What Is the Difference Between Steam and Smoke?

Use the color of the cloud and how quickly it dissipates to determine whether it is smoke or steam.

ThoughtCo / Anne Helmenstine

Can you tell by looking at this plume from this factory whether it is releasing smoke or steam? Both smoke and steam can appear as clouds of vapor. Here's a closer look at what steam and smoke are and the difference between them.


Steam is pure water vapor, produced by boiling water. Sometimes, water is boiled with other liquids, so there are other vapors with the water. Ordinarily, steam is completely colorless. As steam cools and condenses it becomes visible as water vapor and can produce a white cloud. This cloud is just like a natural cloud in the sky. It is odorless and tasteless. Because the humidity is very high, the cloud may leave water droplets on solids that touch it.


Smoke consists of gasses and soot. The gasses typically include water vapor, but smoke differs from steam in that there are other gasses, such as carbon dioxide and sulfur oxides, plus there are small particles. The type of particles depends on the source of the smoke, but usually, you can smell or taste either the soot or some of the gasses from the smoke. Smoke may be white, but more commonly it is colored by its particles.

How to Tell Smoke and Steam Apart

Color and odor are two ways to distinguish smoke and steam. Another way to tell smoke and steam apart is by how quickly they dissipate. Water vapor dissipates rapidly, particularly if the relative humidity is low. Smoke hangs in the air since the ash or other small particles are suspended.

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Your Citation
Helmenstine, Anne Marie, Ph.D. "What Is the Difference Between Steam and Smoke?" ThoughtCo, Aug. 25, 2020, thoughtco.com/what-is-the-difference-between-steam-and-smoke-606777. Helmenstine, Anne Marie, Ph.D. (2020, August 25). What Is the Difference Between Steam and Smoke? Retrieved from https://www.thoughtco.com/what-is-the-difference-between-steam-and-smoke-606777 Helmenstine, Anne Marie, Ph.D. "What Is the Difference Between Steam and Smoke?" ThoughtCo. https://www.thoughtco.com/what-is-the-difference-between-steam-and-smoke-606777 (accessed March 24, 2023).