Student-Built Model of Bacterial Cell Shapes

By Laura Hospitál on Feb 18, 2015

The three basic shapes of bacteria are bacillus (rod-shaped), coccus (spherical-shaped), and spirillum (spiral-shaped).

This simple model allows students to build the three shapes of bacteria in a short period of time.

Picture of spiral shaped bacteria.








Picture of rod-shaped bacteria

Picture of spherical-shaped bacteria


Prepare a chenille stem (formerly pipe cleaner) and a small bowl of play dough for each student.


  • 8 oz white play dough per student
  • 1 white Chenille Stems (formerly pipe cleaners) per student
  • 1 unsharpened pencil per student


After instruction on the 3 cell shapes of bacteria, prepare play dough and a chenille stem for each student.

Before the students begin, review the shapes by asking the students to recall the 3 shapes.  Also, ask students how many cells a bacterium has.  Remind them that all bacteria are one-celled organisms. 

  1. Review the shapes.
  2. Beginning with the baccillus and coccus bacteria, have students build these types using play dough.  Assist if necessary.
  3. Ask students how they might use a chenille stem and a pencil to build a spiral-shaped bacteria cell.  Guide them, if necessary, to twist the chenille stem around the pencil.
  4. Either complete review questions or defintions related to the 3 shapes of bacteria after the activity to solidify the concepts in their minds. 


  • Different colors of play dough could be used if more visible to students with low vision.

NGSS Standards:

Middle School: Structure, Function, and Information Processing

LS1.A: Structure and Function:  All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular). (MS-LS1-1)

Collage of student-built model of bacterial cell shapes


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