Teacher manual for AP* and Advanced Chemistry labs. Has both the printed version and a flash drive with teacher tips, a PDF of teacher version and editable Word student version.
Exploring chemical and physical changes in a laboratory experiment is not as easy as one may think. The general appearance of a substance can tell us something about events on the molecular level, but this provides limited information. Measuring parameters like conductivity, temperature, pH, or pressure with digital sensors can provide data that helps us understand more about what is going on, but even that may not be enough to completely understand that which is too small to see. This is the challenge of being a chemist.
Students compare various physical and chemical changes and analyze them for ambiguity while also gaining understanding of sensors and representing reactions at the particulate level.
The student is able to use aspects of particulate models (i.e., particle, spacing, motion and forces of attraction) to reason about observed differences between solid and liquid phases and among solid and liquid materials. The student is able to refine multiple representations of a sample of mater in the gas phase to accurately represent the effect of changes in macroscopic properties on the sample. Students can translate among macroscopic observations of change, chemical equations and particle views. The student is able to evaluate the classification of a process as a physical change, chemical change, or ambiguous change based on both macroscopic observations and the distinction between rearrangement of covalent interactions and noncovalent interactions. The student can support the claim about whether a process is a chemical or physical change (or may be classified as both) based on whether the process involves changes in intramolecular versus intermolecular interactions.
This experiment may require software and an interface for data collection.