It’s easy to make a crystal snow globe using real crystals of benzoic acid. Benzoic acid is a safe chemical that forms sparkling clear crystals that resemble snowflakes, but don’t melt! This is a great holiday science project that introduces chemistry concepts, including solubility, crystallization, and how to follow a procedure. You’ll want adult supervision for youngsters, but older kids and teens can do this project themselves.
Crystal Snow Globe Materials
You only need a few simple materials to make a benzoic acid crystal snow globe.
- 1 g benzoic acid
- 200 ml water (distilled works best)
- 4-6 ounce jar with lid (baby food or ointment jar)
- Small decorations that fit inside the jar
- Hot glue gun
Benzoic acid is an inexpensive chemical, readily available online. Select color-safe decorations, such as small plastic toys. You don’t have to use a hot glue gun to fix the decoration to the jar, but you can’t use a water-soluble glue because it would dissolve. Alternatives to hot glue include super glue or epoxy glue.
If you want a larger snow globe, use a bigger container and increase the amount of benzoic acid and water:
- 5 g benzoic acid
- 1 L water
Make the Benzoic Acid Snow Globe
- Sir the benzoic acid into the water. Either use hot water to dissolve the powder or else heat the solution to aid dissolving. You can do this in a microwave or over a hot plate or stove. The water only needs to be hot, not boiling.
- While the solution cools, stick decorations to the “snow globe.” Usually, the lid is acts as the snow globe base (jar upside-down), so affix decorations to the inside of the lid. You can glue them into the jar, but might need to use tweezers to position objects.
- As the solution cools, benzoic acid crystallizes to form “snow.” The rate of cooling affects the size and shape of the crystals. Slow cooling produces large crystals that look like snowflakes. Quick cooling forms tiny crystals. If you don’t like the crystals you get, you can re-heat the liquid and try again to get the “snow” you want.
- Pour the liquid and crystals into the jar. Fill the container as much as possible because air pockets can cause the crystals to form clumps.
- Put the lid on the jar. You can seal it with electrical tape or glue.
- Gently shake the jar and enjoy the sparkling snow!
If one of your ornaments detaches from the snow globe, unseal it and pour the liquid into another container. Then, you can do the repair. When you’re ready, just pour the liquid back into the snow globe and seal it up again.
How the Snow Globe Works
The crystals in the snow globe show the effect of solubility. Benzoic acid doesn’t dissolve very well in cool or room temperature water, but if you heat the water, more of the chemical dissolves. The same principle applies to other types of crystals, like rock candy. When you grow rock candy, you have to heat the water to dissolve enough sugar to make crystals.
The shape and size of the snow globe crystals depends on the rate of cooling. In general, larger and more elaborate crystals form from slow cooling or evaporation than from fast cooling. Basically, slow cooling allows more time for molecules to organize to form crystals. The same effect is true of real snowflake formation. The shape and structure of snow crystals depends on air temperature.
Safety
Benzoic acid is used as a food preservative, so it’s a safe chemical for making crystals. But, the powder and solution can irritate skin and mucous membranes. If you touch the chemical or spill some on your skin, rinse it off with water.
It’s safe to rinse leftover liquid down the drain. You can use cooking utensils for this project. Just wash them before using them for food.
References
- Cosmetic Ingredient Review Expert Panel Bindu Nair (2001). “Final Report on the Safety Assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate”. Int J Tox. 20 (Suppl. 3): 23–50. doi:10.1080/10915810152630729
- Maki, Takao; Takeda, Kazuo (2000). “Benzoic Acid and Derivatives”. Ullmann’s Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a03_555. ISBN 978-3527306732.
- Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand.