One of the birthday gifts my eldest received was a science kit. The science kits are awesome for kids. The Steve Spangler Science creations can come in individual packs or single packs. I have bought these products before and my kids love them. The one my daughter received had a a number of experiments, each one with at least two options. There are crystals that expand but first you need to add the colour tablets in first to colour the water then add the crystals. Watch it fizz, expand and change in colour. There are colour beads that change in different types of light. Snow that expands but it must be measured correctly or it can get slushy! Dry sand even when wet and a dino that expands in water and over a period of time. There is a leaflet that explains why and how it works.
I give this kit a 10 out if 10.