Hey, Phoenix! Did you catch us on Arizona Midday on NBC Channel 12? We took advantage of the brisk weather and brought in some winter science to the studio! You can find the experiments we did, as well as the explanations behind them, below! First we’ll focus on growing your own crystals, then we’ll talk about super absorbent polymers and how to make your own at home!
The Science of Snow
We don’t get a lot of snow in the lower desert, and we certainly don’t get it in Phoenix very often. However, we can still learn a lot about snow, ice, crystal formations, and make our own “snowballs” in our kitchen with some home chemistry experiments!
First, let’s take a look at how snow forms. It starts high up in the sky when the temperatures of the atmosphere falls below freezing. As water vapor cools, it can occasionally latch onto an impurity, like a speck of dust. It will begin to freeze, forming an ice crystal. As the heavy ice crystal falls to the ground, it will build crystal structures on its arms to form a snowflake! The size, shape, and patterns of the snowflake all depend on the temperature, humidity, and changing wind patterns as it falls to the ground. The shape can change by the second as these variables change during its fall!
The formation of a snowflake, how the crystal itself forms and continues to grow, begins in a process called nucleation. This is when the ice grows off of a particle, and as water vapor sticks to it, the atoms form a continuation of the crystal structure as it freezes and the water evaporates.
You can mimic this process at home, with the growth of your very own crystals! You can build your own crystal snowflakes, hearts, or any other shape you’d like to make!
BORAX CRYSTAL DECORATIONS
Note: Because you are working with a super-saturated solution, you will need to dilute the solution before disposing of it! I dilute it with hot water, and then run hot tap water continuously down the drain for several minutes.
Clean jar (mason jar or other wide-mouthed jars)
1/4 cup of hot tap water
Almost boiling water
String (Yarn, string, or nylon fishing line)
Coffee filter or newspaper
Note: This post contains affiliate links to products.
Heat a kettle or pot of water until it is almost boiling. Add a small amount of water to the jar, which will allow your jar to come to a higher temperature without shattering. After about 15 minutes, slowly add the rest of your water to the jar, filling it until there is about 3″ from the top of the water to the top of the jar.
Then, add your Borax! You’ll want to add 1 Tbsp at a time, stirring until it dissolves. Keep adding Borax and stirring until you can’t dissolve any more into the water. We used about 10 Tbsp per 2 cups of water. You’ll want to keep adding Borax and stirring until you can no longer dissolve any into your solution. Once you start seeing Borax particles settling on the bottom of your cup, you’ve made your solution supersaturated!
Lay your pipe cleaners out in front of you. Take one of the pipe cleaners and cut it into thirds.
Near the bottom of the long pipe cleaner, start wrapping your small pieces around it, bending it in half to make an “x” shape. Do the same with the remaining two pipe cleaners, until you have a snowflake shape!
Take the free end of your long pipe cleaner, and wind it around your pencil. Hold it up to the outside of the jar to make sure that the snowflake will not touch the bottom or the sides of the jar. Wind the pipe cleaner over the pencil until the bottom is clear, and trim the sides of your snowflake if necessary. Then, put your pipe cleaner shape into the jar, with the pencil lying over the mouth. Make sure the pipe cleaner does not touch the bottom of the jar.
Within an hour, you should start to see some action, leave it overnight and see what happens!
GIANT ALUM CRYSTALS
Nylon fishing string
Take your 1/2 cup of almost boiling water and pour it into a clean jar. Add your Alum powder to it. You’ll want to do this slowly,1 Tbsp at a time, stirring to dissolve. When you can’t dissolve any more Alum, you’ve made a super saturated solution! You’ll know this happens when you see some of the powder sitting on the bottom of your jar when you’ve stopped stirring.
Cover your jar with the coffee filter or newspaper and let it sit overnight. By the next morning, you should see some little crystals packed together on the bottom of your jar!
Picking your seed crystal and growing it
Slowly pour the solution out into your other clean jar, being careful to filter out the crystals, as they will compete for growth with your seed crystal.
Take a pair of tweezers and pick out the largest and best formed crystals. Then tie them to a length of nylon fishing line. If you use yarn or string, crystals will begin to form along that as well, which will take alum away from your seed crystal.
Tape or tie the fishing string to a pencil, adjusting the length so that your crystal is suspended just above the bottom of your jar. Then lower your seed crystal into the new jar, with the super saturated solution.
Observe your crystal over the next few days. If you start to see crystal growth on the sides or bottom of your jar, remove your crystal, pour your solution into a clean jar, and lower your crystal in the solution. This way, you can ensure there are no other crystals competing for growth!
Does the temperature of the water affect your crystal growth?
Does the container you use to grow your crystal have an effect on its growth? Try a plastic cup, Tupperware, an empty soup can, and a glass jar! Record your observations over the next few days and note any differences in your crystal growth.
By growing these awesome crystals at home, you can explore topics like winter science, chemistry, and geology! For more on the chemistry and geology aspects, as well as other crystal growth experiments (and a microscopic peek at nucleation!), check out our post on “A Look Inside The Crystal Shard“.
SUPER ABSORBENT POLYMERS! INSTANT SNOW POWDER AND DIAPER GEL!
Now that we’ve examined how snowflakes are formed and crystals are made, it’s time to talk SNOW! On Arizona Midday, we used a super absorbent polymer, an “Instant Snow Powder”. There are a lot of different names for these on the market, but they’re all essentially the same thing. It’s a non-toxic powder called Sodium Polyacrylate that, when mixed with water, expands to 100 times its size in a super fast water absorption!
You can purchase these powders online, in hobby stores, or in your local teaching supply stores. However, since these polymers are a derivative of the super absorbent polymers found in baby diapers, you can experiment using those too!
Disposable infant diapers
Plastic Ziplock bag
Small glass jar, bowl, or container
Piece of paper
Working over your piece of paper, cut off the ends of the diaper, as well as the elastic sides. You’re going to be working with the part of the diaper that absorbs wetness. Discard everything else.
You should now be able to see that the diaper has three layers. The two outer layer and a sort of cotton inner layer. Pull off the top layer.
Start peeling off the cotton layer, making sure to collect any particles that fall off onto the paper.
Place the cotton layer (or pieces) into your bag. Puff up the bag a bit and seal it. Then shake it until you’ve collected the polymer pieces at the bottom of the bag!
Take the cotton layer out of your bag and dump the powder into your container. Add the powder collected on your paper as well.
Add a splash of water and swirl it around, and see what happens! Try turning the cup over, does any water come out?
Does filtered water change the absorption rate and quality?What about temperature?
Use different liquids like juice, coffee, soda, and vinegar!
What happens if you add different particles to your solidified gel? Try making a few samples and stir salt, sugar, and baking soda into each of them. Make sure you keep one without any added materials to use as your control!
There is a lot of fun to be had in exploring the world around you! Science is a way of learning, it’s a way of looking at the world, and it’s an incredibly fun adventure. Start asking questions about the world and experiment to find your answers! See what others have done and compare your results! Have fun and as always…