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Asia-Pacific Forum on Science Learning and Teaching, Volume 16, Issue 2, Article 2 (Dec., 2015) |
Table 4 presents the pre-service science teachers’ conceptual understanding of floating and sinking based on the subcategories of the test.
Table 4: The Pre-Service Science Teachers’ Understanding of Sinking and Floating
% Correct responses
Content area
DISF item
Only First tiers
Both two tiers
All three tiers
Scientific knowledge
Misconception
Lack of
confidenceLack of
knowledgeCategory1: Amount/level of liquid
1
65.7
63.3
55.9
55.9
25.9
7.4
10.6
2
70.5
67.9
57.5
57.5
21.4
10.3
10.6
11
79.3
72.1
62.5
62.5
14.5
9.5
13.2
20
76.9
71.6
58.3
58.3
12.2
13.2
16.18
Mean(%)
Factor1
73.1
68.7
58.5
58.5
18.5
10.1
12.6
Category2: Shape of objects
4
68.1
54.3
40.3
40.3
23.6
14
22.0
5
51.9
18.3
13.5
13.5
45.0
4.7
36.6
6
38.9
28.3
19.0
19.0
31.8
9.2
39.7
Mean (%)
Factor2
53.0
33.6
24.2
24.2
33.5
9.3
32.8
Category3: RFA
3
16.1
10.0
6.3
6.3
70.8
3.7
19.0
14
35.0
28.9
19.8
19.8
39.7
9.0
31.3
16
35.5
24.4
18.0
18.0
46.9
6.3
28.6
21
46.1
41.9
28.6
28.6
33.6
13.2
24.4
Mean (%)
Factor4
33.2
26.3
18.1
18.1
47.8
8.0
25.8
Category4: surface area/ position in liquid
7
70.0
64.9
54.1
54.1
19.0
10.8
15.9
8
61.2
51.9
41.1
41.1
29.7
10.8
18.3
Mean (%)
Factor6
65.6
58.4
47.6
47.6
24.4
10.8
17.1
Category5: Hard-soft
9
52.5
44.2
37.9
37.9
33.6
6.3
22.0
10
62.8
37.6
23.3
23.3
31.2
14.3
31.0
Mean (%)
Factor5
57.6
40.9
30.6
30.6
32.4
10.3
26.5
Category6: RDA
12
61.0
53.3
46.9
46.9
27.3
6.3
19.3
15
54.3
49.0
39.2
39.2
28.6
9.8
22.3
17
87.0
54.3
48.8
48.8
32.6
5.5
13.0
Mean (%)
Factor3
68.1
50.9
44.9
44.9
29.5
7.2
18.2
Category7: Pressure force
13
24.6
14.8
11.1
11.1
57.2
3.7
27.8
18
57.2
46.1
31.8
31.8
25.4
14.3
28.3
19
35.8
22.2
12.2
12.2
41.6
10.0
36.1
Mean (%)
Factor7
39.2
27.7
18.3
18.3
41.4
9.3
30.7
Table 5 shows the percentile values of 74 misconceptions that were grouped under seven categories.
Table 5. Percentage of misconceptions.
N=377 M1
M2
M3
M4
M5
M6
M7
M8
M9
M10
Mean
42
5.5
12.4
3.5
3
1.5
0.5
4
215
5
%
11.14
1.45
3.28
0.92
0.79
0.39
0.13
1.06
57.02
1.32
N=377
M11
M12
M13
M14
M15
M16
M17
M18
M19
M20
Mean
2
18
3
31
27
25
12
36
12
17
%
0.53
4.77
0.79
8.22
7.16
6.63
3.18
9.54
3.18
4.50
N=377
M21
M22
M23
M24
M25
M26
M27
M28
M29
M30
Mean
31
27
2
3,5
14
6
18
2
2
1
%
8.22
7.16
0.53
0.92
3.71
1.59
4.77
0.53
0.53
0.26
N=377
M31
M32
M33
M34
M35
M36
M37
M38
M439
M40
Mean
17
2
9
0,5
4
55
9
13
4
4
%
4.50
0.53
2.38
0.13
1.06
14.58
2.38
3.44
1.06
1.06
N=377
M41
M42
M43
M44
M45
M46
M47
M48
M49
M50
Mean
2
28
15
14
8
88
26
5
3
2
%
0.53
7.42
3.97
3.71
2.12
23.34
6.89
1.32
0.79
0.53
N=377
M51
M52
M53
M54
M55
M56
M57
M58
M59
M60
Mean
93
13
19
43
38
2
40
26
50
38
%
24.66
3.44
5.03
11.40
10.07
0.53
10.61
6.89
13.26
10.07
N=377
M61
M62
M63
M64
M65
M66
M67
M68
M69
M70
Mean
23
4
15
3
37
23
4
8
0
4
%
6.10
1.06
3.97
0.79
9.81
6.10
1.06
2.12
0
1.06
N=377
M71
M72
M73
M74
Mean
1
11
65
46
%
0.26
2.91
17.24
12.20
Graph 1 shows the graphic representation of the 74 misconceptions, which were based on the percentages in Table 5.
Graph1. Percentages of misconceptionsCategory1: Amount/Level of Liquid
The pre-service science teachers had the lowest levels of misconceptions in this category, as seen in Table 4. Except the misconception of M1 (11.14%), the other misconceptions are vanishingly small. The other misconceptions are M2 (1.45%), M3 (3.28%), M4 (0.92%), M5 (0.79%), M6 (0.39%), M7 (0.13%), and M8 (1.06%). Compared to the other studies in the literature, the percentiles in this category is relatively low. Unal and Costu (2005) demonstrated that 70% of the 8th-grade Turkish students had the misconception that the volume of the liquid would determine whether an object would float or sink. In addition, another study conducted by Unal (2008) confirmed this finding and found that 64% of the students in Turkey had the same misconception. Based on these findings, even though the majority of the 8th-grade students in Turkey had the misconception that the liquid amount/volume affects the buoyant force, this percentage was relatively lower for the pre-service science teachers. The percentage for lack of confidence (10.1%) was higher than 10%; this finding showed that the pre-service science teachers did not have enough confidence in their knowledge. However, the pre-service teachers had the highest percentage of scientific knowledge (58.5%) in this category. Furthermore, the pre-service teachers had the lowest percentages (12.6%) for lack of knowledge in this category.Table 6. The pre-service science teachers’ misconceptions related to the “amount/level of liquid” category
List of Misconceptions Three tier
M1.When the depth of a liquid increases, the magnitude of the buoyant force increases.
1.1.b, 1.2.b, 1.3.a
20.1.c, 20.2.e, 20.3.aM2.When the depth of a liquid decreases, the magnitude of the buoyant force increases.
1.1.a, 1.2.c, 1.3.a
20.1.b, 20.2.d, 20.3.aM3.When the amount of the liquid increases, the magnitude of the buoyant force increases/when the amount of the liquid decreases, the magnitude of the buoyant force decreases.
1.1.b, 1.2.d, 1.3.a
1.1.b, 1.2.e, 1.3.a
2.1.a, 2.2.a, 2.3.a
11.1.a, 11.2.a, 11.3.a
20.1.c, 20.2.a, 20.3.aM4.When the amount of the liquid increases, the magnitude of the buoyant force decreases.
2.1.b, 2.2.b, 2.3.a
20.1.b, 20.2.b, 20.3.aM5.When the volume of the liquid increases, the magnitude of the net pressure force increases, too.
2.1.a, 2.2.d, 2.3.a
2.1.b, 2.2.d, 2.3.a
11.1.c, 11.2.b, 11.3.aM6.When the volume of the liquid increases, the magnitude of the net pressure force decreases.
2.1.a, 2.2.e, 2.3.a
2.1.b, 2.2.e, 2.3.aM7.When the amount of the liquid increases, the density of the liquid decreases.
2.1.a, 2.2.f, 2.3.a
2.1.b, 2.2.f, 2.3.aM8.When the amount of the liquid increases, the density of the liquid increases.
2.1.a, 2.2.g, 2.3.a
2.1.b, 2.2.g, 2.3.a
11.1.a, 11.2.c, 11.3.aCategory 2: Shape of Objects
In contrast to Category 1, the pre-service science teachers had the highest lack of knowledge scores (32,8%) in this category. The pre-service science teachers’ levels of scientific knowledge were 24.2% while their lack of confidence percentage was 9.3%. The Turkish science curricula do not cover the topic of how the objects’ shapes affect their floating and sinking (MEB, 2006; MEB, 2013), and the college physics courses mostly cover the formulas. As a result, the pre-service science teachers have a low level of knowledge and a high level of misconceptions in this area. The pre-service science teachers’ level of misconception was 33.5%, which ranked third. Category 2 had 16 misconceptions. These misconceptions were predominantly related to mass, weight, volume, and change in density as well as the conformational changes that occur in a solid body. However, the pre-service teachers’ misconceptions in this category were less than 10%. The misconceptions held by more than 5% of the pre-service science teachers were M14 (8.22%), M15 (7.16%), M16 (6.63%), M18 (9.54%), M21 (8.22%), and M22 (7.16%). The misconceptions held by less than 5% of the pre-service science teachers were M12 (4.77%), M13 (0.79%), M17 (3.18%), M19 (3.18%), M20 (4.50%), M23 (0.53%), M24 (0.92%), and M25 (3.71%). The misconceptions that emerged in this study also were encountered in the following studies: Çepni et al. (2010); Çepni & Şahin (2012); Havu-Nuutinen(2005); Kang et al.(2005); Leuchter, Saalbach, & Hardy (2014); Moore, & Harrison(2004); Parker, & Heywood (2000); She (2002); Tao, Oliver, & Venville(2012); Unal & Costu (2005); and Yin, Tomita, & Shavelson (2008). However, some of these studies presented the findings in percentages.Parker and Heywood’s (2000) study is one of the studies that presented the misconceptions in percentiles. In their study, Post Graduate Certificate in Education (PGCE), when the students determined whether an object would sink or float, 75% of the students considered the shape of the object, 50% of them considered if an object had a hole, 43.2% of them considered whether an object was hollow, 59.1% of them considered the weight of the objects, and 2% of them considered the volume of the object. In She’s (2002) study, 15% of the students believed that the shape of an object determines whether the object would float or sink while 5% of the students claimed that boat-shaped objects float because they’re hollow, and solid objects would sink because of their weight. Moreover, Unal and Costu (2005) pointed out that when 8th-grade students decide whether an object would float or sink, 55% of the students consider the volume of the object, 47% of them consider the weight of the object, and 13% of them looked at the shape of the object. Also, in Unal and Costu’s (2005) study, 41% of the students had the misconception that if you made a hole through the object, it would sink. Even though the majority of the misconceptions in Category 2 were described in the literature, their percentiles were relatively low because the misconceptions were determined using the three-tier test. As the three-tier test measures the students’ responses at three level, the rate of misconceptions are lower than the studies that used different methods (Eryılmaz, 2010). Based on the results, RFA was the most common misconception held by the pre-service science teachers.
Table 7. The pre-service science teachers’ misconceptions related to the “shape of objects” category
List of Misconceptions
Three tier
M12.When two floating objects are combined as a block, the block sinks because of the increase in its mass.
4.1.b, 4.2.a, 4.3.a
M13.When two floating objects are combined as a block, the block sinks because of the increase in its volume.
4.1.b, 4.2.e, 4.3.a
4.1.b, 4.2.b, 4.3.aM14.When two floating objects (a portion above the liquid) with the same density are combined as a block, the block hangs in the liquid because of the increase in its density.
4.1.c, 4.2.d, 4.3.a
M15.If you make a hole through the solid object, it sinks because of filled liquid through the hole.
5.1.b, 5.2.a, 5.3.a
M16.If you make a hole through the solid object (a portion above the liquid), it will be hanging in the liquid because of the decrease in its volume.
5.1.c, 5.2.b, 5.3.a
M17.If you make a hole through the solid object (a portion above the liquid), it sinks because of the increase in its density.
5.1.b, 5.2,c, 5.3.a
M18.If you make a hole through the solid object (a portion above the liquid), the floating part in the liquid increases because of the decrease in its density.
5.1.a, 5.2.d, 5.3.a
M19.If you make a hole through the solid object (a portion above the liquid), the floating part (out of water) decreases because of the decrease in mass.
5.1.a, 5.2.f, 5.3.a
M20.If you make a hole through the solid object (a portion above the liquid), the floating part (out of water) increases because of the decrease in volume.
5.1.a, 5.2.g, 5.3.a
M21.When the objects are carved from the upper part, they float because of the decrease in density.
6.1.a, 6.2.a, 6.3.a
M22.When the solid object (a portion above the liquid) are carved from the upper part, they hang in the liquid because of the decrease in mass.
6.1.c, 6.2.b, 6.3.a
M23.When the solid object (a portion above the liquid) are carved from the upper part, they sink because of the increase in density.
6.1.b, 6.2.c, 6.3.a
M24.The surface area of the carved objects increase, so does the magnitude of the buoyant force.
6.1.a, 6.2.e, 6.3.a
6.1.c, 6.2.e, 6.3.aM25.A carved object will be filled with air, so it will float.
6.1.a, 6.2.f, 6.3.a
Category3: RFA
The pre-service science teachers got the highest level of misconception (47.8%) in this category. M9 (57.02) was the highest level of misconception about the magnitude of the buoyant force of the hanging objects and weight, which was quite high when compared to the other misconceptions in this category. The other misconceptions with the highest levels of percentages were M59 (13.26%), M60 (10.02%), M61 (6.10%), M73 (17.24%), and M74 (12.20%). In Unal and Costu’s (2005) study, they found that 26% of the 8th-grade students thought that when two objects at the same mass were put into a liquid, the buoyancy of the object hanging in the liquid is more than that of the floating object. 54% of them believed that when the density of the liquid increased, the buoyant force would increase, too. Both the pre-service science teachers and the 8th-grade students had the misconception about the buoyancy of the floating objects and the objects hanging in a liquid. The other misconception in this category was about the principle of Archimedes.The RFA category included the questions related to the principle of Archimedes. More than 10% of the pre-service science teachers had the misconceptions of M54 (11.40%) and M55 (10.07%), which were related to the weight of the objects, the weight of the overflowing liquid, and the magnitude of the buoyant force. Unal and Costu (2005) indicated that 41% of the 8th-grade students held the misconception that the magnitude of the buoyant force of an object hanging in a liquid was more than the magnitude of the weight of the liquid overflowing. The other misconceptions related to RFA were M10 (1.32%), M11 (0.53%), M56 (0.53%), and M72 (2.91%). Especially, the pre-service science teachers confused RFA with RDA when interpreting the magnitude of the buoyant force of a floating object. Apaydin (2014) found that the 8th-grade students not only confused the concepts of RDA with RFA, which were defined in this study, but they were also not aware of the forces’ impact on the floating or sinking objects. In addition, Unal and Costu (2005) pointed out that 19% of the 8th-grade students in Turkey considered the density as a force exerted on the object from the bottom. This study confirmed these findings: the pre-service science teachers held misconceptions like the 8th-grade students in Turkey.
The pre-service teachers had the highest levels of misconceptions, the lowest levels of scientific knowledge (18.1%), and quite high lack of knowledge scores (25.8%) as RFA was one of the hardest topics that the pre-service science teachers had trouble with. However, the pre-service teachers reported high lack of confidence scores (8%). This finding showed that the pre-service teachers’ high level of confidence led them to have high levels of misconceptions. Contrariwise, the pre-service science teachers got high lack of confidence scores in Category 4.
Table 8. The pre-service science teachers’ misconceptions related to the “RFA (relative force approach) category
List of Misconceptions
Three tier
M9. When the density of a liquid increases, the magnitude of the buoyant force that acts on a hanging object in a liquid increases.
3.1.a, 3.2.b, 3.3.a
M10.When the density of a liquid increases, the magnitude of the buoyant force that acts on a hanging object in a liquid decreases.
3.1.b, 3.2.a, 3.3.a
M11.When the pressure increases, the magnitude of the buoyant force decreases; when the pressure decreases, the magnitude of the buoyant force increases.
3.1.b,3 .2.d, 3.3.a
3.1.a, 3.2.e, 3.3. aM54.When two different liquids overflow from the overflowing container, the one with bigger volume always weighs more.
14.1.b, 14.2.a, 14.3.a
M55.When two different liquids overflow from the overflowing container, the one with bigger density always weighs more.
14.1.a, 14.2.b, 14.3.a
M56. The weight of the liquid that is overflown by a floating object that has less submerged portion is less than the amount of the liquid that has more submerged portion in the liquid.
14.1.a, 14.2.d, 14.3.a
M59.When two objects float in the same liquid, the object that is close to the bottom will be affected by more buoyant force.
16.1.c,16.2.a,16.3.a
M60.When two objects with an equal mass float in a liquid, the magnitude of the buoyant force of the one that is closer to the bottom is less than the magnitude of the buoyant force of the other one.
16.1.a, 16.2.b, 16.3.a
M61.When two objects with equal mass float in a liquid, the magnitude of the buoyant force of the one that floats (out of water or a portion above the liquid) is more than the magnitude of the buoyant force of the one that hang in the liquid.
16.1.a,16.2.c, 16.3.a
M72.A floating object’s weight is more than the buoyancy of the object.
21.1.c, 23.2.a, 23.3.a
M73.The weight of a sinking object is less than the buoyancy of the floating object.
21.1.b, 23.2.b, 23.3.a
M74.A floating object’s buoyant force is greater than the object’s weight.
21.1.b, 23.2.d, 23.3.a
Category 4: Surface Area and Position in Liquid
The pre-service science teachers got the highest lack of confidence scores (10.8%) in this category. This topic is not part of the science curriculum (MEB, 2006; MEB, 2013); the pre-service science teachers may not feel confident in their answers as they encountered the content for the first time. Besides, the findings showed that the pre-service science teachers used their scientific knowledge to answer the questions in this category. The pre-service teachers had quite high levels of scientific knowledge (47.6%), and they got quite high lack of knowledge scores (17.1%) and low levels of misconceptions (24.4%), compared to the other areas. In this category, the pre-service teachers had the second-lowest levels of misconceptions. The pre-service teachers’ misconceptions were M26 (1.59%), M27 (4.77%), M28 (0.53%), M29 (0.53%), M30 (0.26%), M31 (4.50%), M32 (0.53%), M33 (2.38%), M34 (0.13%), and M35 (1.06%). Even though the pre-service teachers had all these misconceptions, the percentages for each misconception were low. Parker and Heywood (2000) found that 11.4% of the PGCE students had misconceptions about how an object is placed; 72.7% of them had the misconception that the buoyant force that acts on the objects’ surface would affect whether an object sinks or floats. The results of a study conducted by She (2002) showed that 25% of the students had the misconception that if the contact surface area of the object with water increases, the magnitude of the buoyant force would decrease. She (2002) also determined the misconception of M35 in this study. However, only 1.06% of the pre-service science teachers held this misconception. Similar to Category 4, the pre-service science teachers had high lack of confidence scores in the soft- and hard-object topic.Table 9. The pre-service science teachers’ misconceptions related to the “Surface area and position in liquid” category
List of Misconceptions Three tier
M26.The sharp edge of an object makes it sink.
7.1.b, 7.2.a, 7.3.a
M27. The magnitude of the buoyant force of a sharp edge of an object is less than that of a flat object.
7.1.b, 7.2.b, 7.3.a
M.28.When the flat surface of a cone-shaped floating object (out of water) is flipped horizontally, the object sinks because of the increase in the floating part in the liquid.
7.1.b, 7.2.f, 7.3.a
M.29.When the flat surface of a cone-shaped floating object (out of water) is flipped horizontally, the object floats because of the increase in the object’s density.
7.1.c, 7.2.e, 7.3.a
M.30.When the flat surface of a cone-shaped floating object (out of water) is flipped horizontally, the object sinks because of the increase in the volume of sinking part.
7.1.b, 7.2.c, 7.3.a
M31.When an object is dropped off in a liquid vertically, the magnitude of the buoyant force of the object is bigger than when the object is dropped off horizontally.
8.1.a, 8.2.a, 8.3.a
M32.When an object is dropped off in a liquid vertically, the magnitude of the buoyant force of the object will be less than when the object is dropped off in horizontally.
8.1.b, 8.2.b, 8.3.a
M33.When a horizontal object is dropped off liquid vertically, the object does not sink because they apply less pressure.
8.1.a, 8.2.c, 8.3.a
8.1.c, 8.2.c, 8.3.aM34.When a horizontal object is dropped off in a liquid vertically, the object’s density decreases.
8.1.a, 8.2.e, 8.3.a
8.1.c, 8.2.e, 8.3.aM35.When an object is dropped in water horizontally, it will sink; when the object is dropped vertically, it will float because dropping vertically increases its volume.
8.1.a, 8.2.f, 8.3.a
8.1.c, 8.2.f, 8.3.aCategory 5: Hard and Soft Objects
The pre-service science teachers’ lack of confidence percentage was 10.3% in this category. Like Category 4, this topic is not a part of science curricula. Therefore, the pre-service science teachers may not feel confident when they are answering the questions because they are not familiar with the topic. The pre-service science teachers’ levels of scientific knowledge were 30.6%, their lack-of-knowledge scores were 26.5%, and their levels of misconceptions were 32.4%. M36 (14.58%) and M46 (23.34%) were the two highest levels of misconceptions held by the pre-service science teachers in this category. M42 (7.42%) was the third-highest levels of misconception, which was that putting the soft objects on the top of the hard objects increases the buoyant force. The other misconceptions in Category 5 were M37 (2.38%), M38 (3.44%), M39 (1.06%), M40 (1.06%), M41 (0.53%), M43 (3.97%), M44 (3.71%), and M45 (2.12%). According to the studies, the 8th-grade students believed that the soft objects would float and the rigid objects would sink (Moore & Harrison, 2004; Yin, Tomita, & Shavelson, 2014). In addition, the misconception that the soft objects would sink was more common than the misconception that the rigid objects would sink. The pre-service science teachers had lower levels of confidence in Category 6 than Category 4 and Category 5.Table 10. The pre-service science teachers’ misconceptions related to the “Hard & soft objects” category
List of Misconceptions
Three tier
M36.Soft objects float out of water or a portion above the liquid.
9.1.a, 9.2.a, 9.3.a
M37.Soft objects would hang in a liquid.
9.1.c, 9.2.b, 9.3.a
M38.The hard objects sink because their density is higher than the soft objects.
9.1.a, 9.2.c, 9.3.a
M39.Soft objects sink because of their density.
9.1.b, 9.2.d, 9.3.a
M40.The magnitude of the soft objects’ buoyant force is greater than the hard objects.
9.1.a, 9.2.f, 9.3.a
9.1.c, 9.2.f, 9.3.aM41.The magnitude of the soft objects’ pressure force is more than the hard objects’ pressure force.
9.1.a, 9.2.g, 9.3.a
9.1.c, 9.2.g, 9.3.aM42. When the soft objects are added to the floating hard objects in a closed container, the closed container sinks because the magnitude of the buoyant force decreases.
10.1.b, 10.2.a, 10.3.a
M43.When the soft objects are added to the floating hard objects in a closed container, the density of the closed container decreases, so the closed container floats.
10.1.a, 10.2.b, 10.3.a
10.1.c, 10.2.b, 10.3.aM44.When the soft objects are added to the sinking hard objects in a closed container, the closed container floats because of the increased the magnitude of the closed container’s buoyant force.
10.1.a, 10.2.c, 10.3.a
10.1.c, 10.2.c, 10.3.aM45.When the soft objects are added to the sinking hard objects in a closed container, the volume of the closed container increases, so the object floats.
10.1.a, 10.2.d, 10.3.a
10.1.c, 10.2.d, 10.3.aM46.When the soft objects are added to the floating hard objects in a closed container, the density of the closed container increases, so the closed container sinks.
10.1.b, 10.2.e, 10.3.a
Category 6: RDA
Compared to the other categories, this category ranks in the middle in terms of levels of scientific knowledge (44.9%), lack of knowledge scores (18.2%), and levels of misconceptions (29.5%). The RDA category included nine different misconceptions. The highest levels of misconceptions that the pre-service teachers held were M57 (10.61%), M47 (6.89%), and M58 (6.89%). The other misconceptions held by less than 5% of the pre-service teachers were M48 (1.32%), M49 (6.89%), M50 (0.53%), M62 (1.06%), M63 (3.97%), and M64 (0.79%).
The pre-service teachers reported the lowest lack of confidence scores (7.2%) in this category. Almost all science curricula and the textbooks that were written based on them include a section on RDA. The students may feel comfortable when answering the RDA questions as they come across with it quite often (Yin et al, 2014).When making a decision about whether an object floats or sinks, compared to RFA (where students compare forces), the pre-service science teachers had fewer misconceptions about RDA (where students compare density). Even though this topic was a part of all science curricula, the pre-service science teachers had quite high levels of misconceptions. Because the students used rote memorization for RDA instead of in-depth thinking (Yin et al., 2014), they treated RDA as density and made decisions by only looking either at the object’s density or the liquid’s density. She (2002) claimed that 5% of the students made a decision about whether a can would float or sink based on the water’s density. In addition, the students had misconceptions related to comparing the density of objects and liquids.
Unal and Costu (2005) found that 8% of the 8th-grade students had the misconception that the density of a hanging object is equal to the density of a floating object, and 6% of them held the misconception that the density of a hanging object is equal to the density of a sinking object. In the same study, 45% of the students had the misconception that the density of a floating object is more than that of a sinking object and an object hanging in a liquid. 6% of the students had the misconception that the density of an object hanging in a liquid is less than the density of the liquid.Table 11. The pre-service science teachers’ misconceptions related to the “RDA (relative density approach)” category
List of Misconceptions
Three tier
M47.When comparing two liquids with different densities, the buoyancy of the one with low density will be more.
12.1.a, 12.2.a, 12.3.a
15.1.b, 15.2.d, 15.3.aM48.Only an object’s density determines if the object floats or sinks.
12.1.c, 12.2.b, 12.3.a
M49.When compared to two liquids with different densities, the magnitude of the pressure force of one with low density will be more.
12.1.a, 12.2.d, 12.3.a
12.1.c, 12.2.d, 12.3.aM50.The buoyancy of an object is not related to the liquid’s density.
12.1.c, 12.2.e, 12.3.a
M57.The density of the liquid does not affect the buoyancy of the sinking objects.
15.1.a, 15.2.a, 15.3.a
M58. Despite the density of the liquid, the buoyant force remains the same for all sinking objects.
15.1.a, 15.2.c, 15.3.a
M62.Objects that are covered by the liquid have always the same density.
17.1.a, 17.2.c, 17.3.a
M63.The objects with low density have more buoyant force.
17.1.b, 17.2.d, 17.3.a
M64.When an object has a bigger volume, they float because they also have big density.
17.1.c, 17.2.e, 17.3.a
Category 7: Pressure Force
The pre-service science teachers had high levels of misconceptions in this category. The pre-service science teachers had the second-highest levels of misconceptions (41.4%) and the second-lowest levels of scientific knowledge (18.3%) after RFA. The pre-service science teachers’ lack of knowledge level was 30.7%, and lack of confidence level was 9.3%. In this study, M51 (24.66%) was the second-highest levels of misconception held by the pre-service teacher M9. The other highest levels of misconceptions were M53 (5.03%), M65 (9.81%), and M66 (6.10%). The other misconceptions that were less than 5% were M52 (3.44%), M67 (1.06%), M68 (2.12%), M70 (1.06%), and M71 (0.26%). Besson (2004) in his study asked the students a hanging fish’s pressure in the open sea and the pressure of a fish hanging in a cave at the bottom of the sea at the same elevation. 25% of the college students held the belief that the pressure in the open sea would be greater than the cave while 8% of them believed that the pressure in a cave would be greater. Considering the students’ misconceptions about the pressure, the students may have misconceptions related to sinking and floating and pressure force. Besides, 12% of the students in Besson’s study were aware that the buoyant force is a result of the pressure forces. These findings verify that the pressure force is a difficult subject for students.Table 12. The pre-service science teachers’ misconceptions related to the “pressure force” category
List of Misconceptions Three Tier
M51.The magnitude of the pressure forces that acts on a hanging object in a liquid would be same.
13.1.c, 13.2.a, 13.3.a
13.1.c, 13.2.e, 13.3.a
19.1.c, 19.2.a, 19.3.a
19.1.c, 19.2.d, 19.3.aM52.The magnitude of the pressure force from the top of an object hanging in a liquid is more than the magnitude of the pressure force from the bottom.
13.1.a, 13.2.b, 13.3.a
13.1.a, 13.2.f, 13.3.a
19.1.a, 19.2.e, 19.3.aM53.The magnitude of the pressure force from the bottom of an object hanging in a liquid is more than the magnitude of the pressure force from the top of the object because the object’s weight and the object’ buoyant force affect the bottom of the object.
13.1.b, 13.2.d, 13.3.a
M65.When the amount of the liquid is more on a floating object, the magnitude of the pressure force is more, too.
18.1.a, 18.2.a, 18.3.a
M66.Because of the weight of both rocks and water, the magnitude of the pressure force of a fish that is located in a cave under a sea is more than the pressure force of a fish that floats in an open sea under same depth.
18.1.b, 18.2.c, 18.3.a
M67. When two identical objects are put into liquid, the one with more liquid at the top of the object has the greater magnitude of the pressure forces than the one with less liquid at the top of the object
18.1.a, 18.2.d, 18.3.a
M68.The buoyant force does not impact the objects hanging in a liquid.
18.1.c, 18.2.e, 18.3.a
M69.Because the density of water in a cave under the sea is less than the density of water in the open sea, the magnitude of the pressure force impacts a fish in a cave undersea is less, too.
18.1.a, 18.2.f, 18.3.a
M70.The magnitude of the pressure force of a floating object acting on the upper part is more than the magnitude of the pressure force acting on the bottom part because the weight of water above is less.
19.1.a, 19.2.b, 19.3.a
M71.Because the pressure force and the weight direction are reversed, the magnitude of the pressure force acting on the bottom is less than the upper.
19.1.a, 19.2.c, 19.3.a
