controlled trial.

• cress seeds
• 4 trays (plastic food trays are perfect - remember to wash them throughly first!)
• 2 cardboard boxes (big enough for the trays to fit in)
• 4 pieces of kitchen roll, or enough cotton wool to line each tray