Microscopes and Crystals - National High Magnetic Field Laboratory

ACTIVITY 15: WHAT VARIABLES AFFECT CRYSTAL GROWTH?
m6: Microscopes and Crystals
Activity 15B
In this activity, students will investigate three variables that may influence the quality of the
crystals:
Variable 1: Temperature
Variable 2: Method of mixing the solution
Variable 3: Amount of solid
By manipulating these variables, students will answer 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 solid added to water in a solution affect crystal growth?
Variable 1:
Students will manipulate the temperature of the liquid used to make their crystals.
1. Provide 2 containers (baby food jars, clear film canisters or other containers).
2. Students label their containers with their names and an H (heated) or a C (not heated). The
same amount of water and copper sulfate or other chemical for each container will be used.
The only difference is the temperature of the water (the variable) used to make each solution.
3. Provide room temperature water for one container and heated water (not boiling) for the
other.
4. Students add 7 g (1 tsp.) of the chemical to 10 ml (2 tsp.) of water in each container. Stir
gently until the chemical dissolves.
5. Students will place two drops of the warm solution on a slide, and two drops of the room
temperature solution on another slide. These should be labeled and then placed where they
will not be disturbed.
6. Students will examine the crystals the next day with hand lenses and with the field
microscopes and record results in their science notebooks.
SCIENCE, OPTICS & YOU GUIDEBOOK
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