In 10th grade Chemistry, we're exploring properties that help us investigate and understand materials.
Our Block 1 theme is Properties. We will explore the distinguishing characteristics of materials from a variety of perspectives. We started out by thinking about the properties of chemicals relevant for our safety in the lab. This included chemical properties related to chemical changes or reactivity, such as flammability or corrosivity. We also talked about biological properties, such as toxicity. We used these discussion to draft lab safety guidelines as a group.
Our first lab involved a collection of white “powders” available at ordinary grocery stores. Students were given four substances identified by codes, and asked to figure out as much as they could about each substance. I expect to do several labs like this during the block (and perhaps future blocks), in which students apply increasingly sophisticated techniques to identify and distinguish materials; sometimes procedures will be provided and sometimes they won’t. Ongoing projects like the white powder challenge can also motivate other lab work we do. For example, when we study reactions, students may discover techniques they can use to suggest the ions that might be present in a sample.
Before moving on to chemical properties and exploring simple reaction patterns, we’ll study physical properties and some thermochemistry, including enthalpy, phase changes, heat capacity and calorimetry. We’ll do experiments to identify metal samples using physical properties, look at solubility and heats of solution, and perhaps identify organic liquids or solutions using physical properties. This will also provide a good place to start analyzing experimental errors in depth.
In addition to lab work, we’ll spend some class time on standard chemical skills including calculations and writing equations. I’ll offer a mix of exercises and challenging problems, and give students time to work in class, using each other and myself as resources. We did this on Thursday, and I really enjoyed how—almost completely without lecture introduction—the students took a few hints and ran with them to solve problems that college students might struggle with.
Block 1 is also a great time to get a feel for the history of chemistry and how we know what we know. Readings so far have included a description of recreating alchemical processes in a modern lab and an excerpt from Lavoisier’s chemistry textbook. Throughout the year, I plan to offer enrichment readings for interested students; this block they will focus on history of chemistry. By the end of the block, I hope students will have a feel for what chemical research and knowledge looked like up to 1800 or so, including basic patterns of reactivity and apparatus to observe them, types of measurements made, and concepts used to explain results and guide further work.
-- Emily Eames