Save this simple science activity to try with your little one! All you need is water, oil and food colouring! . We used baby oil because it is clear but you can do this with other types of oil like vegetable or sunflower oil. . Simply pour a thin layer of the oil over the base of the PlayTRAY lid- just enough to cover it. Mix food colouring of your choice into water. It’s worth using quite concentrated food colouring so that the colours show up well. Then use droppers to transfer the water to th