What is the most appropriate method for informally assessing students' lab safety practices?

Observing students during experiments is the most appropriate method for informally assessing their lab safety practices because it allows the teacher to see firsthand how students behave in a real-time, hands-on environment. This observation enables the teacher to assess students' adherence to safety protocols, such as the proper use of equipment, wearing personal protective equipment, and following established safety guidelines.

Direct observation provides immediate insights into students' understanding of safety practices and their ability to apply that knowledge effectively while engaged in laboratory activities. Furthermore, teachers can provide prompt feedback and guidance based on what they observe, which can enhance learning and promote safer practices in future experiments.

In contrast, reviewing lab report procedures or assigning an essay on lab procedures may provide insights into students' theoretical knowledge but do not assess their practical application of safety in the lab setting. Likewise, giving an impromptu quiz may measure recall of safety information but does not involve observing the actual implementation of those safety practices during experiments. Thus, direct observation is essential for comprehensive and effective informal assessment of lab safety practices.