Investigating Gas Laws
Gas Laws in the gases and the atmosphere unit are often introduced to the students in different representations (molecular, visual, graphical and formula) to enhance understanding in students. Many demos can be used to showcase the relationship of the different variables such as heat and volume in a balloon or a syringe. Each of these demos can then be further represented in graphical form to show the direct or indirect relationship between the variables. More often or not, a graph of a linear slope (positive or negative) is shown in the notes to show the relationships and is often regurgitated. To quantify the relationship, the formula of each respective law is then introduced, and the students get an ample amount of practice in solving for the unknown. However, this is where the students spend the most amount of time, with the least amount of conceptual understanding. Numerous worksheets are provided to the students on gas law calculations but the conceptual understanding of the relationship between variables is often overlooked. I have seen my students in my class regurgitate the formulas but when asked conceptual questions related to the laws, they would struggle. Another issue was that the students often have difficulties interpreting graphs of relationships. Although they are comfortable in remembering the relationships, whether direct, or indirect, they have difficulties relating the variables to a graph.
To enhance 21st century learning in chemistry classroom learning, this investigation allows students to work in small groups, and to use classroom materials to experimentally collect the same or similar results to the lab. If Boyles law is indeed relating pressure and volume, then they need to design, execute, evaluate, graph and communicate their results to the rest of the class. This allows the groups to 1st plan and design their experiment. and then tinker with their experimental design to successfully collect their data. The investigation culminates into a presentation piece where the students present their experimental design, and share their data with the class.
At the end of the activity, the students will have communicated, designed, planned, executed (scientifically I hope), evaluated, graphed, calculated, and presented the data after this activity.
Let me know your thoughts.
Here’s beta version of the investigation I have used: Gas Laws Investigation