A central part of every Chemistry course is the structure of the atom. And in many courses, a portion of the discussion is devoted to how our understanding has evolved over time. This discussion usually includes some names of scientists and their discoveries and the manner in which their discovery led to an adjustment of a previously held theory regarding the atom. Key figures include John Dalton, J.J. Thomson, Ernest Rutherford, Neils Bohr, Werner Heinsenberg, and Erwin Schrodinger. Classic experimental findings include the interaction between cathode rays and the N and S pole of a magnet, the interaction of alpha particles with a gold foil, the analysis of the line spectra of Hydrogen, the discovery of wave-particle duality, and Heisenberg's idea of uncertainty with respect to precise knowledge of position and momentum. This Concept Builder probes many of these historical figures, findings, and the subsequent models that emerged from the findings. Some basic understanding of the models of Dalton, Thomson, Rutherford, Bohr, and Schrodinger will be required. We recommend
previewing the questions before you assign this to students. There are four different activities, each having a different emphasis. They are described as
Activity 1:
Scientists and Models - learners associate the name of a scientist with the name of the atomic model that they developed.
Activity 2:
Discoveries and Models - learners associate a specific discovery or experiment with a description of a model that the finding led to.
Activity 3:
Electrons and Models - learners associate the name of a model with a description of what the model uniquely proposes about the electron.
Activity 4:
Diagrams and Models - learners associate a pictoral representation of a model with the name of the model.
When creating questions for this Concept Builder, we tried to emphasize what the unique contribution of each scientists was at that point in history. It might be helpful to point this out to students. For instance, one scientist might have been the one to propose that the atom contained negatively-charged particles. All subsequent models likely proposed the same thing but the statement "Proposed the existence of negatively charged particles in a sea of positive charge." is attributed to the scientist who first discovered this. Similarly, one scientist discovered the presence of nucleus filled with positive charge. All subsequent models include this idea. But the statement "Proposed that the + charge and mass of an atom is located in a centralized location." is attributed to the scientist who first discovered this.
In order to complete any of the activities, learners must successfully associate four pairs of ideas. Help is provided for each activity. When used with Task Tracker, the activity can be assigned as in-class or out-of-class work and student progress can be tracked in our Task Tracker database. Teachers using the Concept Builder with their classes should preview the activity (or view the
Questions in a separate file) in order to judge which activities would be most appropriate for their students.
Unlike most of our Concept Builders, this Concept Builder has little means of providing question randomization. The location of the terms on the Matching Pairs grid is randomized but it is always the same 8 terms for every student. If a student mis-matches a pair, then they will have to re-start the activity. The Matching Pairs grid is re-randomized on re-start and terms are positioned at new locations on the grid. This forces a good deal of concentration on students' part as they seek to remember which terms were successfully paired and unsuccessfully paired on previous attempts.
The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each question group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise.