Monday, January 11, 2016

It's a Winter Science Extravaganza with Snow, Polymers, and Arizona Midday!





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!

This chart is attributed to Caltech Physics Professor Kenneth Libbrecht

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.


Materials Needed:

Borax (you can find this in your laundry aisle at the grocery store)
Pipe Cleaners
Clean jar (mason jar or other wide mouthed jar)
1/4 cup of hot tap water
Almost boiling water
Pencil
String (Yarn, string, or nylon fishing line)

Spoon
Coffee filter or newspaper


Instructions:

1. Heat a kettle or pot of water until it is almost boiling.

2. Add some hot tap water to the jar. This will allow the jar to come to a higher temperature without shattering.

3. Bend your pipe cleaner into any shape you like! Just make sure it won't touch the bottom or the sides of your container. Use a string or nylon fishing line to tie your shape to a pencil. Tape it to the pencil to secure it. (Note: String will allow a string of crystals to build along your shape. Fishing line will keep all the crystal growth to your pipe cleaner.)

4. When the water is almost to a boil, turn the heat down and SLOWLY add the water to the jar. You'll want to add enough to completely submerge your pipe cleaner. 

5. 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 super saturated!

6. Put your pipe cleaner shape into the jar, with the pencil lying over the mouth. Cover the opening with a coffee filter or newspaper to keep out any dust particles!

7. Within an hour, you should start to see some action, leave it overnight and see what happens!


GIANT ALUM CRYSTALS

Another fun crystal growing experiment involves isolating Alum crystals and build your own diamond look-a-likes with them! Alum is the common name for Potassium Aluminum Sulfate, which in powder form, is traditionally used in baking, both in baking powder and in pickling (it's used to make pickles crispier!). You can read more about it here, and you can find its powdered form in the spice aisle of your grocery store.

The best way that I've found to grow these is to start with a seed. Then you can go from there, growing your beautiful Alum crystals!

Materials Needed: 
2 glass jars
1/2 cup of almost boiling water 
2 1/2 Tbsp of Alum powder 
Coffee filter or newspaper 
Clean spoon for stirring 
Nylon fishing string

Instructions: 


1. 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. 

2. Cover your jar with the coffee filter or newspaper and let it sit over night. By the next morning you should see some little crystals packed together on the bottom of you jar!

These are how the seed crystals looked after one night!

Picking your seed crystal and growing it 

3. 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. 

4. 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. 

5. 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!


EXPERIMENT! 
Does the temperature of the water affect your crystal growth?
Does the container you use to grow your crystal have an affect 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!



Note: While this polymer is non toxic, is biodegradable, and doesn't break town with toxic byproducts, there are still some considerations to be made. Don't inhale this, eat it, or get it in your eyes! For disposal, please use the garbage, as large quantities of this gel (it is super absorbing after all), may clog your drain!
Materials Needed:

Disposable infant diapers
Scissors
Water
Plastic ziplock bag
Small glass jar, bowl, or container
Piece of paper

Instructions:

1. 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.

2. 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.

3. Start peeling off the cotton layer, making sure to collect any particles that fall off on to your paper.

4. 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!

5. Take the cotton layer out of your bag and dump the powder into your container. Add the powder collected on your paper as well.
6. Add a splash of water and swirl it around, and see what happens! Try turning the cup over, does any water come out?

EXPERIMENT! 

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...




Happy Exploring!

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