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September 2015 | Nuts & Bolts
Teaching Chemistry on a Budget
By Audrey Smeltzer-Schwab
Classroom Activities, Demos & Labs
As chemistry teachers, it is critical that we incorporate as much experimentation and activities as possible into our lessons. Since chemistry is abstract, students need active engagement so they can construct meaningful understanding. However, in the current state of education, when funding is limited, it can be difficult—the financial burden to try new experiments or activities may fall on the teacher. Throughout my years of teaching, I faced the dilemma of balancing the expense and the desire to create a better learning environment for my students. Therefore, I offer a few suggestions.
For many teachers (like me), this school year’s budget was due last year. Consequently, if I find a new experiment that I wish to implement immediately, the cost falls on me. Knowing this, when I search the Internet for a “new” experiment, I frequently add the search criteria “with household items.” Upon finding a potential experiment, I head to the dollar store or the bargain outlet for the supplies. If I cannot find an experiment that correctly demonstrates the topic or if the materials are too expensive, I try a traditional experiment with household items to see if it works. A further option when evaluating a new experiment is to use community resources: contacting a local college, science coach, or a traveling science van could allow students to experience different labs not typically available in a high school setting.
You can also use durable goods to save money. Most of my activities use items purchased at the dollar store or the bargain outlet. I use beads or buttons to represent electrons that students manipulate in the bonding unit. I also maximize school supplies—the cardboard at the bottom of a ream of paper is quite useful. I use it to make “element cards” for students. Another valuable lesson is to become friends with the specialty-area teachers. Many times, art teachers have extra supplies that they can share with you. Furthermore, I have students use their personal items for activities. For example, when I teach qualitative versus quantitative observations, I have students play a guessing game where they describe their personal objects in terms of qualitative and quantitative features.
I use the elements cards that I made from the cardboard from reams of paper and the beads that I purchased at the dollar store. Using an element card, students use beads to represent the electrons in a Lewis dot structure. Figure 1 shows this example for calcium.
Then I have them do the same for another element, such as oxygen (Figure 2).
During this activity, I question students about the octet rule, asking whether they think it would be easier for calcium to lose two electrons or to gain six electrons. Using the element cards and beads as a visual aid, students understand that they should move the electrons from calcium to oxygen so both elements are stable (Figure 3).
Finally, I ask students whether both elements satisfy the octet rule. From that, students express how many electrons calcium lost and how many electrons oxygen gained. Students then write the ion symbol for calcium with its correct charge (Ca2+) and the ion symbol for oxygen with its correct charge (O2–). Ultimately, students come up with the correct chemical formula for calcium oxide (Figure 4).
The first time through the process I guide students. After that, they work through the various element cards provided, predict the charges for each element, and determine the correct chemical formula for each ionic molecule that they create.
The Internet is a great resource. Two of my go-to labs use products I purchase all at the dollar store. I found these labs by searching for the specific topic to investigate: “limiting reactant and stoichiometry” and then I included “household items.” The first lab is a limiting reactant lab activity that uses baking soda and vinegar. The second lab also uses baking soda and vinegar, but this one demonstrates stoichiometry principles. With a simple Internet search and inexpensive items purchased at the dollar store, students can perform valuable experiments that demonstrate important chemistry concepts.
It is important that students are actively engaged in their learning experiences. However, I understand the frustration of teaching chemistry on a budget. It is important that we continue to strive for the success of our students by improving our inventory of activities and experiments while creatively working with a limited budget.
Note from the editor: The AACT library is another great resource. While searching the Internet for resources can result in good finds, our library contains more than 200 resources submitted by teachers of chemistry. Why not start there? And if we don't have what you're looking for, then search the rest of the web. If you find something great, share it with us so others can use it too!