Surprising yet simple natural behavior is drawing fresh attention from scientists, as new findings show that spraying tiny droplets of water can produce flashes of light and trigger chemical changes in the surrounding air—all without using any electrical device. This unexpected outcome could help explain certain weather phenomena and offer insight into how life might have started on our planet.
Professor Richard Zare and colleagues at Stanford University discovered that when clean water is sprayed, it naturally splits into small droplets that carry either a positive or negative charge. When these oppositely charged droplets move close together, they release a spark-like discharge, which the team calls “microlightning.” Their findings appear in the journal Science Advances.
Interestingly, this light-producing effect is more than just a visual display. As the droplets separate in the air, the smaller ones tend to gain a negative charge while the larger ones stay positively charged. When they come close enough, they create a quick and energetic reaction that lights up and can affect nearby gas molecules. Put simply, this small-scale lightning can trigger chemical changes much like a storm’s lightning—but in a smaller, more manageable way that can happen more frequently.
Creatively exploring further, the scientists mimicked the conditions of early Earth by spraying water droplets into a space filled with gases such as nitrogen, methane, carbon dioxide, and ammonia—gases thought to be common long ago. What followed was the creation of basic organic substances important to life. These included hydrogen cyanide, glycine, and uracil, which are building blocks of proteins and genetic material. According to the team, these transformations happened almost instantly, showing just how effective this method is.
Professor Zare emphasized, “We have demonstrated that water droplets in a spray generate luminescence, which we call microlightning, when they split into smaller droplets in the absence of any external voltage.” This statement underscores how a basic process like droplet formation can result in something remarkably energetic.
Utilizing advanced tools, the team used sensitive detectors and high-speed cameras to track the changes caused by these droplets. Their controlled tests confirmed the release of light and the creation of electrically charged particles—known as ions, which are atoms or molecules with an electric charge—during the droplet process. Notably, the small lightning had enough energy to affect complex gases like benzene, a chemical found in crude oil, and even rare ones like xenon, a noble gas used in lighting and imaging, demonstrating how powerful these miniature sparks can be.
As Professor Zare put it, “This microlightning can excite, dissociate, or ionize the surrounding ground-state molecules, causing chemical reactions to occur in the gas surrounding water microdroplets.” This clarifies the wide range of potential chemical effects resulting from the sparks.
Naturally occurring environments might already be full of such small sparks. Events like ocean waves crashing or mist forming near waterfalls could be common settings for microlightning. While large lightning strikes have long been seen as major contributors to shaping early life, this study points to a more frequent and gentler way for the same chemical building blocks to form. As the researchers explain, this observation offers an interesting explanation for the unique reactivity at the water-gas interface—the surface where water meets air, a zone known for unusual and often heightened chemical activity.
Looking further ahead, Zare noted, “We suggest that this common energy source may provide a route for creating C–N bonds from abiotic gas molecules expected to be present on early Earth.” This adds another layer of relevance, connecting a natural and frequent process with theories on the origin of life.
Posing exciting possibilities in environmental science and the origins of life, this study suggests that powerful forces for change are not always dramatic or large. They may exist quietly in the spray of water or a humid breeze. This discovery gives researchers a new angle to explore how tiny natural processes might lead to significant changes—whether in cleaning air pollution or understanding the very first steps toward life.
Journal Reference
Meng Y., Xia Y., Xu J., Zare R.N. “Spraying of water microdroplets forms luminescence and causes chemical reactions in surrounding gas.” Science Advances, 2025; 11: eadt8979. DOI: https://doi.org/10.1126/sciadv.adt8979
