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Supported by Rolls-Royce

Crystal creations

Shape some new wonders of the natural world in your meeting place, by creating some sparkling crystals and geodes.

You will 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

  • 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

  1. 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!
  2. 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.
  1. 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.
  1. 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.

You will need

  • Epsom salt
  • Caster sugar
  • White plates
  • Pennies
  • Trays

You will need

  • Alum powder
  • Eggs
  • Drawing pins
  • PVA glue
  • Paintbrushes
  • Beakers or mugs

You will need

  • Alum powder or salt
  • Pipe-cleaners
  • Fishing line
  • Wooden skewers
  • Beakers or mugs


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!


All activities must be safely managed. Use the safety checklist to help you plan and risk assess your activity. Do a risk assessment and take appropriate steps to reduce risk. Always get approval for the activity and have suitable supervision and an InTouch process.


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.


Check for allergies before you begin and read the guidance on food safety. Make sure you have suitable areas for storing and preparing food and avoid cross contamination of different foods.


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

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 which could be affected by glue or solvent use and make adjustments as needed.


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.