Glacier-Related Demonstrations for Chemistry Classrooms

Dean J. Campbell and Kaitlyn N. Walls*

*Bradley University, Peoria, Illinois

The United Nations has declared 2025 as the International Year of Glaciers' Preservation, and March 21, from this year onward, will now be the World Day for Glaciers.¹ Additionally, the American Chemical Society-supported Chemists Celebrate Earth Week is on April 21-27, 2025, and the theme for that is Glaciers: Hot Topic, Cool Chemistry!² These slow-moving sheets of ice are important because they are sources of freshwater and they help to cool the planet. Unfortunately, most of the planet’s glaciers are in retreat, prompting much concern. There are many ways to connect aspects of glaciers to chemistry classrooms, including the use of physical or video demonstrations. Videos describing many of these examples are posted on the YouTube channel Chem Demos. Some of these videos have been organized into categories, along with some discussion-promoting questions, on a Bradley University Chemistry Club Demo Crew website(link is external).³

Structure and Properties of Glaciers, Snow, and Ice

First and foremost, glaciers need ice. The hexagonal structure of water ice, brought about by hydrogen bonding between the water molecules, can be modeled using various media, including Lux Blox toys(link is external).

Lux Blox model of water ice(link is external)⁴ - Lux Blox model of a water molecule with white hydrogen and red oxygen, and several water models combined to form a model of solid water ice. The hexagonal arrangement of water in ice causes snowflakes to have six sides.

Cubic and hexagonal diamond and ice(link is external)⁵ - Comparison of LuxBlox models of cubic and hexagonal diamond and ice. Some ice in glaciers can be melted by elevated pressures deep under the ice.⁶ This can be connected to discussions of phase changes and phase diagrams for water.

Water phase change in ice skating(link is external)⁷ - Ice skating is made possible by solid water converting to a lubricating film of liquid water under the blades of the ice skates. This could be due to pressure from the blades melting the ice, friction of the blades over the ice, or both.

Glaciers can currently be found in many parts of the world, including in \\\western North America.

  

Figure 1 shows the Nisqually Glacier at Mount Rainier in the state of Washington and glaciers near the Alaska/Canada border.

Glaciers are often depicted as being white, which is not surprising in that they are formed from snow. The whiteness of snow and ice that contains trapped air can be explained by the light scattering from the randomly oriented air/ice interfaces. When the ice does not have trapped air, it is more transparent. At the same time, ice is also not completely transparent to all wavelengths of light. It can preferentially absorb red wavelengths over blue wavelengths, so light traveling some distance through ice can give it a bluish appearance. Figure 2 (left) shows how this can be illustrated using frosted and unfrosted glass slides. The roughened surface of frosted glass in contact with air scatters light like the ice crystals in snow. The smooth surface of the unfrosted glass resembles ice in that it does not scatter light in all directions. A stack of ten glass slides absorbs (and scatters) light better than a single slide due to the longer path length of light through the stack. Figure 2 (right) shows bluish-colored ice in an Alaskan glacier.

  

Figure 2. (LEFT) Single vs. stack of ten frosted and unfrosted glass slides, and (RIGHT) small hole in glacier ice showing blue color.

Why is snow white?(link is external)⁸ - Snow appears white because the difference in refractive index between the ice and the air helps to bend and scatter white light. Placing snow in water turns the snow nearly invisible because the refractive indices of solid and liquid water are more similar, and light is bent less. It should also be noted in the glacier images in Figures 1 and 2 that glaciers are NOT completely white, as they can become covered with dust and rocks. Dark-colored materials typically have lower albedo(link is external) and thus absorb sunlight and warm up faster than the ice. This even happens with ice that is not part of glaciers. Figure 3 shows dark-colored leaves on ice that have warmed in the sun and melted down into the ice.

Figure 3. Dark-colored leaves have absorbed sunlight, warmed, and melted down into the white ice.

Ice cores from glaciers and ice caps can be used to obtain historical climate data, both by measuring isotopes in the water itself in the ice and by measuring other species, such as gases in the bubbles in the ice.

Isotope shakers showed the difference in the ability of lightweight and heavyweight beads to move over a barrier wall in a shaken, two-chambered container. This was done to illustrate how isotope distributions in the water in ice can provide information about Earth's temperature history.⁹  These shakers can be used in demonstrations and have also been used in a General Chemistry lab.

 

Figure 4. Bead rattle used to demonstrate how isotope distribution in ice are influenced by temperature.

Image reprinted with permission from Campbell, D. J.; Brewer, E. R.; Martinez, K. A.; Fitzjarrald, T. J. "Using Beads and Divided Containers to Study Kinetic and Equilibrium Isotope Effects in the Laboratory and in the Classroom." J. Chem. Educ., 2017, 94, 1118-1123. Copyright 2017 American Chemical Society. 

Glacial erosion

Glaciers and the rocks they carry, as they bulldoze across the landscape, have considerable erosive power. Many parts of the world that do not currently have glaciers still bear marks from the glaciers of the last Ice Age, for example, in the Midwestern and Eastern United States, far from any ice caps or mountain-based glaciers. Figure 5 shows a large glacial erratic rock (moved by a glacier and eventually left behind as it melted) in Minnesota, scratches and “chatter marks” in a rock formation in Wisconsin, and “potholes” drilled into bedrock by glacier-fed waters swirling stones in circles in Massachusetts.

  

Figure 5. (TOP LEFT) Large glacial erratic rock in Minnesota (TOP RIGHT), scratches and “chatter marks” in a rock formation in Wisconsin, and (BOTTOM) “potholes” drilled into bedrock by glacier-fed waters swirling stones in circles in Massachusetts.

Chatter marks can be created when an object is dragged across a surface, and the dragged object moves up and down as it moves along the surface and leaves repeating marks. Sometimes, chatter marks are made deliberately to create patterns on clay surfaces.¹⁰  In the context of glaciers, rocks can leave chatter marks as they are dragged over large rocky surfaces.

Glacial Chatter Marks and Scratches on Rock in Northern Wisconsin(link is external)¹¹ - Glacial chatter marks and scratches on 1.5 billion-year-old quartz monzonite of the Wolf River batholith in northern Wisconsin.

Rock in glaciers can be ground to produce a fine powder called rock flour. When this fine powder is carried by water, it can make the water appear very cloudy, like the river near Denali National Park in Alaska shown in Figure 6. Sometimes this cloudy water is referred to as glacial milk.

Figure 6. Rock flour turned this river gray near Denali National Park, AK.

Light scattering in and near a glacier-fed creek(link is external)¹² - Light scattering from water droplets from clouds in the sky, water droplets in haze in the cool air above the creek, and rock particles (likely ground up by glaciers) in the water in the creek. Correction to the video: The light scattering exhibited is more likely Mie scattering from particles bigger than the wavelengths of visible light than Tyndall scattering from particles about the same size as the wavelengths of visible light, as the scattered light is not noticeably bluish.

All of the disintegrated rock being transported away from melting glaciers raises questions about what sorts of elements are being transported in the water. The movement of elements from glaciers into the oceans, both modern¹³ and ancient,¹⁴ are being studied. One might expect that finely divided rock flour would have an abundance of surface area to enable faster dissolution of elements into water. This can be connected to all sorts of other demonstrations where finely divided substances can dissolve or react more quickly than bulk substances. 

Crushed and uncrushed antacid tablets vs. acid(link is external)¹⁵ - Time lapse of three uncrushed calcium carbonate-based antacid tablets vs. three crushed calcium carbonate-based antacid tablets added to hydrochloric acid solutions containing universal indicator. The crushed antacid tablets, with their greater surface area, raise the pH of the acid solution more quickly than the uncrushed tablets. However, the uncrushed antacid tablets appear to eventually catch up.

Space and glaciers

Earth’s glaciers are observed from space platforms such as the European Space Agency Sentinel 2 and the National Aeronautics and Space Administration Landsat 8 satellites.^16,17 These satellites can have different sensors that operate at varying spectral regions (e.g., infrared, visible, etc.) to measure properties such as speed of glacial movement, ice thickness, and more!¹⁶ Through this monitoring, scientists can determine the effects of climate change at Earth’s poles and predict how rising temperatures will continue to affect glaciers.¹⁷ For example, seasonal movement patterns in different regions can help climate scientists study rifts in ice sheets. These rifts can cause icebergs to break off and contribute to rising sea levels, as seen on the Larsen C Shelf in 2017.¹⁸

Our neighboring planet, Mars, has a cold, dry, rocky, and dusty surface and a thin atmosphere that does not protect the planet from radiation, making it seemingly impossible for life to survive.¹⁹ Interestingly, however, there are sources of water on Mars: glaciers. Mars, like Earth, has ice caps at its poles, which contain water and carbon dioxide.²⁰ It also might have rock-covered glaciers containing water ice at mid-latitudes, similar to glaciers in Antarctica.²⁰ The glaciers on Mars can offer a wealth of information about Mars’s climate history.²¹ Similar to the process of drilling ice cores on Earth, astronauts or robots could drill into Martian glaciers to tap into the history of its climate.

Big dry ice pile in a parking lot(link is external)²² - Visit to a dry ice facility near an ethanol plant in Pekin, IL. The carbon dioxide in the dry ice pile was likely a byproduct of ethanol production. Deposits of dry ice have been found on Mars, where carbon dioxide makes up the majority of the atmosphere.

By studying glaciers, whether on our home planet or beyond, scientists can better understand a planet’s climate.

A final thought…

Visiting the websites described in the references can provide more details about the features of glaciers. Please take the time to visit a glacier, even if you do not live near one. Find out how the glacier has changed over time, maybe by looking at topographic maps or aerial photographs. Many, but not all, of the world’s glaciers are in retreat (that is, they are melting faster than they can advance – a glacier does not actually flow backward). A visit to the Nisqually Glacier on Mt. Rainier in Washington (Figure 1) and learning how that glacier has retreated over the decades left a deep impression on one of the authors. Please visit glaciers while you still can.

Safety

I have worked to maximize safety, but each demonstration and prop comes with its own particular set of safety considerations. If physical classroom examples are to be done in person, then instructors must identify and respond to potential hazards, personal protective equipment, and disposal issues associated with these examples.

Acknowledgements This work was supported by Bradley University and the Mund-Lagowski Department of Chemistry and Biochemistry with additional support from the Illinois Heartland Section of the American Chemical Society. The material contained in this document is based upon work supported by a National Aeronautics and Space Administration (NASA) grant or cooperative agreement. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author and do not necessarily reflect the views of NASA. This work was supported through a NASA grant awarded to the Illinois/NASA Space Grant Consortium. Special thanks to Audrey Stoewer for developing the video website.

References

1.   UNESCO and World Meteorological Organization. 2025 International Year of Glaciers’ Preservation: Background. https://www.un-glaciers.org/en/background(link is external) (accessed April, 2025).

2.   American Chemical Society. Chemists Celebrate Earth Week. https://www.acs.org/education/ccew.html(link is external) (accessed April, 2025).

3.   Bradley University Chemistry Club. Demo Videos. https://sites.google.com/mail.bradley.edu/bradleychemdemos/demo-videos(link is external) (accessed April, 2025).

4.   Campbell, D. J. Chem Demos YouTube Channel: Lux Blox model of water ice. https://youtu.be/EB0LexwmOaI(link is external) (accessed April, 2025).

5.   Campbell, D. J. Chem Demos YouTube Channel: Cubic and hexagonal diamond and ice. https://www.youtube.com/watch?v=LkvZgx_bC3k(link is external) (accessed April, 2025).

6.   Schohn, C. M.; Iverson, N. R.; Zoet, L. K.; Fowler, J. R.; Morgan-Witts, N. Linear-viscous flow of temperate ice. Science, 2025, 387, 182-185.

7.   Campbell, D. J. Chem Demos YouTube Channel: Water phase change in ice skating. https://youtu.be/Vc8gb6IhdLs(link is external) (accessed April, 2025).

8.  Campbell, D. J. Chem Demos YouTube Channel: Why is snow white? https://youtu.be/Hq8ew4dmULQ(link is external) (accessed April, 2025).

9.  Campbell, D. J.; Brewer, E. R.; Martinez, K. A.; Fitzjarrald, T. J. "Using Beads and Divided Containers to Study Kinetic and Equilibrium Isotope Effects in the Laboratory and in the Classroom." J. Chem. Educ., 2017, 94, 1118-1123.

10.   Reed, B. Ceramic Arts Network: Chattering Pottery: Turning a Fault into a Fantastic Surface. https://ceramicartsnetwork.org/daily/article/Chattering-Pottery-Turning-...(link is external) (accessed April, 2025).

11.   Campbell, D. J. Chem Demos YouTube Channel: Glacial chatter marks and scratches on rock in northern Wisconsin. https://youtu.be/WQ_5ex2wW9Y(link is external) (accessed April, 2025).

12.   Campbell, D. J. Chem Demos YouTube Channel: Light scattering in and near a glacier-fed creek. https://youtu.be/6mj-Ctlo0v8(link is external) (accessed April, 2025).

13.   Kim, I.; Kim, G.; Choy, E.G. The significant inputs of trace elements and rare earth elements

      from melting glaciers in Antarctic coastal waters. Polar Research, 2015, 34, 24289.

14.   Kirkland, C. L.; Strachan, R. A.; Archibald, D. B.; Murphy, J.B. The Neoproterozoic glacial broom. Geology, February 25, 2025.

15.   Campbell, D. J. Chem Demos YouTube Channel: Crushed and uncrushed antacid tablets vs acid (time-lapse). https://www.youtube.com/shorts/stTMx1fxbBg(link is external) (accessed April, 2025).

16.   GIS and Earth Observation University. Glacier Mapping using Earth Observation Satellites. https://www.geo.university/courses/glacier-mapping-using-earth-observati...(link is external) (accessed April, 2025).

17.   Tollefson, J. Satellite system tracks glaciers' flow in real time. Nature, 2016, doi:10.1038/nature.2016.21165.

18.   Larour, E.; Rignot, E.; Poinelli, M.; Scheuchl, B. Physical Processes Controlling the Rifting of Larsen c Ice Shelf, Antarctica, prior to the Calving of Iceberg A68. Proceedings of the National Academy of Sciences, 2021, 118 (40). https://doi.org/10.1073/pnas.2105080118(link is external).

19.   NASA STEM Team. What Is Mars? (Grades 5-8). https://www.nasa.gov/learning-resources/for-kids-and-students/what-is-ma...(link is external) (accessed April, 2025).

20.   Butcher, F. AntarcticGlaciers.org. Types of Glaciers on Mars. https://www.antarcticglaciers.org/glacial-geology/glaciers-on-other-plan...(link is external) (accessed April, 2025).

21.   Jet Propulsion Laboratory. NASA. NASA Is Locating Ice on Mars With This New Map. https://www.nasa.gov/solar-system/planets/mars/nasa-is-locating-ice-on-m...(link is external) (accessed April, 2025).

22.   Campbell, D. J. Chem Demos YouTube Channel: Big dry ice pile in a parking lot. https://youtu.be/dJ5v9Osb5xk(link is external) (accessed April, 2025).