Rates and Time > Using Analogies to Teach about Time

Using Analogies to Teach about Time

This web page is based on a document produced by Iylse Resnick, Noah Fay, Sarah Gerken, Leah May Ver, and Karen Viskupic at the 2012 Workshop on Teaching About Time.

Jump down to Common analogies for time | Assessing student understanding | References

Guiding Principles for Teaching with Analogies

Analogy refers to relating two different concepts based on shared features. The two concepts are referred to as the base and the target. The base concept is the one that is already familiar. The target concept is the one we want to learn about. Used well, analogies can be excellent teaching tools; used poorly, they may be of little use and can even introduce misconceptions. Based on research on the use of analogies in teaching (see references) we recommend the following guidelines for the use of analogies in teaching about time:

Common Analogies for Time

There are many common analogies used for representing the Geologic Timescale and the expanse of time. Our goal here is to discuss a few of these analogies in the context of the guiding principles listed above. Please note that the strengths and weaknesses described here may or may not be relevant to the specific way you use the analogy in your class. Moveover, many of the weaknesses described here can be addressed by pointing them out to students (where the target concept differs from the base concept) and by using progressive alignment (where the scales of the base and target concepts are vastly different).

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Paul Heller's 24 hour representation of geologic time. Download Geologic Time 24 hour clock (Quicktime MP4 Video 1.6MB) Details

Analogies that map time onto other magnitudes of time

Examples: day, year, clapping (once/second represents one year: Clary and Wandersee, 2009)


Potential Weaknesses

Analogies that map time onto distance

Examples: Mapping geologic time onto a piece of string, a length of clothesline, a meter stick, a roll of toilet paper, a segment of sidewalk, a length of hallway, a trip across the country


Potential Weaknesses

Analogies that map time onto spaces or volumes

Examples: Mapping geologic time onto the Eiffel Tower, the Washington Monument, a football field, a swimming pool


Potential Weaknesses

Assessing Student Understanding of Analogies

Assessing whether students understand the analogies you are using is critically important: if they don't understand the analogy, they won't understand the target concept. Assessment can be built into the analogy activity, and can focus on parts of the analogy (or the intermediate steps in progressive alignment) that you expect to be challenging. Possible assessment could include:

To choose an assessment activity or activities, consider what you want to achieve:

By carefully considering your (and your students') needs, you can select appropriate assessment methods to meet those needs. For example, if you want your or your students to get immediate feedback on how well they understand the analogy, you could use ConcepTest or Classroom Response System (clicker) questions, small group discussions, or written student reflections the day you introduce the analogy. If you want to know how well students understand the target concept, you could ask them to develop their own analogy for it. If you want to know how well they retain their understanding, an exam question later in the term may be more appropriate.


Clary and Wandersee (2009). How old? Tested and trouble-free ways to convey geologic time. Science Scope, Dec. 2009, p. 62-66.

Jee, Uttal, Gentner, Manduca, Shipley, Sageman, Ormand, & Tikoff (2010). Analogical thinking in geoscience education. Journal of Geoscience Education, 58 (1), 2-13.

Kotovsky and Gentner (1996). Comparison and categorization in the development of relational similarity. Child Development, 67, 2797-2822.

Parker, J. D. (2011). Using Google Earth to Teach the Magnitude of Deep Time. Journal of College Science Teaching, 40 (5), 23-27.

Thompson and Opfer (2010). How 15 hundred is like 15 cherries: Effect of progressive alignment on representational changes in numerical cognition. Child Development, 81 (6), 1768-1786.

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