It the Christmas season, for one more day at least. Another year has gone by and the Christmas spirit has made the last week a lot of fun. Lights and decorations twinkle in the shorter, dark days, while presents are being bought and wrapped. And who can forget the food? This time of year also marks the beginning of Winter! The classic themes of winter are cold temperatures, glistening frosty mornings, sleek and shiny ice, oh and of course snow! In this molecule of the month post we’re going to look at how to make your own fake snow.
Water, Water, Everywhere
Chemically, snow is nothing more than crystals of ice, the solid form of water. Billions of water molecules joined together in a large network through attractions known as hydrogen bonds. We described all about the hydrogen bonds in snow in a Boom Advent post you can find here.
The problem with waiting for natural snow (especially in the UK) is you often end up waiting a long time! The conditions are never quiet right, and when it does snow it does not settle.
Do It Yourself
But what about creating our own snow? Snow we can have anytime, anywhere! Now, that sounds amazing. We’ve already seen a physical way of making fake snow, but what about a more chemical approach?
As as it’s Christmas, we are treating you to not one, but two molecules this month! We can use both of these molecules to create fake and fun snow. Let us introduce calcium acetate and sodium polyacrylate.
Calcium acetate is an ionic compound containing positively charged calcium cations and negatively charged acetate anions. Acetate also has the name ethanoate and so the compound also has the name calcium ethanoate.
Calcium acetate is a a water solid that is rather soluble in water. It has the chemical formula Ca(C2H3O2)2. The compound is very good at attracting and holding water molecules, making it hygroscopic.
A really simple way to make calcium acetate is to place eggs in vinegar. Calcium carbonate in the egg shells reacts with the acetic acid in vinegar to produce calcium acetate.
A Use Or Two
Calcium acetate helps to lower the amount of phosphates in blood. This is important to help lower blood levels.
Calcium acetate is also a food additive. Adding this compound to food helps to improve its taste and flavour.
One very cool experiment is making a fake snowball using calcium acetate. Please do not try this home as it involves dangerous chemicals and fire, and these two do not always go together well!
Mixing together a solution of calcium acetate with a solution of ethanol produces a white gel. Already, this looks very much like slushy snow. You can squash the gel together to make a snowball.
We have produced solid calcium acetate with ethanol molecules trapped inside!
Snow and Fire
Now, here is the dangerous part, we can set the snowball on fire! In fact, it is possible to handle it while it is burning as long as our hands are wet.
The gel burns because ethanol is highly flammable. Eventually, the fire will go out and you may notice that snowball has shrunk and even turned brown in places!
Here’s a method for how to recreate this for yourself – but remember to be careful.
Making snow with calcium acetate and ethanol is great fun, but also quite dangerous. What about it we want snow that is a little safer to use and perhaps not as flammable?
A much easier way to create fake snow is to use sodium polyacrylate, and mixture it with a little water.
Sodium polyacrylate is an example of polymers. We have already seen examples of polymers and met a similar acryate molecule in superglue. Polymers are very large molecules made from repeating units of a small molecule. Sodium polyacrylate contains repeating units of sodium acrylate. Reacting acrylic acid with sodium produces sodium acrylate. Polymerizing sodium arcylate produces sodium polyacrylate.
The structure of sodium polyacrylate is shown below. The ‘poly’ part of the chemical name means that there are lots of bits all joined together to make a giant molecule. That means polyacrylate is made of lots of acrylates all joined together. The structure in the image shows one unit of acrylate inside the square brackets and then the dotted lines show where one acrylate joins to the one before and the one after! Imagine lots of these units all joined up together in a massive long line.
Sodium polyacrylate is a super-absorbent polymer and is able to absorb a lot of water. In fact, it can absorb up to 100 times its mass in water!
It is for this reason that sodium polyacrylate is the ideal material for diapers. You can also find it in the soil of indoor plants, where it helps to retain water and ensuring the plan has enough moisture.
Mixing sodium polyacrylate with water produces a gel-like substance. Hair gels, hot/cold packs and some soaps all contain sodium polyacrylate!
Making fake snow with sodium polyacrylate is very easy! Sodium polyacrylate is a fine, white powder. However, adding water to some sodium polyacrylate causes it to swell up and expand, producing something that looks very much like snow!
This means you can snow all year long, even in the summer! And it will not melt either. This is why films and TV shows often use sodium polyacrylate for fake snow!
And Now You Snow
Normally, if you want snow you either have wait for the right conditions or go somewhere very cold! But snow is hard to come by and you don’t fancy a trip to the Poles, then there are still plenty of ways to making snow.
The easiest, and safest, way is to mix sodium polyacrylate with some water.
But, if you’re feeling brave and are very careful, then you can make a Californian snowball. Snow and fire don’t usually mix, but with a calcium acetate / water mixture, you can set fire to your snowballs!
From all of us here at Hopefully Nothing Goes Boom – Marcus and Phil – have a great Christmas and a very happy new year 🙂