Thursday, 15 December 2011

Make your own real crystal snowflake

Here's an experiment to try now it's getting to that time of year when we may or may not have some snow...



First you will need:
  • a jam jar
  • a pipe cleaner
  • salt, sugar or borax
  • boiling water
  • some cotton
  • a pencil, or something of a similar shape.

First use the pipe cleaner to make a 6 pointed shape a bit like this:



Then tie cotton to it like this, you need enough of it to tie to this pencil so it can hang freely in the jam jar later.




Tie the end to a pencil and then leave for a moment while you do the rest. 
 
Boil the kettle and fill the jam jar to the top with boiling water. 
 
Add your salt, sugar or borax to the water bit by bit waiting for it to dissolve, then add some more, repeat this until no more with dissolve.



Gently lower the snowflake shape into the water hanging it using the pencil.  Like this:



Now all you need to do is wait and watch the crystals form.  If using salt and sugar it's best to wait at least 24 hours.  After a good few days it will be looking pretty good though.
 
You can also try this with sugar, table salt (sodium Chloride) or Epsom Salts (magnesium Sulphate).  If you fancy having a blue one you could try copper sulphate!

Have fun with your Christmas Science Project!
 
How it works...
Crystallisation is a technique used by scientists, it's a form of separation.  It is the process of separating a liquid and a solid.
 
In this experiment we are separating the water from the borax.
 
When the solution is warm it will stay a solution but as it begins to cool the solid and liquid will separate, liquid evaporates and crystals begin to form.
 
The size of the crystals depend on how quickly the solution cools down.  The fast the cooling process the smaller the crystals (but there will be more of them) the slower the cooling process the bigger the crystals (but there will be fewer of them).

2 comments:

  1. Looks good - We tried similar with bicarb last year must have another go. Thanks for the reminder

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  2. Oooh... Bicarb another good one thank you for that xx

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