In a laboratory at the U.S. Department of Energy’s Brookhaven National Laboratory, scientists recently witnessed something remarkable: the birth of a cloud inside a metal box.
Tiny glowing specks began to swirl, forming a mist that slowly grew into a small, wispy cloud.
The moment marked the successful testing of a new device designed to help researchers better understand how clouds form and behave.
The device, called a convection cloud chamber, is essentially a one-cubic-meter box that recreates the conditions needed to produce clouds.
While clouds may seem simple from the ground, they remain one of the largest sources of uncertainty in weather forecasts and climate models.
Scientists know that clouds play a crucial role in regulating Earth’s temperature, moving water through the atmosphere, and influencing storms, but many of the fine details of how they form and produce rain are still poorly understood.
Studying clouds in nature is difficult because they constantly change. Researchers have flown instrument-packed aircraft through clouds to collect data, but even during a single flight, conditions shift.
The cloud chamber offers a way to create repeatable experiments in a controlled environment, allowing scientists to isolate specific factors and study them carefully.
To form a cloud inside the chamber, scientists fill the bottom with water and heat it so that warm, moist air rises upward.
The top of the box is kept cold, creating a temperature difference. When the warm air meets the cooler air, the humidity becomes extremely high — even higher than what normally occurs in the atmosphere. This condition, known as supersaturation, is necessary for cloud droplets to form.
Next, researchers introduce tiny particles such as salt into the chamber. In the real atmosphere, these microscopic particles act as seeds that water vapor can condense onto, forming droplets.
The same process happens inside the chamber, producing a stable cloud that can last for hours. Because the chamber’s temperature, humidity, and turbulence can all be carefully controlled, scientists can repeat experiments and compare results more reliably than ever before.
One of the major advantages of the design is its flexibility. Adjustable heating and cooling panels allow researchers to create different types of clouds and conditions. The system can also be expanded in the future to produce larger and longer-lasting clouds, enabling studies of drizzle and rainfall formation.
Measuring what happens inside the cloud without disturbing it is another challenge. To avoid interfering with the airflow, the team plans to use advanced imaging techniques based on light. By tagging particles with fluorescent dyes and illuminating them with lasers, scientists can track how they turn into cloud droplets. Specialized radar and laser instruments will also allow researchers to observe droplet size, movement, and the formation of drizzle in extraordinary detail.
The project required close collaboration among scientists, engineers, and technical staff. Many of the chamber’s components were built in-house, allowing the team to refine the design as they went. The result is one of only two convection cloud chambers in the United States, representing years of experience and innovation.
Beyond studying clouds, the chamber may also help researchers explore other questions about the atmosphere. Potential applications include examining how weather affects energy systems, communications infrastructure, and the spread of tiny airborne particles such as pollen or pathogens.
By creating a controlled “atmosphere in a box,” scientists now have a powerful new tool to investigate the processes that shape weather and climate.
Each experiment inside the chamber could bring researchers closer to answering long-standing questions about how clouds form, why some produce rain while others do not, and how they influence Earth’s future climate.
