Teach the Earth > Hydrogeology > Hydrogeology, Soils, Geochemistry 2013 > Teaching Activities > Isotopes in the Hydrogeologic System

Isotopes in the Hydrogeologic System

Laura Ruhl, University of Arkansas at Little Rock

Author Profile

This activity was selected for the On the Cutting Edge Reviewed Teaching Collection

This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
  • Completeness of the ActivitySheet web page

For more information about the peer review process itself, please see http://serc.carleton.edu/NAGTWorkshops/review.html.

This page first made public: Jun 6, 2013


The students will use activities to understand atomic mass and isotopes and stable isotopic fractionation in the hydrologic system.



Undergraduate course in Hydrogeology (required for environmental geology major)

Skills and concepts that students must have mastered

Students must understand what an isotope is and the difference in stable and radioactive isotopes before they can complete this activity. This is a good activity to accompany a lecture on isotopes.

How the activity is situated in the course

This is an activity that is an enhancement of what is gone over in class. It actually has students perform the calculations associated with isotopic systems.


Content/concepts goals for this activity

Atomic Mass and Isotopic Abundance and Stable Isotopic Fractionation

Higher order thinking skills goals for this activity

The higher order thinking skills involved with this activity are those involving calculations and analysis of their collected data.

Other skills goals for this activity

The students will operate analytical equipment (scale/balance) and work in groups.

Description and Teaching Materials

Included in the materials below are the actual assignment and instructor's notes on materials necessary and set up of the activity. The students will be calculating the atomic mass and stable isotope fractionation decay of isotopes (candy-M&Ms).

Isotopes in the Hydrogeologic System (Microsoft Word 2007 (.docx) 97kB Apr29 13)
Instructor's Notes for activity (Microsoft Word 2007 (.docx) 116kB Apr29 13)

Teaching Notes and Tips


The answers that the students give will indicate whether they understand the activity and therefore met the goals of this assignment.

References and Resources

New TTE Logo Small

Geochemistry resources from across Teach the Earth »

Geochemistry resources from Teach the Earth include:

Specialized collections including

or search

Hydrology/Hydrogeology resources from across Teach the Earth »

Water resources from across Teach the Earth »