As cases due to COVID-19 continue to rise, many schools remain locked in virtual learning formats. Consequently, meaningful laboratory work remains a challenge for many. This semester, I started creating my own virtual chemistry laboratory activities for my high school chemistry course.
In this activity, students learn about solubility and concentration. In section 1, students answer questions from a video that explains the dissolving process and how to calculate the molarity of a solution. In section 2, students answer questions from a video that explains supersaturation and how to make rock candy from a supersaturated solution of sugar and water. Then, they use a PhET simulation to explore factors that affect the concentration of a solution. Finally, in section 3, instructions are included so that students can try making their own rock candy at home.
This activity can be completed in one 50 minute class period. The extension "at home" section would require about 60 more minutes.
Section 1 and 2 only require YouTube videos and the PhET simulation, "Concentration", Section 3 (at-home investigation) requires 2 cups of tap water, 6 cups of granulated sugar, wooden skewers, clothes pins, large glass mason jar, pot for boiling water.
Section 1 - Dissolving and Concentration
The activity begins with a short video (video 1) that introduces the dissolving process. This video explains how certain substances dissolve in water, defining terms like solute, solvent, and solution. Additionally, students learn and practice calculating the molar concentration of a solution.
How does dissolving work? (& molarity)
Video 1: How does dissolving work? (link is external) on the Science Classroom (link is external) YouTube Channel (Published 10/20/2020)
Section 2 - Factors that Affect Concentration
Once again, students watch a short video (video 2) that introduces factors that affect concentration. Specifically, this video describes the relationship between the temperature of a solution and the solubility of a solid. The video also demonstrates how this knowledge can make rock candy from a supersaturated sugar and water solution. After the video, students use the PhET simulation, Concentration (PhET Interactive Simulations at University of Colorado Boulder, under the CC-BY 4.0 license, to explore other factors that affect concentration.
Supersaturated Sugar Solution!
Video 2: Supersaturated Sugar Solution (link is external) on The Science Classroom (link is external) YouTube Channel (Published 10/23/2020).
Section 3 - Try it at Home
The final, optional section of the lab provides instructions for students to make their own rock candy (image 1). The procedure is simple enough that they can perform it in their kitchen at home.
Image 1: Rock candy produced according to the instruction in section 3.
Students work through the Virtual Lab Activity: Solubility and Concentration assignment document (found in the Supporting Information) as described below (image 2). log into your ChemEd X account for access. The document includes all of the required links to videos and PhET simulations.
Image 2: Example of questions in the student document (available in the Supporting Information).
The student document, including questions, can be found in the Supporting Information below. Log into your ChemEd X account for access.
No teacher preparation is required unless completing the "at home" portion as a demonstration for students.
YouTube Channel: The Science Classroom. & PhET Simulations
Safety
General Safety
General Safety
For Laboratory Work: Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016).
For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations.
Other Safety resources
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies