Knowledge of Student Understandings
As the course progressed and the students participated in the JiTT activities, it became evident that indeed many students had limited content knowledge in science and held partial and naive understandings of many scientific concepts. For example, activity three probed student understanding of the difference between heat and temperature, posing the question, “Which object contains the most heat, a boiling pot of water or a gigantic iceberg?” Students were asked to explain their choice with reference to their definition of heat. As the literature predicted, student responses varied considerably, ranging from those who could answer the question with high precision and accuracy to those who demonstrated very simplistic notions of these concepts. For instance, almost a fifth of the students stated that heat was how hot or cold an object is and chose the teapot because it was hot. This is reflected in the following pre-service comment:
An iceberg is frozen, very cold to touch and does not generate any heat. But a pot of boiling water produces a lot of heat. (Student E)
Less than a quarter of the students were able to recognize and explain the difference between heat and temperature, as illustrated below:
84 P. Osmond and K. Goodnough
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Although the tea is steaming hot and an iceberg would be thought of as freezing, the iceberg is technically warmer then the boiling tea... the iceberg is so massive that overall it has more energy which is actually more heat. (Student H)
Likewise, in JiTT Activity two, which focused on the freezing of water (see the Appendix), less than half the students recognized a period of constant temperature as a phase change and only five students could relate the concept of latent heat as it applied to the situation. My critical friend and I discussed student responses to this question in the post-activity interview:
A number of the students were able to recognize that the temperature remained at 2 degrees for a long period of time and they recognized that this indicated that there was a phase change going on at that time. Very few of them could then elaborate on exactly how a phase change occurs or what’s happening to the molecules as phase change occurs or, more importantly, what the question had asked – why the temperature remains constant during a phase change. (Pamela, Post-activity-two interview)
Furthermore, the JiTT responses allowed me to identify a common misconception in my students’ understanding of that particular concept in particle theory:
The majority of students held the misconception that the water molecules were going to move closer together... which is true for the vast majority of the substances on the planet but water is actually the exception to that rule. There was only one student who picked up on the fact that water, because of its structure and because of the way the hydrogen bonds form, when it changes from a liquid to a solid, water actually expands when it freezes. Then we talked about practical things like what happens if you were to put a can of soda in the freezer? What happens if you leave it and you forget about it? Well, it explodes. Why did that happen? Well, the liquid expanded as opposed to contracting. (Pamela, Post-activity-two interview)