Crystal-growing Christmas trees
Equipment needed: per student or pair of students
- Petri Dish or Crystalizing Dish
- Sugar paper or Card from used A4 pad
Chemicals needed: per class
- 180g NaCl dissolved to saturation in 400ml water
- Then add 50ml Fe 2+ 0.1M -0.3M (The most common solutions would be ferrous sulphate or ferrous chloride.
Fresh solutions are best so you do not have too much of the ferrous ions oxidized to ferric ions.)
- Then add 50ml potassium hexacyano-ferrate III (ferri) 0.1M -0.3M
- This gives blue colloid that helps to seed crystal growth.
- Finally added 3 – 15 ml conc ammonia (CORROSIVE)
- This is to accelerate evaporation.
- Continue to stir the mixture some salt will remain undissolved.
- The more ammonia added the finer more feathery the crystal growth.
- Add about 20ml of the reagent made as above to each dish.
- If using sugar paper to make Chinese "Spring" Character cut this into 86mm squares to fit into Petri dish bases otherwise just cut interlocking card triangles and cut branches by snipping out small triangles of card.
- These are left then to stand in the reagent and will develop over 2 to 5 days as shown in photos opposite.
- Below also you will find photos kindly contributed by Noadswood School and Clifton High School.
Safety precautions: see CLEAPSS Hazcards 6, 55B, 79.
See Variation @ CLEAPSS GL131 - Snow scene crystals (Dec 2013)
Artistic variations of trees
--Matthew Edwards 14:45, 9 December 2011 (GMT)--