Welcome to the Crystal Adventures!

Welcome to our Crystal Adventures! Together we would like to take you on an adventure to explore the wonders of crystals with activities involving sugar, chocolate, snow and lego. Our Crystal Adventures form part of the Cambridge Festival, and together we will explore what crystals are, what they look like, how they grow and discover what's inside them.

In this page you will find four activities that start with our Molecules at Home activity which will introduce you to three crystals that are hiding in our houses, all you need to do is find them!

But, before we start lets go on a short journey together to discover what a crystal is in our short video...

Thumbnail of the introduction video on YouTube

Watch our introduction video on YouTube by clicking on the image. Subtitles are available clicking on the icon.

Molecules at Home

Detective needed: molecules wanted! Chemical substances are hiding in plain sight in our houses: can you help us find them? To complete this task, you will need to fill in an identikit for them, by using our database of crystal structures, called the Cambridge Structural Database (CSD). From the crystal structures you will learn about our “runaway” molecules and this will help you find where they might be hiding! You can also find this activity on the Festival Zine at page 30.

Get your detective hat ready and let’s find some molecules!

What do you need?

  • A phone with a QR scanner or a computer, tablet or phone so you can link on the web links.
  • Print out of the three "Wanted" posters known as identikits that you can find on this page or if you don't have a print out then a piece of paper to reproduce them.
  • Pen or pencil and if you have them coloured pencils to draw the different coloured atoms.


  1. To start your search of the wanted molecules, ask an adult to click the link or scan a QR code on the "Wanted" poster with a phone. This will bring you to our database, the CSD, where you can find information about the chemical structure.
  2. Now, to fill in the "Wanted" poster, known as an identikit, you need to find the common name of the substance, and then draw the molecule that you can see. In the database we use grey for carbon atoms, red for oxygens and white for hydrogens.
  3. Where can you find the molecule in your home? Use the information from the CSD to help you fill in where the runaway molecule was last seen (write or draw it). Hint: the images below provide some clues. 
  4. Repeat the search for each of the chemicals by clicking on the links or scanning the QR codes filling in the identikit for each.


Once you find all the molecules, what do they have in common? What differences do you observe? Did you notice that there are only three different elements (C, H, O)?

Additional Resources

Image of an example of identikit 


Download your 3 identkits here.

Activities to Discover More About the Crystals

Now that you found the molecules, are you ready to discover each of them?

We hope you enjoy your adventures to discover more about these crystals in our three hands on activities. Before you start each of your adventures you should collect together all your ingredients and materials, read through the health and safety notes and make sure an adult is on hand to help you. You can find all the information you need in our recipe cards and in the Health and Safety section at the bottom of this page

Crystals of Sugar

Have you ever wondered how you can grow your very own sugar crystals at home? In this activity we will make a stick of sugar crystals and we will watch the crystals grow over a few days, while learning about how crystals grow and of course what our sugar sticks taste like!

Thumbnail of the Crystals of Sugar video

Watch the Crystals of Sugar video on YouTube by clicking on the image. Subtitles are available clicking on the icon.


Download the instructions here.

Once you have watched the video, why not try the activity yourselves by downloading our recipe and instruction sheet?

What are you seeing?

This activity is showing an example of crystallisation. At the beginning of the experiment, we dissolved sugar in heated water to make a solution. We added sugar until the sugar no longer dissolved because there was not enough water left to dissolve it. At this point our solution is known as a supersaturated solution and we know our solution is ready. After covering our sticks in sugar to help crystallisation, we then added them to the solution while it cooled down. 

As our solution got colder, the sugar molecules are less happy to stay in solution – this is caused by something called solubility-, they would rather connect with other sugar molecules and are ready to form crystals again. In these conditions, when they meet other sugar molecules in the solution, they start creating a solid, the crystal and our sugar stick starts to grow. You can learn more about what is happening in the activity in our recipe hand-out. 

Chocolate and Lego

Chocolate and Lego: it sounds like the perfect plan for the afternoon. In this activity you will learn more about chocolate and use Lego walls to help us understand why chocolate can lose its snap. In the hands on activity, you will heat and cool chocolate to see how this changes what the chocolate looks, sounds and tastes like, and we will be introduced to something called polymorphism, which will help us understand what is happening to the chocolate, by building Lego walls. 

Thumbnail of What Makes Chocolate Snap video on YouTube

Watch the Chocolate video on YouTube by clicking on the image. Subtitles are available clicking on the icon.


Download the instructions here.

Once you have watched the video why not try the activity yourselves by downloading our recipe and instruction sheet? 

What are you seeing?

The molecules in cocoa butter have at least 6 different ways that they can arrange themselves in a crystal. The different ways the molecules can arrange themselves are known as polymorphs and each polymorph might show very different properties. Polymorph number 5 is the desired form in chocolate bars, as it snaps when you break it, it melts in the mouth, and has a glossy, smooth appearance. When chocolate is melted and cooled down again the chocolate bar turns slightly white (this is called blooming) because another more easily grown polymorph of chocolate has formed. 

To learn more about what is happening and what polymorphism is we can use lego to help explain what is happening - watch our video below. 

Thumbnail of Building Crystals with Lego video

Watch the Lego video on YouTube by clicking on the image. Subtitles are available clicking on the icon.


Make Your Own Snow

When we think of crystals we often think of beautiful snowflakes. In this activity we will learn what snow is made of and watch how we can make a form of snow. We will also discover how snow has different forms, known as polymorphs, just like chocolate. 

Thumbnail of the Make Your Own Snow video

Watch the Make your Own Snow video on YouTube by clicking on the image. Subtitles are available clicking on the icon.


Download the instructions here.

What are you seeing?

In this experiment we add water to sodium polyacrylate to make a substance that looks like snow.  Sodium polyacrylate is a polymer that can absorb more than 100 times its mass in water and its ability to absorb water means you can find it in nappies as well as fake snow!

Sodium polyacrylate is made up of two parts, sodium and polyacrylate.  Polyacrylate is a polymer and polymers are made from joining lots of smaller molecules together in a chain a bit like a smaller version of a chain of rubber bands that you might make a bracelet into. In this experiement our polymer chain is made up of a chemical called acrylate acid joined together in a chain. In the dry powder the positively charged sodium ions are tightly bound within these polyacrylate polymer chains. When water is added the polyacrylate chains prefer to bind with the hydrogen atoms in the water instead allowing sodium to move around and the polymer chains can start to unravel. Usually at this point the mixture forms a gel and starts to suck up water which is why it can be found in nappies. However, in our fake snow we use a different form of sodium polyacrylate that has more links between the chains and this time as we add water the powder swells up still but instead of making a gel it forms tighter dryer flakes that look more like snow. 

Keep Learning

If you have enjoyed your Crystal Adventure then you can keep learning with our Home Learning activites where you will find a battle card game alongside more experiments to explore. 

Health and Safety

The activities on this page are carried out at your own risk and children should be supervised by an adult. Please read these health and safety guidelines to reduce risks.

  • Children should not be left unsupervised with any small items that could be harmful to ingest. 
  • Heating of the sugar solution and heating of the chocolate should be done with an adult to reduce the risk of burns.
    • For the sugar activity heating up the sugar solution and handling the hot sugar solution should be performed by an adult or under the supervision of an adult.
    • For the chocolate melting activity, we have not suggested the use of a flame or a heating element. If, however, you intend to do so to speed up the melting process, please do only when children are under adult supervision.
  • Some people are allergic to the ingredients found in a chocolate bar or sugar so before eating the chocolate or sugar check it is ok to do so with an adult.
  • Any access to the internet from minors should be done under adult supervision.
  • If you print and cut out the indentikits please be aware of potential cuts from scissors or papers.
  • If you have purchased a kit to grow snow or any other crystals then please follow the instructions included in the pack carefully and follow the Health and Safety guidance provided with the kit.
  • If you grow your own snow from a kit you should also make sure you clean the surface where you grow your snow before and after use.