Can it reflect light? Is it a plant? Is it made of cells? These questions are among more than 100 formative assessment probes developed by Page Keeley and her colleagues to help teachers elicit information about what students think about key science concepts. A capacity crowd at Keeley’s Seattle conference session turned out to learn more about these powerful tools and how to use them in the classroom to delve deeper into student thinking. Keeley began her session, “What Were They Thinking?” by pointing out that teachers realize “students don’t come to us as empty vessels; they have preconceptions about science.”  A teacher who brings those student ideas to the surface can challenge students’ existing ideas and encourage them to think more deeply about a science concept. As Keeley noted, lab equipment like Vernier probes can help us see below the surface and collect additional information, thereby deepening our knowledge. The formative assessment probe is a specific type of question that similarly can help us look beneath the surface to learn more about student thinking.
The probes in Uncovering Student Ideas in Science are engaging questions that promote a lot of talk, argumentation, and thought among students. Teachers who use probes at the beginning of a lesson or unit help make students’ thinking visible to the teacher, the class, and sometimes to the students themselves, who might not have realized their ideas until they were brought to the surface in a probe activity. One probe that Keeley highlighted is “Can It Reflect Light?” Students are given a list of items such as water, soil, mirror, rusty nail, and red apple and asked to sort them into items that reflect light and items that do not. The second part of these activity is the most powerful part, Keeley said, because students are then asked to explain their reasoning for the sorted lists they created. The student explanations give teachers rich insights into preconceptions or gaps in students’ knowledge, thereby guiding the teacher in how to structure an ensuing lesson. Several common ideas students have about light and reflection include the assumption that only light-colored or shiny objects reflect light, for example. A teacher might structure a lesson that offers numerous opportunities for students to explore light and reflectivity to gain first-hand understanding that “if you can see it, it is reflecting light.”
Several different types of questions are used in the probes, including one Keeley called “Familiar Phenomena Probes.” These probes are designed to get at students’ thinking about familiar events. Examples are “Wet Jeans,” in which students ponder where the water has “gone” from a pair of wet jeans that dried while hanging on a clothesline, and “What’s in the Bubbles?”, in which students discuss what they think is in the bubbles that form in boiling water. The probes “What’s in the Bubbles?” and “Can It Reflect Light?” are available for download in the NSTA Science Store. Keeley’s session prompted a lively discussion among the teachers present about commonly held misconceptions and how strongly held they can become among students. Formative assessment probes like those in Uncovering Student Ideas in Science can be just the tool for teachers to employ when urging students to reexamine their existing ideas and deepen their understanding about important concepts in science.