A study was conducted with ninth-grade students (n=242) who studied according to this approach. Pre- and post-questionnaires, administered to the students, included a few items that deal with Newton's third law (N3) from the Force Concept Inventory.¹⁶ These items are considered to be difficult because of their counterintuitive nature. Table I shows the results on these items.

As indicated in the table the average <g> of these students is high as compared with achievements of college-level students studying by traditional methods (for example, a value of <g>=0.28 was reported by Redish¹⁷ et al.). These students demonstrated in interviews an improved ability to explain and predict phenomena using physics ideas. In pre-interviews conducted with some of these students (n=69), they used only intuitive reasoning and colloquial language in explaining and predicting phenomena, while in the post interviews they showed a more expert-like performance^13,14 using physical terms, physics principles, and force diagrams. The following excerpt illustrates the nature of explanations given by students after instruction (see Fig. 6):

Interviewer: What will happen to the rocket balloon when the air is released from the balloon?

Student: Because there is an interaction the air exerts a force on the balloon this way (points to the correct direction).

Interviewer: What will happen to the rocket balloon?

Student: It will move this way (correct), if the pushing force is greater than the friction force.

Interviewer: Let's take something else Suppose you release the balloon but it doesn't move?

Student: The friction force can exert a force up to a certain magnitude and when you have a larger magnitude the object will move but here this didn't happen so the balloon didn't move.

Figure 6.

In this sample, the student uses formal language and handles friction very well. He is also showing a more expert-like performance and mastery of understanding performances that were on focus (prediction and explaining).

A selected item from the Israeli matriculation examination in physics that dealt with N3 (see Fig. 7) was added to the post-questionnaire. Results on this matriculation question are shown in Table II showing that the ninth-grade students scored better in this N3 matriculation item than high school students majoring in physics.

Figure 7.

Attitude questionnaires, administered to the students after instruction, show that students believed that the strategy used in this method helped them in analyzing situations and that they would like to study other disciplines in the same manner as they had studied physics.

The teaching method was introduced to junior high school science teachers (n=150) through inservice training courses entitled “Who's Afraid of Physics?” Teachers report that they gained self-confidence in their ability to explain everyday phenomena, changed their views about the relevance and interest of physics to the students, and were willing to implement the method in their classes.