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Not so Green Up Close: a Peek at a dyed Chicago River Sample

Dean Campbell | Sat, 05/17/2025 - 22:36

Light absorbance and fluorescence were studied for a sample of the Chicago River that had been dyed green for St. Patrick’s Day. The sample had weak green fluorescence, showing that the intense green appearance of the river was in part due to the long path length of light through the water. The ability of the green color to partition into 1-octanol was also explored.

Demonstrating the Glass Transition of Polylactic Acid with a Rattle

Dean Campbell | Wed, 03/27/2024 - 20:42

Polylactic acid (PLA) exhibits a glass transition from hard and brittle to soft and rubbery when immersed in boiling water. PLA-based structures containing a small metal object can be used as rattles when they are shaken. The sound of the rattles change when they are heated above or cooled below their glass transition, enabling them to be used as demonstrations.

Chemical Activities Involving Reversible Thermochromic Pigments

Dean Campbell | Wed, 08/16/2023 - 07:17

The color of a thermochromic system depends on its temperature. The colors of leuco dye-based systems can also be influenced by adding acids or bases to the thermochromic reactions. These can be used to create colorful demonstrations of acid-base chemistry. Thermochromism found in color changing cups can also be used to visualize heat flow, and therefore thermodynamic principles, associated with stretching and contracting elastomers.

Managing Student Collaboration with Kristen Drury & Stephanie O'Brien

Deanna Cullen | Mon, 04/26/2021 - 07:08

POGIL activities can be used to engage students in chemistry lessons through the use of student teams, effective models, and tiered questioning. Kristen Drury and Stephanie O'Brien presented in a ChemEd X Talk on April 21, 2021 and provided teachers with guidance on fostering student buy-in, student role formation, and POGIL implementation. Additionally, information was shared on how to assess students' participation in POGIL activities holistically and through individual examination of process skills such as communication, teamwork, and problem solving. You can watch the edited recording of their Talk here.

Cognitive Load and Active Learning

Clarissa Sorens... | Tue, 11/05/2019 - 10:20

A couple of days ago on Twitter, the ever-lasting debate between lecture and active learning reignited due to some talks at an Educational Research Conference held in Dublin. These talks stated direct guidance (which includes lecture) was superior in terms of student learning due its reduction of students’ cognitive load. The main citation used for this argument was an article by Kirschner, Sweller, and Clark published in 2006. So, let’s dive into what this article says.