In color theory, a purple is defined as any non-spectral color between violet and red (excluding violet and red themselves). The spectral colors violet and indigo are not purples according to color theory but they are purples according to common English usage since they are between red and blue.
Dry ice fog is a thick, dense, low-lying fog created exactly the way fog in nature is. created, by condensing water vapor out of the atmosphere. We use dry ice (the. solid form of carbon dioxide) to condense the water vapor out of the air. Dry ice. fog contains no chemicals, glycols, or oils, and is truly a water based fog.
When you place dry ice into warm or hot water, clouds of white fog are created. This white fog is condensed water vapor, mixed in with the invisible CO2. The extreme cold causes the water vapor to condense into clouds. The fog is heavy, being carried by the CO2, and will settle to the bottom of a container.