west kalimantan students' conceptions about sound

8/14/2019 West Kalimantan Students' Conceptions About Sound

1/27

STUDENTS' CONCEPTIONS OF THE

PHYSICS OF SOUND

Leo SutrisnoDept. Math and ScienceEducation

Faculty of Education

Tanjungpura UniversityPontianak, Indonesia

List of contents

1 sample characteristics2 Students' conceptions of sound2.1 Results in general2.2 The generation of sound (DPH1)2.3 The transmission of sound (DPH2)2.4 The medium of transmission (DPH3)2.5 Velocity of sound and velocity of light (DPH4)2.6 The velocity of sound in gases (DPH5)2.7 The velocity of sound in solids (DPH6)2.8 The velocity of sound in liquids (DPH7)2.9 Pitch (DPH8)2.10 The Doppler effect (DPH9)2.11 Amplitude and loudness (DPH10)2.12 Wave length and tone (DPH11)2.13 Resonance (OPH12)2.14 Beat (DPH13)2.15 The human ear (DPH14)2.16 The night phenomenon of the transmission of sound (DPH15)2.17 The effect of the gravitational force on sound (DPH16)3 Comparison the first and second investigations4 Focuses of remedial work

52


2/27

List of tables

Table 1 Frequency distribution of students in each school

Table 2 Frequency distribution of total scores of physics

diagnostic test

Table 3 Percentages of students tested after formal

instruction in the physics of sound who held

conceptions which differed from scientists'

conceptions

Table 4 Number and percentages of students

who mastered and who did not master

each sub-unit

1 sample characteristics

In order to establish the foundation for remediationthroughout Kalimantan Barat, it would be better to have

information as large as possible. Therefore, this diagnostic test

was administrated among 596 students enrolled in 19 Senior

High Schools.

This investigation involved the administration of the final

form of the physics diagnostic test, both as a trial for the test andto establish some norms or expectations for the performance of

53


3/27

second year SMA students (roughly equivalent to year 11 in

Australian schools) after having received formal instruction on the

physics of sound. The students' conceptions about sound will be

presented and will be compared with scientists' conceptions.Students' conceptions which urgently need to be remedied will be

identified.

Nineteen schools were randomly chosen as the sample. Ten

SMAs are in the Pontianak municipality, four are in the Pontianak

regency, two are in Sambas and three in Sanggao regencies.

These nineteen SMAs are distributed in the towns of Pontianak,Mempawah, Singkawang, Pemangkat, Pahouman, Ngabang,

Sangau and Sekadau. The average distance from Pontianak, the

provincial capital, is about 183 km. The total number of students

who participated in this second investigation was 596.

Table 5.1 shows the distribution of students' ethnicity based

on their fathers' ethnic backgrounds. The Chinese studentsgroup is the largest (35.1%), followed by Malay (26%),

Dayaknese (16.1%)Javanese (14.9%). There are other small

groups such as Sundanese (2.2%); Sumantrans, either

Padangnese or Bataknese (2.4%), Sulawesians, either Bugese or

Manadonese (2.7%) and other (0.6%). There are 391 (65.6%)

male students and 205 (34.4%) female students who participatedin the investigation.

Table 1 Frequency distribution of students in each school

School Frequency Percent

SMAN1 PTK 45 7.6

54


4/27

SMAN2 PTK 25 4.2SMAN5 PTK 34 5.7SMAN6 PTK 24 4.0SMAN7 MPW 38 6.4SMAN8 PTK 42 7.0SMAN1 SKW 40 6.7SMAN MPW 26 4.4SMAN NGB 23 3.9SMAN SGO 40 6.7SMAN SKD 34 5.7SMA St. Paulus 34 5.7SMA F. Asisi 25 4.2SMA Islamiah 45 7.6

SMA A. Wacana 26 4.4SMA Kandayan 31 5.2SMA S. Pranoto 30 5.0SMA S SKW 18 3.0

SMA S SGO 16 2.7

Total 596 100.0

The students' characteristics, recorded individually, are prior

achievement in physics (PHACH), prior achievement in

mathematics (MTACH), prior achievement in language

(Indonesian) (INACH), ranking of the overall achievement in the

previous semester (Rank), verbal analogy ability (AVAB), and

mathematical reasoning ability (MTRSN). They were labelled for

purposes of computer analysis. On a scale of 0 - 10 the mean of

PHACH is 6.51 (Sd = 0.65); MTACH is 6.67 (Sd = 0.84) and INACH

is 6.82 (Sd = 0.68). These measures of prior achievement were

based on the school-reports in the previous semester. It can be

argued that these >cores might vary somewhat from one school

to another. Scheffe tests indicate three, six and no pairs out of

171 pairs are significantly iifferent at .O1 level for PHACH, MTACH

55


5/27

and INACH respectively, and .00 the scores from different schools

can be regarded as comparable.

To make the data comparable students of this school were

asked their total scores according to school reports, and theinvestigator then ranked these total sum scores as the other

schools did. On ranks from 1 to 30, the average rank is 12.58 (SD

= 8.15). Scheffe test results reveal no significant difference

among these schools at the .O1 level.

The last two aspects of students' characteristics, the verbal

analogy and the mathematical reasoning ability, were detected byadministering tests. The verbal analogy scores ranged from 19 to

30 points out of 30 points. The average was 26.40 with 2.05

standard deviation. The mathematical reasoning ability was

focused on the ability to transform verbal sentences into

mathematical sentences. On a scale of 0 - 10 the average score

was 8.16 (Sd = 1.76).

2 Students' conceptions of sound

2.1 Results in general

As has been mentioned in Chapter 4, the physics diagnostic

test consisted of 32 items which were divided into several

concepts of sound: sources of sound (DPH1), the transmission of

sound (OPH2), the medium of transmission (OPH3), velocity of

sound vs velocity of light (DPH4), the velocity of sound in gases

56


6/27

(DPH5), the velocity of sound in solids (DPH6), the velocity of

sound in liquids (DPH7), pitch (DPH8), the Doppler Effect (OPH9),

amplitude vs loudness (DPH10), wave length vs tone (DPH11),

resonance (DPH12), beat (DPH13), human ears (DPH14), the nightphenomenon of sound (DPH15), and the influence of the

gravitational force (OPH16). DPH3 - 7,9 were tested by three

items each. DPH1 - 2,8,14 were tested by two items each. For

mastery, students should have answered two questions in each

concept correctly. DPH10 - 13,15,16 had only one item each. Thus

the maximum score for this test was 16. The total score of this )hysics diagnostic test, for the purpose of identification in the

computer computation, is labelled as DPTL.

Scores resulting from this investigation ranged from 2 to 16

with mean and standard deviation of 8.22 and 2.95 respectively.

The distribution of these scores is presented in Table 5.2. The

coefficient of skewness (.13) indicates that scores areapproximately normally distributed and are peaked around the

mean (coefficient of kurtosis = 2.67).

Table 2 Frequency distribution of total scores of physics

diagnostic test

Score Frequency PercentCum.

Percent

0 2 .3 .31 3 .5 .82 6 1.0 1.8

57


7/27

3 15 2.5 4.44 29 4.9 9.25 53 8.9 18.16 68 11.4 29.57 78 13.1 42.6

8 81 13.6 56.29 71 11.9 68.110 54 9.1 77.211 46 7.7 84.912 39 6.5 91.413 25 4.2 95.614 17 2.9 98.515 7 1.2 99.7

16 2 .3 100.0

Total 596 100.0

Table 5.3 presents the correlation matrix among PHACH,

MTACH, INACH, Rank, AVAB, MTRSN, OPTL and gender. Only AVAB

and MTRSN are significantly correlated with DPTL at the 5% level

(.26 and .36 respectively).

The analysis of variance of DPTL based on ethnic

background, school and gender found that all of these variables

significantly influence on DPTL. (ethnic background: F(7,588) =

4.23, p < .001; school: F(18,577) = 30.56, p < .001; gender:

F(1,594) = 6.40, p = .O1).

On average each item was answered correctly by 63.9

percent of the students (SD = 13.68). The lowest facility value

was 28 percent (item no.ll) and the highest was 89.9 percent

(item no.l). The following sections will present the distribution of

students' responses in each sub-unit.

58


8/27

2.2 The generation of sound (DPH1)

Only 10 percent of the students did not know that sound is

generated by vibration. They perceived that if the inside air of a

whistle is moving out or if there is wind inside the whistle sound

would be produced (7.1% and 3.0% respectively) (item no.l).

Item no.2 questioned what would happen when the gamelan

players touch the end of pieces of the gamelan instrument inorder to stop its sound. About 12.4 percent of the students stated

that the transmission of sound of the gamelan will be stopped.

Others (5.4%) predicted that the sound would be absorbed by the

players' bodies.

Only students who answered correctly both item no.l and

item no.2 were considered as having mastered the sources ofsound concept (DPH1).

Crosstabulation analysis results indicate no significant

differences on the students' responses among ethnic backgrounds

( 2 = 7.32, df = 7, p = .40) nor between genders (2

= 2.49, df

= 1, p = .12) but there were significant differences among schools

( 2 = 75.42 df = 18, p < .001).

2.3 The transmission of sound (DPH2)

Item no.3 is concerned with the explanation of why soundcan pass through a medium. About 20.1 percent of the students

59


9/27

stated that there must be air inside, and 12.4 percent stated that

the particles of the medium move and carry the sound.

By completely closing a room we can be protected from any

unexpected outside sound. Twenty-four percent of the studentsbelieved that this is because the movement of particles which

carry that sound is stopped. About 15.6 percent said that it is

because movement of air is stopped (item no.4).

Only students who were able to answer correctly both of

those questions were considered to have mastered the concept

transmission of sound (DPH2).Crosstabulation results indicate significant differences on

students' responses among schools (2

= 59.23, df = 18, p

west kalimantan students' conceptions about sound

Documents