Name_________________________________
Crystallization of an M&M Magma
Directions
1. Determine the proportions of atoms in each mineral. Record these on the data sheet in the
section of the attached table labeled Mineral Compositions.
2.
Wash your hands.
3.
Sort the M&M’s by color. Carefully count the number of M&M’s that represent each
element in the starting Magma composition in the table on Mineral Compositions.
4.
Mix well to form magma chamber and place at one end of the white sheet of paper to form
your magma chamber.
NOTE the relative proportions of atoms (colors of M&M’s) in the chamber.
5.
Begin crystallization of magma by removing appropriate numbers of M&M’s at each
crystallization step. Minerals (M&M’s) that are crystallized in each step are moved to the
other end of the magma chamber.
NOTE the relative proportions of atoms (colors of M&M’s) in the chamber.
6.
After each crystallization step, tally the number of atoms remaining for each of the elements
(colors of M&M’s). Record on the M&M’s Remaining table.
7.
Continue with the next crystallization step (go to step #5).
8.
For each crystallization step, calculate the relative proportions of each element (colors of
M&M) remaining as a percentage of the total remaining after that crystallization step.
Record this information in the Magma Composition table.
9.
Also calculate the proportion of magma remaining (f) as a function of the atoms remaining
as a fraction of the original number of M&M’s. Record this information in the Magma
Composition table.
10. Plot the percentage of each cation in the magma on the appropriate graph on the attached
page.
Reflection
As a group, consider the following questions. Submit your answers (typed), along with your
completed table and graphs.
1.
Compare the types of minerals removed at the beginning of crystallization with those
removed in the middle and end of crystallization.
2.
Apply an igneous rock name to the minerals that were removed in during the 2nd, 6th, and
10th crystallization steps:
Step
Rock Name
2nd
________________________________
6th
________________________________
10th ________________________________
3.
Compare the trends of the different elements throughout crystallization. Refer to your
graphs in your answer.
4.
Magmas are broadly classified by their silica composition according to the following
scheme:
Si%
40
54
70
85
|
Basalt
| Andesite | Rhyolite |
Using the above classification scheme, classify the magma at the following steps:
Step
Rock Name
Initial ________________________________
2nd
________________________________
6th
________________________________
10th ________________________________
5.
Explain how the percentage of silica in magma increases during crystallization despite the
fact that silicate minerals are being removed throughout the crystallization process.
6.
Which aspects of this model magma chamber are realistic? Which are not? Suggest some
ways to make the model more realistic.