Trade secrets... making it rain

The great scientist and inventor Nikola Tesla recalls in his biography how he was walking in the Alps one day when he saw how a flash of lightning triggered the storm clouds to start raining. This inspired him to envisage a future where giant man-made electrical machines would be used to control the weather. Although Tesla did invent generators that could create millions of volts, so far we have not yet been able to use them to make rain to order. Although physicists and engineers can’t yet control the clouds, chemists believe they can by using a process called ‘cloud seeding’.

There are areas in the world where the annual rainfall is a crucial factor in determining if people are able to live in the region. The problem is not always simply a lack of clouds. Sometimes clouds form, but the local geography doesn’t always create the right conditions for the clouds to produce rain. There are other regions where clouds bring too much rain. In both cases scientists have been able to force the clouds to rain – to ‘seed’ them – to drop their water.