Originally a GalaxyGoo project, I'm now hosting the project here.
Building Models Cells with Clay
--updates and images coming soon--
In the Clay Cell activity, students build 3-d models of cells, organelle by organelle. Once the clay dries, the cells are sliced and the resulting cross-sections are examined.
This activity was developed with Crayola's Model Magic. It works well for mixing colors and dries into a light, foam-like material.
Note: Model Magic dries out quickly and cannot be re-used by adding water. Open only what you will use immediately. If you are going to mix colors ahead of time, be sure to keep it in air-tight containers.
Choose which color to use for each organelle. The organelle models can be as detailed or general as you have time for.
Wrap a thin layer of "cytoplasm" around each organelle. The cytoplasm color should not be used in any of the organelles.
Assemble your cell from the organelles, with the nucleus in the center, the endoplasmic reticulum around the nucleus, and so on. If the clay is too dry to stick together, use a thin layer of "cytoplasm" between each organelle.
Instead of wrapping individual free-floating ribosomes, try adding them to the cell and covering with a thin layer of "cytoplasm".
*Be sure to remind your students that real cytoplasm is a jelly-like substance that the organelles "float" in, and that we are wrapping cytoplasm this way for the sake of constructing our model.
The last step in building the cell, is to wrap the cell membrane around the organelles.
If you are building a plant cell, you will need an additional step of adding the cell wall.
If you build your organelles and assemble the model in one session, it could take a week or more for the model to dry enough to get clean sections.
If you slice while still wet, you can use dental floss or similar string. The resulting sections are a little smeared, but you can look at them immediately. You might want to do this as an example during class.
Once dry, the clay is too tough to be sliced with string, but a sharp knife will work fine. The drier the clay, and the more carefully you slice, the cleaner the sections will be.
If you have time, you can have the students draw cell diagrams from their collected cross-sections. How many sections do they need to see examples of all the organelles in a cell? How many models does the class need to make to get representations of all the organelles?
The Cell Project began as part of Frances Segal's internship at GalaxyGoo, and as part of her Master's thesis. Ms Segal collaborated with middle-school teachers and GalaxyGoo developers to develop a learning tool focused on the life sciences for 7th grade students.
Since then, the project has grown and developed into an expanding set of activities focused on learning about the basic unit of biology: the cell.
In February of 2007, GalaxyGoo took the Clay Cell activity to the Family Science Days (a family-focused event during the 2007 national meeting of AAAS).
GalaxyGoo took the Clay Cell Acticity to the Maker Faire in 2008. Invitation to teachers: Coming Soon!