Microscopes and Crystals - National High Magnetic Field Laboratory

ACTIVITY 15: WHAT VARIABLES AFFECT CRYSTAL GROWTH?
m6: Microscopes and Crystals
A CT
CTIVITY
What Variables Affect Crystal Growth?
Activity 15B
Almost every solid that occurs in nature is made up
of crystals. The minerals found on earth have
differently shaped crystals. Salt looks like rough sand
to the unaided eye, however when looked at using a
hand lens or a microscope, it is actually made up of
small cube-shaped crystals. Many crystals are
transparent, others are colored. Some crystals, like salt,
are very small, while others are large enough to be seen
without a hand lens or a microscope. What causes crystals to be so different from
one another?
In this activity you and your group are going to investigate variables that affect
crystal growth. Before beginning this activity, think about how you made crystals
in Activity 14.
You will be making crystals three different ways. Each time you will be changing
one thing (this is called a variable) when you make your crystals. The three
different variables you will be testing are: temperature, method of mixing the
solution, and amount of solid. In doing this, you will try to anwer the following
questions:
1. Does the temperature of the water in a solution affect crystal growth?
2. Does stirring or shaking a solution affect crystal growth?
3. Does the amount of chemical added to the water affect crystal growth?
SCIENCE, OPTICS & YOU GUIDEBOOK
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