The ionising effect of radiation can be seen using an ionisation chamber and pico-ammeter. Ions created by the ionising radiation are attracted to the oppositely charged electrode and produce a current proportional to the number of ions discharged at the electrode.A cloud chamber contains air supersaturated with e.g. alcohol vapour and kept at a very low temperature. When air is ionised by ionising radiation the vapour condenses into droplets and can be seen as a visible tracks. Alpha particles from the same source produce straight tracks of the same length. Beta particles form wispy tracks which are fainter than the tracks from alpha particles.