Bibi continues the Christmas chemistry series with ‘magic’ crystal growing…
In my quest for the perfect Christmas gift, I’ve come across some pretty cool (if sometimes geeky) stuff. Periodic table shower curtains and wall clocks where the numbers have been switched for element symbols are two examples; however, we have both in the office (the curtains are in the showers in case you were wondering…) and although they are practical, do the job and are chemistry related I thought I should find something a bit more exotic that involves practical chemistry. So the search continued.
Then I discovered the crystal-growing Christmas trees of the Natural History Museum (NHM). They pretty much do what they say on the box: you build a cardboard tree, put it in contact with a solution at the bottom which quickly moves up via capillary action and… hey presto, crystals grow on the branches creating the illusion of fluffy snow over the Christmas tree. The pictures below illustrate the process.
Interestingly, the chemical composition of the solution that forms the crystals is not specified anywhere. No reply was obtained from the manufacturers (see Update below) when I enquired and the box unhelpfully states ‘crystals are all around us and include salt and sugar’ so I decided to search elsewhere. A different website reviewing a similar (more colourful) product explains that the ‘magic solution’ is made up using table salt, water, ammonia and ‘Mrs Stewart’s liquid laundry bluing’. (more…)