Special
Project: Growing
Crystals
Earth & Planetary Science 2: Gems and Gem Materials
The lab will run over the last 5 weeks of semester. You are encouraged to start thinking about this earlier (and organizing materials) but you will not have access to the microscope and related resources to characterize your crystals until the last half of the semester.
Gems, which we study in EPS2, are frequently made of crystals. Because EPS2 is a science course, we’d like you to experience a little lab science as well. So, over the next 5 weeks, you’re going to grow a crystal and make observations of it. The purpose of this project is to help you get practice in using your own observations to come to conclusions about the world around you, and then to explain the results in a short report. Be sure to hand in your final report, written in your own words, and showing your own, original observations.
There are several websites which are excellent references for how to grow crystals at home, listed in the bibliography below. Additional books are on reserve at the Earth & Planetary Science Library in McCone Hall. There are many more books on crystal-growing techniques than are listed. Feel free to use them, but please cite them in your summary report. (Especially if you liked them.)
You may choose from a variety of
substances: salt, sugar,
baking soda, Epsom
salts.
Others may be available on
request.
If possible, you should grow the crystals at two temperatures (refridgerator at home, if possble and in the fume hood in 369 McCone) and compare the results. Note that you should not put anything other than the most harmless compounds in your home refridgerator, ask us if you are uncertain!
When you have a crystal, additional lab resources may be available to closely examine the surface of your crystal or the structure.
To be turned in:
A lab-book: this should be a record made as you work, recording exactly what you did while growing the crystal, and what problems you ran into. For this project, you should record things which you think could influence crystal growth, e.g. room temperature, ambient light (sunny? dark?) Include sketches of your experimental setup and sample (pictures are also OK, if you don’t consider yourself a good artist.)
N.b.: Think carefully about what kind of data you want to record and how best to record it. An illegible or poorly planned lab-book is almost worse than not keeping one at all!
A short summary report (1-2pages): about your crystal—this should include a summary of what mixture and method you used to grow it, the composition, shape, crystal system, cleavage, and so forth. Include an estimate of the growth rate, from both observation and measurement.
Option: You may turn these in as a webpage, if you prefer.
Bibliography:
http://rockhoundingar.com/pebblepups/growcryst.html
http://www.sciencenet.org.uk/publications/crystal.html
http://www.kerala.com/science/project1_page1.htm
http://www.seawhy.com/xlrxlgen.html
Crystals and crystal growing, by Alan Holden and Phyllis Singer. Chemistry QD921 .H64; Earth Sci QD921 .H64 (On reserve in the library.)