Try growing some crystals and geodes
You’ll need
- Access to water
- Kitchen scales
- Spoons
- Food colouring
- Scissors
- Heat-resistant jugs
- Magnifying glass (optional)
- Specific equipment for experiments (see instructions)
Before you begin
- Use the safety checklist to help you plan and risk assess your activity. There's also more guidance to help you carry out your risk assessment, including examples. Don’t forget to make sure all young people and adults involved in the activity know how to take part safely.
- Make sure you’ll have enough adult helpers. You may need some parents and carers to help if you’re short on helpers.
Planning this activity
- This activity needs to be run across more than one session, in order to allow time for the crystals to grow. This should give everyone time to think about their experiment, look forward to seeing how it turned out, and which methods worked best.
- You could also run this activity as one of two or more bases. If you’re running several experiments, make sure you have enough adult supervision for each one and that all the equipment you need is to hand and ready.
- There are three experiments in this activity. Groups could choose which one they’d like to do at the start, and do another if there’s time.
Run the activity
- If you’re not running this activity as a base, everyone should get into small groups to do the experiments. Check out the three different options below!
- Once you’ve completed your experiment(s), gather everyone together to talk about the science involved in making crystals and geodes. See if anyone knows anything already about how crystals are formed and what happens to sugar or salt that dissolves in water.
- See if anyone can work out why the water needed to be heated first, and why cold water wouldn’t work in the same way.
- See if anyone can work out why a penny, an eggshell and a pipe-cleaner were used, and which method will grow the biggest crystals.
- Pour 100ml into a heat-resistant jug. The water should be as hot as possible, you could boil a kettle but be careful and make sure that an adult is around to supervise.
- Weigh out 100g of Epsom salt and add it to the hot water.
- With a spoon, stir the salt into the water for a few minutes until it dissolves.
- Add a drop of food colouring to the water.
- Check the salt has dissolved. When it has, pour some of the liquid from the jug onto a white plate on a tray. Place the tray on a windowsill or somewhere out of the way.
- Place a penny in the middle of the white plate, in the liquid.
- After three days, or at the next session, check back and you should see long, thin crystals on the plate. If you can, check them out under a magnifying glass.
You will need
- Epsom salt
- Caster sugar
- White plates
- Pennies
- Trays
- Take an egg and make holes in either end using a pin.
- Blow into one end of the egg and empty the egg white and yolk out into a bowl through the other end. Then, break the shell in half. Do this in advance if you’re short on time or if no-one wants to get egg on their face! (Running this experiment alongside a pancake-making base will allow you to use up these egg whites and yolks.)
- With a paintbrush, paint glue onto the inside of the shell, sprinkle with alum powder and leave to dry for a short time.
- In the meantime, fill a beaker with hot water and add alum powder until no more will dissolve. Add some drops of food colouring and stir.
- Once the glue is dry, drop the eggshell into the beaker of water and leave it somewhere out of the way to crystallise.
You will need
- Alum powder
- Eggs
- Drawing pins
- PVA glue
- Paintbrushes
- Beakers or mugs
- Shape a pipe-cleaner into a familiar shape, like someone’s initials or an animal.
- Tie the pipe-cleaner to a length of fishing line and tie the line onto the middle of a wooden skewer.
- Fill a beaker with hot water and dissolve as much alum powder or salt as possible, in small amounts, before adding some drops of food colouring.
- Dangle the pipe-cleaner into the beaker solution and rest the skewer across the top, so that it doesn’t fall in. Try and get the pipe-cleaner to float in the centre of the beaker, without touching the sides or bottom.
- Leave your solution somewhere safe and out of the way until the next session.
You will need
- Alum powder or salt
- Pipe-cleaners
- Fishing line
- Wooden skewers
- Beakers or mugs
Reflection
Crystallisation, like most scientific experiments, can be difficult to predict. Whose experiments turned out exactly as they thought? Was anyone’s really different?
All you need to start crystal growth is one tiny molecule, like a grain or seed, for the crystals to form around. This shows how something impressive can be grown from something small. Can anyone think of any other examples of this? These experiments are a great example of how combining and working together can help us excel!
Safety
All activities must be safely managed. You must complete a thorough risk assessment and take appropriate steps to reduce risk. Use the safety checklist to help you plan and risk assess your activity. Always get approval for the activity, and have suitable supervision and an InTouch process.
- Science
Supervise young people, and only do science activities that are advised and age appropriate for your section. Test activities first, to make sure you’re confident you can lead them safely. Use protective clothing where necessary.
- Food
Remember to check for allergies, eating problems, fasting or dietary requirements and adjust the recipe as needed. Make sure you’ve suitable areas for storing and preparing food and avoid cross contamination of different foods. Take a look at our guidance on food safety and hygiene.
- Scissors
Supervise young people appropriately when they’re using scissors. Store all sharp objects securely, out of the reach of young people.
- Sharp objects
Teach young people how to use sharp objects safely. Supervise them appropriately throughout. Store all sharp objects securely, out of the reach of young people.
- Glue and solvents
Always supervise young people appropriately when they’re using glue and solvent products. Make sure there’s plenty of ventilation. Be aware of any medical conditions that could be affected by glue or solvent use and make adjustments as needed.
- Chemicals
This task involves the use of potentially harmful fluids or chemicals. Make sure you follow all relevant safety guidance. Make sure you dispose of them appropriately too, in line with safety guidance.
You have loads of options for changing the experiments: different salts or caster sugar, colours, amount of solid dissolved, the growing technique (plate and penny, egg or pipe cleaner), and how fast or slow you cool the solutions. Have a quick think about this before the session, so that you can prepare enough materials in advance to challenge the group.
- If the crystals can’t be left on a windowsill they could be left on a table out of the way. If they can’t be left at the meeting place for long enough for the crystals to grow, everyone could take their solution home in a bottle and follow the steps at home, or you could complete this activity on camp!
- Make sure everyone has the assistance they need to complete the experiments in this activity. Bear this in mind when splitting off into groups.
All Scout activities should be inclusive and accessible.
Why not explore how this science is used in everyday life. Crystals appear everywhere – how many can everyone name? To get started think about snowflakes, minerals (like geodes), salt/sugar, ice, honey turning solid, even chocolate is crystallised cocoa butter! There are lots of other examples to investigate.
Young people had the choice of which experiment to do and which variations to try to change the outcome.