The term “fake snow” is ambiguous, as its temperature depends entirely on its composition and intended purpose. The materials used fall into two distinct categories, each with fundamentally different thermal properties. One variety is frozen water and is therefore very cold, while the other is a polymer-based material that maintains a temperature close to its surroundings.
Cold Fake Snow: The Machine-Made Variety
The type of snow used extensively in winter sports, often called technical snow, is undeniably cold because it is made purely from frozen water and compressed air. Water is highly pressurized and atomized into fine droplets, which are then mixed with compressed air containing ice-nucleating particles.
For this process to work effectively, the environmental conditions must be below freezing, typically requiring a wet-bulb temperature of about -2.5 degrees Celsius (27.5 degrees Fahrenheit). The wet-bulb temperature is a measurement that accounts for both the air temperature and the relative humidity, providing a precise indicator of the atmosphere’s ability to freeze water.
The resulting product is a dense, granular form of ice that is often more durable than natural snow, which is beneficial for maintaining ski resort bases. This durability results from the machine-made flakes being simpler, more spherical ice pellets rather than the six-armed dendritic structures found in natural snowflakes.
The Room-Temperature Kind: Decorative and Polymer Snow
The other common variety of fake snow is the non-cold type used for indoor decorations, window displays, and special effects in film and stage productions. This material is typically made from synthetic polymers, most famously sodium polyacrylate, or from materials like paper, plastic flakes, or soap. Unlike the machine-made variety, these decorative options are designed to be thermally neutral, meaning they simply reflect the ambient temperature of the room.
Sodium polyacrylate is a superabsorbent polymer that expands dramatically when mixed with water, absorbing up to 300 to 800 times its own weight to create a fluffy, white mass. While this material does not feel inherently cold like ice, it can sometimes feel cool to the touch due to evaporative cooling.
As the water within the polymer structure slowly evaporates, it draws a small amount of heat from the polymer’s surface and the surrounding air, creating a temporary cooling sensation. These decorative snows are preferred for indoor use because they do not melt, allowing them to maintain their shape and appearance indefinitely.
The Physical Science of Fake Snow Temperature
The fundamental difference in temperature between the two types of fake snow is rooted in the physics of phase change and latent heat. When ice melts, it must absorb a large amount of energy from its surroundings, known as the latent heat of fusion, without changing its temperature.
For water, approximately 333.55 kilojoules of energy are absorbed for every kilogram of ice that melts at zero degrees Celsius. This constant absorption of heat is what allows a pile of snow or ice to maintain its zero-degree temperature for an extended period, even if the ambient air is warmer. Conversely, decorative polymer snow is a solid material, not a frozen liquid, and does not possess a melting point near room temperature. Because there is no phase change occurring, the polymer simply equilibrates to the ambient temperature of the environment without absorbing or releasing large amounts of latent heat.
Safety and Environmental Considerations
Technical snow, while largely consisting of pure water, is an incredibly resource-intensive product, requiring vast amounts of water and energy for its production. Some snowmaking operations historically used additives, such as protein-based nucleating agents, to encourage freezing at slightly warmer temperatures. The resulting snowpack is often denser and harder than natural snow, which can increase the risk of injury for winter sports participants due to the firmer surface. Environmental concerns also include the high energy consumption and the possibility of altering local water cycles and soil composition underneath the artificial snowpack.
Polymer-based decorative snows, such as sodium polyacrylate, introduce a different set of environmental issues despite being generally considered non-toxic for human contact. Since these materials are plastics, they are not readily biodegradable and can persist in the environment for decades. Improper disposal, such as washing the material down a drain, can lead to severe plumbing clogs due to the polymer’s ability to absorb water and swell tremendously. Furthermore, if released into natural habitats, the non-biodegradable polymer can act similarly to other plastic pollutants and potentially affect wildlife and local vegetation.