Teaching Science 2.0

CAT 23-Directed Paraphrasing

Teacher:

Nancy Bryant

Context:

This week we have been studying the history of the atom. We have discussed Aristotle, Democritus, Thomson, Rutherford, Dalton, and Bohr.

Background:

The direct paraphrase CAT gave the students an opportunity to explain in their own words what they had learned that day.  It was also kind of a game, since they were supposed to be telling a younger student about an experiment.  I thought this class would most benefit from some reform, and I know that asking them to paraphrase a concept also helps their analysis and critical thinking skills, which are both long term goals for the class. My goal in this discussion is to convince students that we can study atoms even though we can’t see them, and to help them understand how we know there are positive and negative charges in an atom.

Task:

After discussing Thomson and Rutherford’s experiments I told the class that I wanted them to give feedback on an index card.  They would not receive a grade and they did not need to put their names on them. The assignment was, “In four or five sentences, paraphrase Thomson’s experiment.  You are writing to a 7^th grade student who refuses to believe that electrons are real because he can’t see them.”  I gave them about 5 minutes to write their responses. Each of the responses was logged in the chart based on how the student stated each concept.  The five concepts are listed below.

Concept #1 -Thomson did not know what composed atoms

Concept #2- The cathode ray tube was filled with atoms

Concept #3 - Like charges repel- unlike charges attract,

Concept #4- The beam of gas moved toward the positive plate and away from the negative plate

Concept #5-Because the beam of gas was attracted to the positive plate, the beam must have negative charges in it.

Results:

I see three types of responses in this activity.  One type of response is the student who begins well with some background information, but then seems to lose sight of the conclusion he is trying to reach.

The second category, in which the explanation had no background, but started with the …fact that like charges repel and unlike charges attract.

background information and also arrived at the conclusion stated in some way

Closing the Loop:

I read through the student responses before the next class, made notes on each card, and returned the cards to the students.  I told them that I had learned that we needed to focus more on the conclusion of each experiment so that they could understand its importance.  We discussed Thomson’s experiment again, with the students supplying the steps of the experiment verbally.  I also led an activity that day which led the students to draw conclusions based on their observations, hoping to give them practice in critical thinking.

Reflection:

This activity definitely has helped me understand how I need to constantly reform teaching methods to help students learn more completely.  In the past I would have assumed that most of the students understood the concepts revealed in Thomson’s experiment and then I would have continued on to other topics.  One issue I have discovered is that most students take longer to master the material than I ever believe possible. If I use this assessment technique again- which I plan to do- I will narrow the question more or add more prompts.  Another option would be to change the question to be more basic and just use question #3 in a different form.

Examples:

Source:

Angelo, T.A. & Cross, P.K. (1993). Classroom Assessment Techniques (2nd ed.). San Francisco: Jossey-Bass.

Acknowledgement: The author completed this assessment while a student at Montana State University