Frozen Bubbles at Mount Washington Observatory: Video and Science

On 24 January 2011, the weather observers at Mount Washington Observatory in New Hampshire took a break from their instruments and went outside to blow soap bubbles. In the bitter summit cold, each bubble turned into a tiny ice sculpture, with feathery crystals racing across its surface before the film froze solid. Their short video shows the whole process up close.

Mount Washington Observatory: a weather station on a windy summit

Founded in 1932, Mount Washington Observatory is a private, non-profit scientific and educational institution that keeps weather records on the summit of Mount Washington, at about 6,270 ft (1,910 m). It is housed in the Sherman Adams building, named after a former governor of New Hampshire.

The summit is famous for extreme weather:

• Wind: on 12 April 1934 observers measured a gust of 231 mph (372 km/h), the highest wind speed recorded anywhere in the world until 1996.
• Cold: the record low is −47 °F (−44 °C), and the January daily mean is just 5.8 °F (−14.6 °C).
• Summer: even July averages only 49.9 °F (9.9 °C), and the record high is 72 °F (22 °C).

With winter temperatures like these, a soap bubble on the summit freezes in seconds.

The frozen bubbles video

For the demonstration, the crew tried several places around the Sherman Adams building. In full wind a bubble bursts or blows away, so they looked for sheltered corners. In one spot the bubble froze slowly enough to watch the crystals grow. In a colder spot the change happened much faster, and the bubble iced over almost at once.

Why soap bubbles freeze in patterns

The swirling crystals have a scientific explanation. In 2019 Jonathan Boreyko and his team at Virginia Tech published a study in Nature Communications on how soap bubbles freeze, and they called the result the “snow globe effect”.

When a bubble rests on a cold surface, its bottom freezes first. The freezing releases latent heat, which slightly warms the liquid next to the ice. That warmer liquid flows up the bubble wall toward the top. As the flow strengthens it tugs at the freeze front, breaking off tiny ice crystals that slide across the film and keep growing as they go. It looks like many freeze fronts at once, but it is a single front shedding crystals. Caltech physicist Kenneth Libbrecht described it as a feedback loop: freezing creates liquid flows that speed up freezing.

How to make frozen bubbles at home

The summit crew shared their bubble mixture:

• 3 teaspoons of dish soap
• ½ to 1 teaspoon of sugar
• 1 to 2 teaspoons of hot water

Mix gently so you do not whip up foam in the container. Pick a calm, very cold day, choose a spot out of the wind, and let the bubble settle on snow or a cold surface. Watch from close range: the crystal pattern forms in just a few seconds.

Related reading

• Angela Kelly’s close-up bubble photographs
• another cold-weather bubble video
• Abraham Lake’s Ice Bubbles: Layers beneath the Surface
• Roof Ice Falling at a Lodge in Grapevine, Texas
• The Ilulissat Calving Sequence in Chasing Ice

Sources