A Year without Procedures: Removing Procedures from Chemistry Labs Creates Opportunities for Student Inquiry
2005; Taylor & Francis; Volume: 72; Issue: 7 Linguagem: Inglês
ISSN
1943-4871
Autores Tópico(s)Biomedical and Engineering Education
ResumoMost high school chemistry labs contain detailed procedures on how to perform experiments, collect data, and analyze findings. These step-by-step instructions often eliminate opportunities for inquiry, higher levels of thinking, and the sense of accomplishment students find through independent discovery. [ILLUSTRATION OMITTED] For these reasons, two years ago I elected to remove specifically outlined procedures from many chemistry labs in my classroom. By doing so, I promoted collaboration between students as they designed their own steps and illustrated that more than one way exists to solve a problem. I challenged students and let them experience the scientific process and the reward of discovering answers on their own. This article describes a chemistry-based experimental year without procedures, but the concept can be applied to any scientific discipline. [ILLUSTRATION OMITTED] Reviewing the procedures Before introducing inquiry-based labs, I began by examining many of the current labs scheduled for our chemistry class. Could students be successful doing the lab without the procedures? Did they have enough background information? Would it be safe? I found that many labs could be done successfully without detailed procedures; summary descriptions of these labs are provided in Figure 1 (p. 56). To address safety, students were instructed at the beginning of the year on general chemical safety procedures and given a safety contract to read and sign. Prior to each lab, special reminders were given regarding specific chemicals; however, because these chemicals and their uses could change based on students' ideas, I required that all procedures be cleared with me before implementation. This procedure review gave me a chance to check for possible safety issues and question student lab design, although I did not usually correct student procedures unless they were unsafe. Reviewing lab designs also kept me busy during lab periods. Instead of providing and correcting procedures, I posed questions or problems to solve, and left it up to students to figure out the experimental steps. To develop procedures and conduct experiments, students typically brainstormed and worked in groups of four, although occasionally they worked in pairs and a couple of times as a whole class. Implementing inquiry The opening lab For Lab I (Figure 1), I gave students 16 substances--liquids, solutions, and solids--and asked that they describe the substances as thoroughly as possible, including differences and similarities. I intentionally provided a variety of chemicals that had different densities, colors, and odors, and that would change colors, produce precipitates, bubble, or solidify when mixed. This opening lab acted as a springboard for our unit on how chemists identify unknowns. In addition to visually observing the substances, students chose to examine solubility in water, melting points, odor, reactions in flames, and reactions with combining samples. Students were required to check with me before doing anything beyond visual observations and prior to disposal (I required a disposal check for each lab). If students needed supplies or chemicals to examine substances, they had to ask for these materials. I did not want to influence student choices by setting out particular supplies, such as Bunsen burners. After obtaining my safety approval, students who chose to put materials in the flame were surprised when one material turned red (strontium chloride) and others were perplexed when they added water to a white powder and it solidified (sodium polyacrylate). Several times during the lab, students excitedly showed me their findings. Over the next several labs, students proceeded to identify several of these 16 substances. To identify the first two, aluminum and zinc, density was used. I decided that determining density (Lab 2, Figure 1) was a formal lab procedure students could design on their own (Figure 2, p. …
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