These tenets set PBL (the big once-per-semester projects) apart from day to day activities and inquiry:
PBL poses an authentic problem with multiple solutions.
PBL requires core subject knowledge to propose solutions to a problem to an authentic audience.
Have you read “Making Thinking Visible”? You should. It focuses on making student thinking visible to the teacher. While still learning to use the visible thinking routines, I really feel more conscious of students’ understandings than ever.
Here is a sample activity that I adapted to fit my honor chemistry students’ needs:
In a recent contribution to ChemEd X "Stoichiometry is Easy", the author states that he has "vacillated over the years between using an algorithmic method, and an inquiry-based approach to teaching stoichiometry. " I would like to suggest that there is another approach to mastering stoichiometry and that it should precede the algorithmic one: it is the conceptual approach based on a particle model to represent the species involved in chemical reactions.
This article describes a three week lesson plan for teaching stoichiometry using an algorithmic method. Two labs (one designed as a laboratory quiz) several cooperative learning exercises, student worksheets and guided instructional frameworks (forcing students to develop good habits in writing measures and doing problem solving) are included. The highlight of the lessons is the "chemistry carol" (based on Felix Mendelssohn's music for "Hark! The Herald Angels Sing") in which students recite a five-step algorithm for completing stoichiometry problems.
This worksheet is intended to be used as a "Guided Instructional Activity" (GIA). Students read a statement that gives a either a conversion factor or a pair of related measures and then write the information as two equivalent fractions ("conversion factors") and as an equality. In each representation, students are directed to give the numeral of the measure, unit, and identity of the chemical.
This set of three worksheets are intended to be used as collaborative "Guided Instructional Activities" (GIAs). Two students cooperate to complete the steps of a stoichiometry problem, alternately doing parts of the process as they explain what they are doing and evaluate their partner's work.
This worksheet is intended to be used as a "Guided Instructional Activity" (GIA). It asks students to find the molar mass of selected elements and write the molar mass as two equivalent fractions ("conversion factors") and as an equality. It is designed to help develop good habits in representing molar mass and other conversion factors, and to emphasize the idea that a conversion factor has a numerator and denominator that "name" identical quantities using different measures.
Given the amount of one reactant, students must use stoichiometry to find the ideal amount of the second reagent to use to create purple fireworks. The teacher ignites each groups' fireworks. Ideal mixture create little or no ash. Student assignment sheet with directions (and different initial amounts) plus teacher information and sample answers are included. This is an exciting and engaging activity that can be used as a stoichiometry quiz.
Moles, mole ratios and stoichiometry have been frustrating topics for many of my chemistry students. The MOLE and Avogadro’s number get tangled up in other Chemistry jargon and students have stared at me like I am speaking another language. I have been around long enough to know this is a problem that many of us have faced. I have tried many ideas that have helped and I want to share a few.
