Sadie Mills, NIWA
The Cloud Condensation Nuclei (CCN) Counter acts like a cloud. It draws in air from the pipe we pictured, through a column which is saturated with water vapour. Sean introduces a temperature gradient into the column so that the warm air at the top of the column increases the water vapour, and as the air cools lower in the column the water vapour condenses onto the particles in the column. The condensed water then passes through a laser. The laser determines the number and size of activated aerosols in the sample.