What it is
The storm glass is an "instrument" said to predict the weather. It is a glass orb (or container; mine is a raindrop), airtight, with a clear chemical solution suspended inside. I'm not entirely sure what it's made out of, but the gist of it is that crystals will grow within the solution or precipitate; and it will predict different forms of weather, based on the formation of the crystals.
I misplaced the little pamplet that came with mine and explained how it worked, but the Wikipedia page seems to have documented it:
- If the liquid in the glass is clear, the weather will be bright and clear.
- If the liquid is cloudy, the weather will be cloudy as well, perhaps with precipitation.
- If there are small dots in the liquid, humid or foggy weather can be expected.
- A cloudy glass with small stars indicates thunderstorms.
- If the liquid contains small stars on sunny winter days, then snow is coming.
- If there are large flakes throughout the liquid, it will be overcast in temperate seasons or snowy in the winter.
- If there are crystals at the bottom, this indicates frost. If there are threads near the top, it will be windy.
Review
I got mine for Christmas, and at first I thought it was the most amazing thing -- what a nifty little device to have sitting on my desk! It seemed to be accurate; there were crystals at the bottom, and it was "frosty" outside, so to speak. However, come spring, the formation of the crystals never changed, nor did they with summer, or the now-present fall. There's people in the Amazon reviews that say it works perfectly. Maybe the reviews were bought, maybe my room doesn't get enough ventilation, there's no way to know. What I do know is that mine is bunk and it's not very well documented to begin with, so be wary if you decide to try it out for yourself.