My Notes
Categories
Topics Covered
Subdiscipline
Description
This is a really fun Challenge where student use two colors of marbles to simulate close packing. It culminates in them creating the face-centered cube "hidden" in hexagonal close packing.
| Attachment | Size |
|---|---|
| 4 close packing.doc | 73 KB |
Equipment needs
Boxes (typically from disposable pipettes), clear and blue marbles about 12 mm diameter, 20 mm water bath balls (VWR), small ruler.
Implementation Notes
see end of file
Time Required
1 hour
Evaluation
Evaluation Results
This is always enjoyable and moderately challenging. Some groups will need some help along the way.
Creative Commons License
Attribution, Non-Commercial, Share Alike CC BY-NC-SA
We did this activity at the 2019 VIPEr Fellow Cohort meeting at the University of Michigan-Dearborn. We modified the activity by purchasing a variety of colored marbles and then splitting them into six sets with only two colors (rather than the clear + blue marbles in the LO). The Fellows really seemed to like it and were brainstorming ways to improve the activity and even expand it. Below are some of the suggested revisions, adaptations, and expansions. I’ve also included some pictures from the groups to show what it can look like.
Revisions & Adaptations:
-Use a pen, ruler, phone, or other straight edge to create a boundary for the marbles within the box to help keep the structure
-The boxes we had had a felt piece on the bottom of the box (think Jewelry boxes). The felt seemed to help give some friction to keep the marbles from moving around too much
-Some Fellows brainstormed using a layer or sand or playdough at the bottom of the box to help keep the bottom layer from rolling around (particularly when adding additional layers). One Fellow even suggested making a 3D printed board with wells for each marble on the first layer (one board for cubic and another for hexagonal packing).
-Magnetic marbles were suggested as way to allow the students to rotate the packed cubes to see different angles (and minimize rolling around when building structures). While you can buy a magnetic lattice of NaCl, generic magnetic marbles may be more cost effective.
-Using larger sized marbles will help students see the empty spaces within the structures
-Making sure the boxes used are approximately the same length & width of the suggested builds may help with keeping the structure. One Fellow suggested buying clear Tupperware containers (small square/rectangles) may be good because then students who see through the container while giving structure to the different builds
-Alternating layers of clear and colored marbles might help students see the different layers, particularly with the clear marbles so students can ‘see’ through the whole structure.
Expansions:
-A way that was suggested to expand the activity was to buy two different sizes of marbles to model how atomic radius relates to packing.
-The activity provides a good introduction to discussing limitations of models and why scientists develop different models when needed to explain phenomena.
Pictures: