The 15th of July is St Swithin’s Day. According to legend, the weather on this day tells us what the weather will be like for the next 40 days. Will it be sun or rain? You can see a bit of how the weather works by building your own miniature biome.
A biome is a habitat, including all the animals and plants that live there. In a biome everything is recycled; water evaporates and then falls as rain, oxygen and carbon dioxide are made by some living things and used up by others, dead leaves are food for bugs. You can make your own biome in a bottle that allows you to see this in miniature. Any plants in the biome should stay alive for quite some time without needing to add water as the water will be constantly recycled. Some people have made bottle biomes like this that have kept going for 40 years!
To make your biome, you need a large see-through plastic container that can be sealed. This could be a plastic mixing bowl with cling film on the top or you could cut a large plastic bottle in half (grown up job!) and stick it back together when you’re done. Make your garden with soil, pebbles, small plants and anything else that you like! Make sure you water it before you seal it up. Sealing it acts like our atmosphere to keep the water in instead of it drifting away into outer space.
Leave your biome for a few days and keep checking on it. You should be able to see how water evaporates from rivers and lakes and how rain forms and falls. Your very own weather system in a bottle!
So is the legend of St Swithin’s day really true? Well, according to the Met Office there has never been a 40 day drought or 40 days of continuous rain in the UK since records began, so probably not! I’m still hoping for a sunny summer though…
Emma Ranade spends most of her time exploding things and experimenting at Fab Science birthday parties, holiday clubs, home education groups and school workshops. www.fabscience.co.uk 07799 624777