As the spray leaves the funnel the water in the droplets evaporates leaving only glistening particles of salt,
they rise up into the clouds where they attract water vapour which condenses on the salt particles making the clouds thicker and more reflective.
John Latham and Stephen Salter have calculated that to make enough shiny clouds to control the temperature of the earth they would need to spray 500 kilograms or litres of water per second every year.