Halloween can tend to bring an abundance of spooky special effects, from dry ice to creepy crawling fog displays. However, what you may not know about these special effects is that the main component in their creation is carbon dioxide (CO2).
While CO2 plays an integral role in producing theatrical smoke and fog, if not handled carefully with common sense, it can be dangerous.
How are Halloween special effects created?
Special effects fog or smoke is created by mixing glycerin and distilled water, then heating it to the point of evaporation. When used with evaporating blocks of CO2 "ice" it creates a thicker, more consistent display. In addition, liquid CO2 stored in compressed cylinders can also be used in conjunction with a fog machine to produce "low-lying" fog effects. When liquid CO2 is used, it essentially "chills" the fog, and the result you see is the thick cloud that stays within a few feet of the ground - perfect for capturing the "spooky" Halloween effect.
The benefits of using a carbon dioxide over a glycerin-based mixture is that you can't taste or smell the CO2 gas. It will quickly disappear into the air. However, larger smoke and special effects created with liquid CO2 have been known to create negative health effects if proper CO2 monitoring is not present.
Aside from just creating fog, solid blocks of frozen CO2 called dry ice are used for experiments. As opposed to the liquid form, the solid form of CO2 can be dropped into near boiling water to instantly produce a gas, condense the water vapor and creating a thick white fog.
CO2 Dry Ice and Fog Safety
While Halloween may be the perfect time to use dry ice and fog for real eye-catching science, it is good to remember that under normal conditions CO2 is a gas. As it changes from a liquid or solid state to a gas, it expands by several hundred times in volume. It can easily lower the oxygen level in an enclosed area which can lead to dizziness, fatigue, headache and in some cases, fainting and death.
To ensure your safety, dry ice should always be handled with care. CO2 has to be cooled to at least -109.3°F to freeze into dry ice. When handling, gloves or tongs should always be used to avoid severe freezing of skin and dry ice burns.
In addition, it is never wise to place dry ice in a sealed or closed container. As it melts into a gas it expands and can cause an explosion.
CO2 Safety Monitors
To protect yourself and others near high levels of CO2 in theatrical or special effect experimentation, consider a handheld or desktop CO2 monitor that can quickly warn you if CO2 reaches dangerous levels in enclosed areas where CO2 buildup may cause personal injury.
More Halloween Fun
For more Halloween fun with CO2, here's a list of our favorite experiments:
- Spooky expanding ghost experiment
- Oozing pumpkin CO2 volcano experiment
- Giant dry ice CO2 bubble sphere
- Boo bubbles and exploding pumpkins
- Low lying CO2 spooky fog effects
Let's face it, who does not like a smoking pumpkin or a creepy low-lying fog upon trick-o-treating? It's easy to make your favorite Halloween experiment and gain all the "oohs" and "aahs". Just remember that safety comes first and ensure you and those around you are always protected.