Create a Storm Glass (Instrument for Weather Prediction)





Introduction: Create a Storm Glass (Instrument for Weather Prediction)

About: I like turning boring things into awesome things! Usually on video.

Well, it snowed today! +1 for Storm Glass forecast accuracy.

The Storm Glass was first invented in the mid 1700's, and soon made it's way into ships and harbors around Europe to help give warning of approaching bad weather. It gained the most fame through Admiral FitzRoy who used a Storm Glass on the voyage in which he and Darwin traveled to the Gal√°pagos Islands. As such, the instrument is sometimes called a 'FitzRoy Storm Glass'.

Due to the use of vodka rather than pure ethanol and water, the proportions I use to make the Storm Glass in my video breaks somewhat from the traditional ratios, but the recipe is balanced to achieve the same effect as the original. Fortunately, the chemical solution does not require extreme precision to work properly.


  • Vodka, 100 Proof (50% Ethanol) - 300 mL
  • Camphor - 28g (1oz)
  • Potassium Nitrate - 10g
  • Ammonium Chloride - 10g

Some of these chemicals may be difficult to obtain in certain parts of the world, but if Camphor can be found it's possible that Potassium Nitrate or Ammonium Chloride could be substituted for other soluble salts, such as Sodium Chloride (I have not tested this).

To read a Storm Glass for weather prediction, here is a description from the book Pharmaceutical Formulas by Peter MacEwan, published in 1908:


The changes of the solution signify the following:

  • Clear liquid : Bright weather.
  • Crystals at bottom : Thick air, frost in winter.
  • Dim liquid with small stars : Thunderstorms.
  • Large flakes : Heavy air, overcast sky, snow in winter.
  • Threads in upper portion of liquid : Windy weather.
  • Small dots : Damp weather, fog.
  • Rising flakes which remain high : Wind in the upper air regions.
  • Small stars : In winter on bright, sunny days, snow in one or two days.
  • The higher the crystals rise in the glass tube in winter the colder it will be.


The crystals within a Storm Glass will dissolve and solidify all on their own as the temperature changes day to day. If you would like to start fresh with completely clear liquid and watch the crystals form rapidly, the glass can be placed in a bowl of warm water for 10 minutes to dissolve old crystals completely. Remember to loosen the lid before doing so to prevent excess pressure from building inside.

For further reading see:

Thank you for reading! If you cannot view the above video please view this page from a desktop computer. Instructables doesn't always display embedded videos properly on mobile devices. A complete time lapse of a Storm Glass can be viewed on my YouTube channel.



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Is the "recipe" scalable? Lets say that I wanted to make a 20L Storm glass, would I just multiply all the quantities by 66.7?

On my list......will be making one soon

Just made it! Added some blue food coloring for a more dramatic effect!

I will use it indoors, next to a window. Somehow this works just as well. Maybe also barometric pressure has an effect to the weather glass. Or maybe the rate the temperature changes instead of the temperature itself.

Or maybe it's just magic... ;-)


This is so cool!

It snowed here today and I wish I had one of these.

It would be soon cool to watch the crystals snowing.

What kind of glass did you use in the video? I really like how clear and smooth the outside is. I would like to use something like this instead of a mason jar, any tips?

4 replies

You might find a candy jar with relatively smooth sides and a good lid.

It was a vase from Walmart. The only problem with it was it didn't come with a lid. I had a pipe tobacco tin that just happened to have a lid just the right size so i used that.

Yeah I figured the glass wouldn't be too hard to find I was more concerned about the lid. How tight does it need to be?

This is so freakin cool! I had never heard of these before. Just one question. Would you recommend taller thinner containers, or shorter wider ones. Which ones have the better effect?

1 reply

I dont think it matters. It's a chemical reaction, and reacts to barometric pressure (with accuracy affected by temperature). They are, in reality, only about 30-50% accurate.

That is so cool! My son-31 and a weather fanatic-and I watched the demonstration and were amazed. Going to have to make one.

Unless you are interested in the weather inside. I think it needs to be exposed to the weather you are trying to predict.

This sounds so cool! Thank you for sharing!

My grandfather had this, I also have tried to build one before, but with no success. I'll try your recipe for sure!

Amazing as always ,

Forget the TV weather man i'll just watch this all day :-)

Well that's just magic, bah humbug to science, that is clearly magic. Ok it's probably really awesome old world science, but you can see why it seems like magic right? That is really awesome, if nothing else just to watch.

1 reply