We do at least four, formal lab reports in each science class. Why? Several, online home-school programs require four lab reports. (Mother of Divine Grace and Kolbe Academy require four lab reports, as a minimum.) However, I assess labs all the time. Here is how.
Sometimes, lab assessment is informal. Let’s say hypothetically, we struggled with the Spinach Leaf Photosynthesis Lab and were frustrated beyond measure trying to get the disks to sink and FINALLY rise in the bicarbonate solution. Arrrgggh. Did everyone make a valiant effort? Were we all on task? Job done. I am not going to torture or test the kids’ patience any more. I do the same thing for a simple lab, such as Reaction in a Bag. I ask each group to explain what happened. If the team did not happen to note the temperature change, they redo the lab. Otherwise, I award points to everyone completing the lab.
One method is CER. Here is a template. For example, we can do Density of Metals lab, comparing volume by displacement and volume by direct measurement. The kids guess which method is more accurate. The teen might claim, ‘Volume by displacement is more accurate than volume measured with a ruler. (Really.) The student completes the lab and compares density values. The data table is evidence. Finally, the reasoning is that measured with a ruler or calipers have a lower percent error. The kid can scratch out his or her original claim and revise it. CER works well for The Specific Heat Capacity of Metals lab, too. The kiddos make a guess claiming which metal has the highest heat capacity. Then they do the lab; the data table supplies evidence. Finally, the reasoning is a statement of which meal has the highest heat capacity. The kids do the lab, collect data, and analyze the results. At this point, we focus on data collection, organization, and how to create spreadsheets.
As often as possible, the data sheet becomes the assessment tool. The kids collect class data and summarize it in a spreadsheet. The lab grade is a completed spread sheet. We work on the lab title. For instance, it’s important to specify which lab, rather than ‘Vincent’s Bio Lab’. We remind kids not to hard code numbers. (If you take an average on a calculator and put the number in a spreadsheet, it’s called hard coding a number. Teens should create formulas, instead.) In all, the spreadsheet represents a significant amount of work and constitutes the lab grade.
Sometimes the lab assessment amounts to calculations—usually in a data sheet. One example is Flinn’s Flame Test lab. Note the data table in the lab. The kids complete data table #2. Once their answers are correct, they earn credit for the lab. Similarly, we do the White Powder Lab. The kids run tests on a dozen known, white powders. Then they use their notes to test twelve unknown white powders—the same powders mixed up. The grade is getting all 12 white powders correct. The lab takes a minimum of two days—loads of work. The grading takes a few minutes. The kids are learning about qualitative analysis. They like that the grade is based on solving a puzzle, which powders are which.
Finally, we write Formal Lab Reports with a lab report rubric. Yes, the rubric is more of a score sheet. I spend the bulk of my time editing the reports. The kids struggle to report materials in complete sentences rather than a list. I insist the report is written in the third person. The kids slip into the imperative, instead. We have long, uncomfortable conversations about what constitutes plagiarism. Kids have trouble writing both a background paragraph and a conclusion. It takes two or three revisions before I accept the lab report as complete. This is one reason I only require four reports. I will combine a few labs into one report. For example, the teens are doing Nerve Experiments. They’ll combine all of the experiments into one big lab. Another example are Dissections; we combined the dissections, sketches, and photos into one big, lab report. You could combine Candy Chromatography and Paper Chromatography into one lab report. Kids like this approach; it feels like less work.
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