This completely non-toxic powder absorbs up to 500 times its own weight in water and is the 'secret' ingredient used in applications ranging from babies nappies to perpetual growing plants. When exposed to water, the powder transforms into a gel which holds the water for an extended period.

Place a small pile of Hydrogel in the centre of a Petri-dish and add drops of water from a syringe or pipette. The Hydrogel will swell until it can absorb no more water. This can be a simple quantitative experiment by weighing before and after water absorption.

This grade of Hydrogel can also be used in the lab or prep-room to assist the growth of small plants, especially over weekends. The amount added to the soil or growing medium needs to be determined by trial and error.

• Supplied in a 500g bag.