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Asia-Pacific Forum on Science Learning and Teaching, Volume 17, Issue 2, Article 2 (Dec., 2016) |
At the pretest and posttest, the students answered the multiple-choice questions in the first tier of the conceptual test and also the section that asked for the reasons for their answers, which constituted the second tier of the test, and the responses were reviewed together and determined for each item separately. After the application of the Energy Conceptual pre- and posttest, the students' responses were scored as described in the Methods section and then separated into categories.
A review of the pretest data showed that the responses of the CBG were deficient by 90% or more in items 12, 13 and 16 of the test and that the students had misconceptions; it was also seen that test items 2, 3, 4 5, 6, 11, 14 and 15 were also deficient and reflected misconceptions on the part of the majority of the group. In the TIG, the deficient conceptualization in the responses given to item 13 was 90% and test items 4, 5, 6, 8, 9, 12, 14, 15 and 16 showed the majority of the group had deficient notions and misconceptions. In addition, in both groups, full understanding percentages were markedly low and the same was also seen in items 1, 2, 4, 5, 7, 9, 10, 11, 12, 13 and 15. In the light of all of these results, it may be said that the students in both groups had deficient knowledge and misconceptions prior to the instruction.
When the posttest data were reviewed, the conclusion was reached that the full understanding percentages of the students in the study group (CBG) were higher than those of the students in the control group (TIG) in all the items except items 2, 7 and 11. When the pretest is compared with the posttest in Table 2, it can be seen that the total scores of the study group in the first and second tiers of the posttest showed no difference in items 13 and 16 but displayed increases in all the rest of the items. In the control group, however, it was found that the first and second steps of the posttest showed a decrease in total scores in item 1, no change in items 5 and 16, and increases in all of the rest of the items.
Table 2 demonstrates the difference in percentages in the pre- and posttest of the two-tier Energy Conceptual Test in the two groups. The difference was derived from subtracting the percentages on the pretest from the percentages on the posttest. Table 2 represents increases as (+), decreases as (-) and no change as (0).
Table 2. Pretest-Posttest Percentage Changes in student responses to the two-tier test items by Understanding Categories
Cased-Based Group (N=30)
Traditional Instruction Group (N=30)
Number of Items
SUC
(%)PUC
(%)SMC
(%)C(NU/NR)
(%)SUC
(%)PUC
(%)SMC
(%)C(NU/NR)
(%)1
+13.3
+6.7
-20.0
0
+3.3
0
-16.7
+13.3
2
+16.7
+6.7
+6.7
-30.0
+30.0
+6.7
-26.7
-10.0
3
+36.7
+13.3
+3.3
-53.3
0
0
+36.7
-36.7
4
+6.7
+10.0
+13.3
-30.0
0
+20.0
-10.0
-10.0
5
+6.7
+16.7
-6.7
-16.7
0
0
0
0
6
+10.0
+6.7
-3.3
-13.3
+3.3
+10.0
+13.3
-26.7
7
0
+50
-56.7
+6.7
0
+13.3
+6.7
-20.0
8
+30.0
-16.7
+3.3
-16.7
+26.7
+20.0
0
-46.7
9
+16.7
-6.7
0
-10.0
+3.3
+3.3
+10.0
-16.7
10
+26.7
-6.7
-23.3
+3.3
+3.3
+26.7
-23.3
-6.7
11
+3.3
+13.3
+23.3
-40.0
+6.7
+30.0
-6.7
-30.0
12
+3.3
+3.3
+40.0
-46.7
0
+13.3
+6.7
-20.0
13
+3.3
-3.3
-3.3
+3.3
0
+3.3
-3.3
0
14
+53.3
+13.3
+3.3
-70.0
+33.3
+20.0
+13.3
-66.7
15
+26.7
+10.0
+13.3
-50.0
+20.0
+36.7
+3.3
-60.0
16
0
0
0
0
0
+3.3
-6.7
+3.3
Note: SUC: Sound Understanding Change; PUC: Partial Understanding Change; SMC: Specific Misconception Change; C(NU/NR): Change in No Understanding or No Response. Figures have been rounded off. When examined, it will be seen that Table 2 demonstrates that increase in the number of items in sound understanding, which was above 10% (f=3), was higher in the study group compared with the control group. The changes that remained below 10% were considered negligible. Some items showed no change at all in sound understanding. The number of items where there was no change in sound understanding was higher than in the control group.
In addition to the data given above, the alternative notions (35) that emerged from the responses of both groups of students in the Energy Conceptual Pretest and the misconceptions (9) that emerged on the Posttest are shown below:
- To have an object perform physical work, force must be applied to it to get it to move.
- Work is performed when force is applied to an object.
- Physical work is performed if the object changes its place.
- Work only occurs when objects are pushed horizontally.
- Work occurs when an object is touched.
- Moving objects perform work in the physical sense.
- More movement means more work.
- When force is exerted, the object must move.
- Force moves horizontally.*
- If the force is exerted perpendicular to the direction of the object, this means that physical work has been performed.*
- A leaf breaking off a branch and falling to the ground applies potential energy relative to the ground.
- A leaf breaking off a branch and falling to the ground expends kinetic energy.
- If the object falls to the ground, kinetic energy is released.
- Kinetic energy diminishes as the leaf falls down from the branch.
- Potential energy increases as the leaf falls down from the branch.
- A hairdryer conducts heat.
- Electrical energy cannot be converted into kinetic energy.
- Because we exert force on a basketball when we're throwing it, potential energy increases.
- Potential energy diminishes as altitude increases.
- An increase in the energy spent doing the same work increases efficiency.
- An increase in the speed of an object increases its efficiency.*
- If a horizontal object changes place, kinetic energy will increase.
- Potential energy diminishes when there is motion, but kinetic energy does not change.
- Kinetic energy will increase as long as movement is on a flat plane.*
- When the same work is done in a shorter time, more energy is spent.*
- When the same work is done in a shorter time, more power is spent.
- When altitude increases, the potential energy spent increases too.
- When a book is lifted, potential energy is less because work is being performed.
- Increasing the altitude of an object that is already high up from the ground does not change its potential energy.
- After the dam gates are opened, gravity takes hold.
- Turbines apply kinetic energy by turning.
- Renewable energy sources are not natural, they are artificial resources.
- If an object moves, it gains potential energy.
- When an object's direction of motion changes, the object gains kinetic energy.
- If the object changes place, it gains potential energy.
- The object gained potential energy because it was moved.*
- The more an object moves, the more the kinetic energy.*
- The force applied to an object is equal to kinetic energy.*
- The movement of an object on a steep incline is more difficult and signifies more work.
- The higher the incline, the harder and the more the work that is performed.
- Energy is spent only during the motion.
- We spend energy because we move.
- Heat energy is found in objects used and cannot be transferred to other materials.
- Friction does not lead to the loss of mechanical energy in the form of heat; just the opposite, it produces heat.*
Most of the alternative concepts in the above list were observed in the responses given in the pretest. Some of the alternative concepts were found in both the pretest and in the posttest. Some of the items on the list (with the asterisk) appeared in the responses in the posttest. One of the reasons these appeared later on may have been that in general, the items that had been left blank on the pretest were answered in the posttest. Also, both groups provided similar alternative concepts and misconceptions but there were more alternative concepts and misconceptions in the control group on both the pretest and the posttest.
