Research in Secondary Science Education:
SED 600: Spring 2007
John Olson
Video Analysis
The lesson I video taped for this assignment had to do with the periodic table, specifically, what was the source of the atomic number and atomic mass units, and what those numbers actually represented. Students in my classroom were given cups with sets of marbles wrapped inside a napkin. Dark marbles represented protons, clear marbles represented protons, and the napkin surrounding them represented the electron cloud. As a class, we “dissected” the atom models one by one, counting the protons and neutrons, and recording the findings on a data chart. Each student made a copy of the chart in their notebook. The lesson was designed to reinforce the concepts in a project they were creating on the periodic table. For perspective, I video taped this same lesson three times throughout the day.
I observed that the design of this lesson worked well in demonstrating the concept of atomic number and atomic mass. Students were actually able to handle and count protons and neutrons, and see the relationship between the numbers on the chart and the models they were working with. Working with models whenever possible is one of my preferred modes of teaching.
I felt that the way I led the direction of the discovery with questions based on their prior knowledge was competently done. I observed that I was usually remembering to pause, allowing students time to find an answer. I also asked the whole class to raise their hands when they knew an answer, and then called on one person to verify answers. Students were engaged in looking at the periodic table and finding information.
The way we collected and interpreted the data from the activity was clear and consistent, which allowed the students to quantify the models they observed and make comparisons. The students recorded the same data in their notebooks, keeping them engaged in the data collection process. The students who handled the actual models were highly engaged, more so than the students who were observing.
Students knew the expectations and I utilized pauses, the “teacher stare”, and a low key voice to correct any disruptive behavior. I had one student whose behavior became a distraction. I had to separate him from the group, but later called on him for an answer to keep him involved in the discussion.
Directly after the lesson, the students worked on a page in their project where they explained to their would be readers what each of the numbers meant, so I felt the students were well prepared for the follow-up activity.
The specific objective of this lesson was to illustrate the numbers found around each element in the periodic table. I found that the lesson design itself was a creative way to help meet this objective, helping students to understand where these numbers came from and what they represented.

Although my questioning was fairly balanced, there were times when I was unclear on how students should respond. I would ask for a show of hands, then for everyone to say aloud the answer. On another occasion, I just asked for the answer from the group, and several were unprepared to answer. A few times, I acknowledged a student who called out. There are times in my classroom where this is allowed, depending on the type of dialog, but in this lesson’s format, it actually distracted me from allowing other students time to think of a response.
I found on the tape that my voice was fairly monotone and flat. I found listening to myself speaking became a little tedious, so I imagine the students must also find it tedious from time to time. This “droning” made aware of the fact that I was controlling the lesson, when in fact the students could have easily stepped up and verbalized the process, the data, and their observations. If I had thought to remove myself from the lesson and had served as a mediator instead of director, the activity would probably have been much more dynamic and engaging, and the students would have had a more vested interest in the progression of the lesson.
Were I to present this lesson again, I would increase the number of samples and have it as a small group activity. I would demonstrate the first few examples, then have the students in their lab groups finish the activity independently. After that, I would have each group present their findings instead of just recording them.
From my observations during the lesson, and from what is visible on the tape, students were learning the two concepts I was trying to clarify. Students were able to find the names of the elements modeled in the activity in their periodic table based on the number of protons they counted, as recorded in their data charts. I was seeing a lot of hands raised, and I was getting appropriate responses to my questions.
The students who worked directly with the models were able to give me the correct mass units for the particles in the “atoms” they were handling. I could only verify that the other students picked up this concept by their follow-up work in their projects. Since this part carried over to the next day, there were some students who needed additional instruction in the meaning of atomic mass. The idea of atomic number was better understood and retained, from my observations of their projects. The allusion to isotopes was not clear enough for the students to really grasp.
Through questioning at the start of the lesson, students demonstrated prior knowledge. They were able to identify the parts of the models that represented protons, neutrons, and the electron cloud. At the start of second quarter, students drew and labeled models of an atom, including as much information as they knew. The samples I collected showed that pretty much across the board, entering 8 th graders had no working knowledge of the parts of an atom. Their responses in this activity demonstrated that they had developed a working understanding of the modern model, which they were able to apply to the napkin/marble model we worked with.
(They got that the napkin was the electron cloud, that the marbles were the particles of the nucleus.)
Watching oneself teach on a video is an enlightening, if not wholly unpleasant experience.
Taking a critical look and oneself, as objectively as possible, was not an easy task, but it did prove to be an excellent tool for self-evaluation.