4.2 Quantitative results
4.2.2 Results from post-test
At the end o f the ASEI teaching intervention, a post-test was administered to 22 learners to assess their sense-making o f the topic light and to evaluate the impact o f this intervention in influencing learners’ sense-making. Figure 3 and Table 6 below show the learners’ average percentage scores from the post-test.
Post-test for 22 learners
12 10 l/> L_ ai 8 to 6 M o o 4 2 0 0-29 30-39 40-49 50-59 60-69 70-79 Percentage range (%) ■ No of learnersFigure 3: Results from post-test
The distribution o f marks reflected in Figure 3 presents the percentage range o f marks scored by learners in the post-test: two learners scored marks within a range o f 40% to 49%, 10 learners scored marks within a range o f 50% to 59%, four learners scored marks within a range o f 70% to 79%, while one learner managed to score marks a range o f 80% to 100%. Unlike in the pre-test results, none of the learners obtained marks below 40% in the post-test.
According to NSSCO level Physical Science’s (2010) promotional requirements, a range o f 60% to 69% represents a C symbol which is equivalent to 5 points; a range o f 70% to 79% represents a B symbol which is equivalent to 6 points, while the range o f 80% to 100% represents an A symbol which is equivalent to 7 points. Figure 3 shows that 91% o f the 22 learners managed to score 50% and above in the post-test while only 9% o f them obtained marks below 50%. This is an indication that most learners were able to make sense o f concept o f light in answering most questions in the post-test.
The detailed analysis o f the scores for all questions in the post-test from all 22 learners is reflected in the Table 6 below.
Table 6: Detailed scores for post-test Question number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Total Marks per question 2 2 4 2 2 2 2 2 2 2 2 2 2 2 2 32 Learners L1 2 1 2 0 0 2 2 2 2 1 2 2 0 0 2 20 L2 2 1 2 0 1 1 1 1 0 1 2 2 2 0 2 18 L3 1 2 3 0 2 2 2 0 2 2 1 2 2 0 2 23 L4 2 2 4 0 0 0 1 1 1 2 2 2 1 1 2 21 L5 2 1 4 0 2 2 0 0 2 2 2 2 0 0 2 21 L6 2 2 4 0 0 0 0 1 1 0 2 2 2 0 2 18 L7 2 1 4 2 1 0 0 0 0 2 2 2 1 0 2 19 L8 2 2 4 0 1 2 2 0 2 1 2 2 2 0 2 24 L9 2 2 3 2 1 0 0 0 0 1 1 2 2 1 2 19 L10 2 2 4 0 1 2 2 2 2 2 2 2 1 2 2 28 L11 2 2 4 2 2 2 0 0 2 0 0 2 1 1 2 22 L12 1 2 2 0 1 0 0 0 0 1 1 1 1 1 2 13 L13 1 2 4 0 0 0 0 1 2 1 1 2 2 0 1 17 L14 1 0 4 2 0 0 0 0 2 2 2 2 0 1 0 16 L15 1 1 4 2 1 2 2 0 2 0 0 2 2 0 2 21 L16 2 1 4 0 1 0 0 0 0 0 0 2 1 0 2 13 L17 2 1 3 2 1 2 0 1 0 0 0 2 0 1 2 17 L18 2 2 4 2 1 2 2 0 2 0 2 1 1 1 1 23
L19 1 0 4 2 1 2 0 0 0 1 0 2 2 0 2 17
L20 2 2 4 0 2 0 0 2 2 2 2 2 2 1 2 25
L21 2 1 3 2 1 2 1 1 1 0 0 2 1 0 2 19
L22 2 0 4 2 1 1 2 1 2 0 0 2 0 0 2 19
Average 1.7 1.4 3.5 0.9 0.6 1 0.8 0.6 1.2 1 1.2 1.9 1 0.5 1.8 19.7
As indicated in Table 6 above, most questions were well-answered by the majority o f learners in the post-test. The total average marks scored by 22 learners was 19.7 out o f 32 marks, representing a 62% overall learners’ pass rate in the post-test.
Learners obtained average mark scores equal to 50% and greater than 50% in questions1, 2, 3, 6, 9, 10, 11, 12, 13 and 15. Although these questions were well-answered, the highest scores above 80% were recorded in the following questions: question 12 (95%), question 15 (90%), question 3 (87%) and question 1 (85%). In questions 1, 3, 12 and 15, learners were expected to choose the correct answers and then provide reasons for their choices. These questions were related to the identification o f coloured papers that reflect more light, reflections by plane mirror, images formed in the plane mirror, the law o f reflection o f light, refraction o f light and speed o f light in different mediums (Appendix H). Based on the learners’ responses from these questions, there was an indication that most learners were making sense when answering these questions.
The following are the samples o f 22 learners’ responses from question15 about the speed o f light (Appendix H).
Question 15:
L1 B) In a vacuum there are no air particles which broke the light.
L2 B) Because in a vaccum there is nothing to lock the air particles, is an empty space.
L3 B) In the vacuum there no particles, so there will be no any brokage o f light rays.
L 4 B) Because vacuum is the empty space without particles and the light can travel in fast.
L6 C) I have no valid reason why.
L8 A) Vaccum is a space where there is no any gases but light travel in place where there is oxygen and carbon dioxide.
L9 A) Because there are no particles.
L10 B) (Certain). Light are faster in the vaccum because vacuum is light conduct.
L11 A) (Almost certain). Because in the vacuum there are not particles inside to carry out light there.
L12 B) Light will travel faster in the vacuum because there are no particles in the vacuum and in the glass there is.
L13 A) Because light cannot pass through a vaccum.
L14 B) Light travel only in a vacuum like in air.
L15 B) It travels faster because the vacuum is an empty space with no particles that can decrease the speed o f light, so light faster in a vacuum.
L16 A) There is no particle to carry vibration.
L17 B) Because light can travel in any medium.
L18 B) Because in a vacuum there no air particles.
L19 B) Because light travel in a vaccum.
L20 B) Light travel faster in the vacuum only the sound can not travel in the vaccum.
L21 B) Because light travels with a higher speed since there are no other things.
L22 B) Vaccuum consist o f gas particles that are loosely arranged.
Although, 17 learners managed to choose option B (light travels faster in the vacuum) which is the correct answer, a few learners could not provide the correct explanation o f this choice.
Table 6 shows that learner 10 (L10), managed to score the highest total marks o f 28 out o f 32 (87.5%) while learner 12 (L12) and Learner 16 (L16) scored the lowest marks o f 13 out o f 32 (40.6%) pass rate. Table 6 also indicates that the following questions were poorly answered in the post-test: 4, 5,
7, 8 and 14, for which learners managed to score average marks below 50%. In these questions learners were expected to choose the correct answers in relation to the following: how the change in position o f the object in front o f the plane mirror affect its image in the mirror; how changing o f the location o f source o f light affects the height and size o f image o f the object in front o f the plane mirror; how the changing o f the distance o f the object in front o f the mirror affects the height o f its image in the plane mirror; and how a concave lens can be used to correct short-sightedness eye defect (Appendix H). Learners’ responses from these questions showed that they were struggling to make sense when answering these questions. Table 8 indicates that the lowest average marks scores o f 0.5 out o f 2, which represents 25% pass rate was recorded in question 14. It is evident that most learners do not know how the changing in position o f the object in front o f the plane mirror affects its image in the mirror.
The post-test results showed that learners had improved compared to the pre-test results. In the following section I present and discuss the specific individual change in scores for the two tests.