Engaging experiments with the next generation of rainwater specialists!

Post by Lorna Devenish

The beauty of working in rainwater harvesting is how quickly people pick up the concept and become enthusiastic about it. Water is such an essential part of life, people grasp how important it is to make better use of it.

Of course, the reality of retrofitting smart rainwater management systems is that it is quite a complex business. But the concepts are beautifully simple, which lends itself really well to engaging with schools and school children.

With this in mind, I had great fun designing my ‘experiment rig’ for my assembly at a primary school in Southwark as part of our OrganiCity EU experiment. I wanted something hands-on the children could get involved in, that wasn’t too complicated, and that would give us a very clear ‘result’.

I settled on trying to demonstrate that rain falling on a hard surface runs off much faster than rain falling on a permeable surface. I had one problem: it all had to be light enough, and compact enough, to transport by train. So real grass turf and paving slabs were out.



My polystyrene “pavement” and “grass” made out of sponges (topped with fake grass for effect) worked a treat. A couple of plastic tubs from the recycling were perfect, and everyone loves those Plui bath toys where you can make it rain at the lift of a finger.

We timed how quickly 10 mL of water ran off the “pavement” and how quickly it ran off the “grass”. They learnt that not all the 10 mL came out of the “grass” – not only had it slowed the flow but it had absorbed some of the water too.

Who knew work could be so much fun?




Keep following us to hear about the art workshop I led with Y5 pupils, to brighten up the tanks in the school and the community.

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