Teaching floating and sinking concepts with different methods and techniques based on the 5E instructional model

Data was collected from three open-ended questions and presented under the title “Quantitative Data” and “Qualitative Data.” The flow chart of the data is given below (Figure 2).

fig2

Figure 2. Flowing chart of the data

Quantitative data

The Mann Whitney U pretest results (Table IV) and Mann Whitney U posttest results were introduced (Table V).

Table IV. Mann Whitney U pretest results

Group	N	Mean Rank	Sum of Rank	U	p
Experiment	25	24.96	624.00	276.000	0.812
Control	23	24.00	552.00

As can be seen from Table IV (U=276.000, p> 0.05), there is no significant difference between the EG and CG according to the pretest. The averages ordered of the EG and CG are closer to each other [E (24.96); C (24.00)].

Table V. Mann Whitney U posttest results

Group	N	Mean Rank	Sum of Ranks	U	p
Experiment	25	30.86	771.50	128.500	0.001
Control	23	17.59	404.50

As can be seen from Table V (U=128.500, p < 0.05), there is a significant difference between the EG and the CG according to posttest. The EG and the CG average order has a significant difference in favor of EG [E (30.86), C (17.59)].

Table VI. Mann Whitney U delayed post-test results

Group	N	Mean Rank	Sum of Ranks	U	p
Experiment	25	33.06	826.00	73.500	0.000
Control	23	15.20	349.00

As can be seen from Table VI (U=73.500, p < 0.05), there is a significant difference between the EG and CG according to delayed posttest. The EG and CG average order has a significant difference in favor of EG [E (33.06), C (15.20)].

In this section, Wilcoxon Signed Ranked Test results covering the CG (Table VII) and EG (Table IX) were presented.

Table VII. Comparison of the CG Wilcoxon Signed Rank posttest and pretest

Posttest- Pretest	N	Mean rank	Sum of Ranks	z	p
Negative Rank	10	9.80	98.00	-.262	.793
Positive Rank	10	11.20	112.00
Ties	3

* Based on negative order

As seen from Table VII (z= -.262, p> 0.05), there is no significant difference in favor of pre and posttest for the CG. When Table VII is examined, 10 students’ pretest scores are higher than their posttest scores in the CG. Ten students’ posttest scores are higher than their pretest scores. It is also seen that 3 student’s pretest and posttest scores remained the same.

Table VIII. Comparison of the CG with Wilcoxon Signed Rank delayed posttest and posttest

Delayed posttest- Posttest	N	Mean Rank	Sum of Ranks	z	p
Negative Ranks	15	11.77	176.50	-1.625	.104
Positive Ranks	7	10.93	76.50
Ties	1

As it is seen in Table VIII (z= -1.625, p> .05), there is no a significant difference in favor of delayed posttest and posttest for the CG. When Table VIII is examined it is seen that 15 students’ posttest scores are higher than their delayed posttest scores in the CG. Seven students’ delayed posttest scores are higher than their posttest scores. It is also seen that 1 student’s delayed posttest and posttest scores are same.

Table IX. Comparison of the EG with Wilcoxon Signed Rank posttest and pretest

Posttest - Pretest	N	Mean Rank	Sum of Ranks	z	p
Negative Ranks	3	5.17	15.50	-3.844	.000
Positive Ranks	21	13.55	284.50
Ties	1

* Based on negative order

As it is seen in Table IX (z= -3.844, p< .000), there is a significant difference in favor of the posttest for the EG. When Table IX is examined it is seen that 3 students’ pretest scores are higher than their posttest scores in the EG. Twenty-one students’ posttest scores are higher than their pretest scores. It is also seen that 1 student’s pretest and posttest scores are same.

Table X. Comparison of the EG with Wilcoxon Signed Rank posttest anad delayed posttest

Delayed Posttest - Posttest	N	Mean Rank	Sum of Ranks	z	p
Negative Ranks	9	12.22	110.00	-.537	.592
Positive Ranks	13	11.00	143.00
Ties	3

* Based on negative order

As it is seen in Table X (z= -.537, p> .000), there is no a significant difference in favor of the delayed posttest and posttest for the EG. When Table X is examined it is seen that 13 students’ delayed posttest scores are higher than their posttest scores in the EG. Nine students’ posttest scores are higher than their delayed posttest scores. It is also seen that 3 students’ delayed posttest and posttest scores are same.

Qualitative data

In this section, students’ answers in pretest, posttest and delayed posttest are compared and given as figures.

Question 1:

I. A marble with 50 gr mass

II. A tray with 1000 gr mass

III. A square shaped bell jar with 100 gr mass

If we put the substances above into water, which one of the following is absolutely true about floating and sinking situations in water?

a) The tray with 1000gr mass sinks.

b) The square shaped bell jar with 100 gr mass floats.

c) The marble with 50 gr mass floats.

d) Nothing can be said about floating and sinking situation of substances in water.

* * It represents the correct answer of the question

Because: ……………………………………………………………

………………………………………………………………………

graph1

Graph 1. Students’ pretest, posttest and delayed posttest results for question 1

When Graph 1 is examined it is seen that 24% of the EG and 30% of the CG students are in IC-RIAC category. In the pretest, 16% of the EG and 21% of the CG students are in the CC-CR category. 75% of the EG students who have alternative concepts in the pretest remove them in posttest and moved to CC-CR category. None of the students in CG having alternative concept in pretest could move to CC-CR category in posttest. Only one of the students in the CG moved from the CC-RIAC to the CC-PCR category. When delayed posttest scores are examined, 56% of the EG and 8% of the CG students are in the CC-CR category. Figure 1 shows that the students from the EG, numbered E1, E13, E23 and E24, have alternative conceptions in pretest; then they removed their alternative concepts and moved to the CC-CR category in the delayed-posttest. In the pretest, E13 said, “There is air inside of a bell jar; this air applies buoyancy force to the bell jar.” In the delayed posttest, E13 removed the alternative conception and marked the choice “nothing can be said about floating and sinking situation of substances in water” and said, “Substances density should be given.” E3 has an alternative conception in the pretest that the “mass of [a] tray is more than mass of water so it sinks.” Then E3 moved to the CC-CR category in the posttest but turned back to the alternative conception at the delayed posttest. E3 said, “It is not possible to say something since the mass of water is not given.” None of the CG students that had alternative cocncepts in the pretest moved to the CC-CR category at delayed posttest. Students C8, C15, C18 and C20 had alternative conceptions in the pretest and they remained during the delayed posttest. C4, C6, C13 and C23 students had alternative conceptions in pretest, and then in delayed posttest they choose the correct choice, but could not explain any reasons for their choices. C14 is in CC-CR category in pretest and explains his reason as the “Density of these objects could not be known. To know the density of these objects also their volumes should be given.” But in delayed posttest C14 moved to IC-RIAC category and explained the reason by saying, “As the mass of tray is more, it sinks.”

Question 2: When a student puts an egg into water it sinks. What should the student do for the egg to float in the water?

a) Add water into the container

b) Solve a very big amount of salt in water*

c) Add olive oil into the water

d) Vaporize some of the water

Because: ………………………………………………………………………………

………………………………………………..……………………………

graph2

Graph 2. Students’ pretest, posttest and delayed posttest results for question 2

When Graph 2 is examined it is seen that eight students from the EG and eight students from the CG are in the IC-RIAC category. Although in the EG 4 students passed from the IC-RIAC category to the CC-CR category in posttest, but none of the students in this category are in the CG. EG students have misconceptions in the pretest also pass to the CC-PCR category in posttest. When the EG and CG students delayed posttest results are examined, it is seen that eight students are in the CC-CR; fourteen students are in the CC-PCR category from the EG, two students are in the CC-CR category and 7 students are in the CC-PCR category from the CG. When we examined Figure 2, we saw that students from the EG numbered E3, E6, E13, E17, E18, E20 and E23 have alternative conceptions in pretest then they removed their alternative concepts and moved to the CC-CR category in delayed posttest. In the pretest, E3 said “The mass of a sinked egg is more than the mass of water. When water is added the mass of the egg becomes less than the mass of water so it floats.” She removed her alternative concept in delayed posttest and said, "When we add salt, the density of the water increases so buoyancy force also increases.” C5, C6, C9, C13, C15, C18, C20 and C23 students from CG have alternative conceptions in pretest, only C13 codded student has an alternative concept in pretest finally moved to the CC-CR category in the delayed posttest. The C2 coded student is in the CC-PCR category in both the pretest and posttest, but moved to IC-RIAC category in the delayed posttest. She explained her reason as “When oil is going to the top of water it can hold it.” C18 coded student has an alternative concept of “when we put water it floats” in the pretest and could not remove his alternative concept in delayed posttest, too.

Question 3: In the figure, objects numbered 1, 2, 3 and 4 are in a balance in the water. Accordingly which statements given below are correct?

I. Just the object numbered 4 is floating in water.

II. Objects numbered 1, 2 and 3 are sinking in water.

III. Objects numbered 2, 3 and 4 are floating in water.

a) Only I b) I and II c) Only III * d) I, II and III

Because: ………………………………………………………………………………

………………………………………………..……………………………

graph3

Graph 3. Students’ pretest, posttest and delayed posttest results for question 3

When Graph 3 is examined it has seen that eight EG students in pretest are in the IC-RIAC category and four CG students are in the IC-RIAC category in pretest. In posttest, only three students from the IC-RIAC category had a conceptual change and passed through to the CC-CR category. Eight students from the EG and 2 students from the CG pass through to the CC-CR category in delayed posttest. When we examined Figure 3, we saw that students from the EG numbered E8, E16, E17 and E21 have alternative conceptions in the pretest, and then they removed their alternative concepts and moved to the CC-CR category in the delayed posttest. E12, E16, E17, E21, E22 and E25 assess being under water as sinking in the pretest. E16 and E17 continued this idea in posttest, but in delayed posttest they removed their alternative conception and moved to the CC-CR category. E12 and E22 continued to have their alternative conceptions through the pretest and delayed posttest. E12 explained his idea as “2, 3 and 4 float in water, and water applies buoyancy force on them.” She thought that buoyancy force does not effect sinking objects. None of the CG students that had alternative conceptions in pretest moved to the CC-CR category in delayed posttest. Although student C15 was in the CC-CR category and did not have any alternative conceptions in pretest, the student moved to the IC-RIAC category in delayed posttest. She explained her reason as, “Object number 4 is floating above the water. Objects numbered 1, 2 and 3 are inside of the water so they sink.” Students coded C13, C20 and C21 had an alternative conception in the pretest and in the delayed posttest, too.