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Asia-Pacific Forum
on Science Learning and Teaching, Volume 13, Issue 1, Article 4 (Jun., 2012) |
To answer the first research question students’ alternative conceptions of concepts related to simple harmonic motion are described in the part one of the results. In part one the most unedited occurring alternative conceptions of the students’ responses on the concepts related to SHM is highlighted. The emphasis here is not on the number of the students who made the responses but on the most occurring response of the students regarded as alternative conception with reference to scientifically accepted conception. In part two the data for answering the second research question and testing the hypothesis are presented.
Q1. What is Simple Harmonic Motion?
Students’ Responses (SR)
Experimental group.
- Simple harmonic motion is the motion that takes place between two points in a fixed position which is directly proportional to the oscillating body
- It is to and fro movement of a body where by the rate of change of acceleration is proportional to the displacement of the body and the move in the direction of the force.
Control group.
- Simple harmonic motion is the movement of a body to and from about a fixed point
- SHM is the time of motion in which the object or person moves to and fro or it is to and fro motion
- SHM is a motion in which a body moves to and fro from a constricted point so that at any point of its movement, it maintains a constant velocity.
Q2. What is Amplitude of Simple Harmonic Motion?
SR: Experimental group.
- Amplitude is the maximum forward or back word movement of a body in simple harmonic motion
- Amplitude is the maximum velocity of displacement per one second.
- It is the amount of the speed of its frequency
Control group
- Amplitude of SHM is the displacement of a body per second
- The amplitude of a SHM is the displacement of a body from its equilibrium position.
Q3. Explain the term period of Oscillation.
SR: Experimental group.
- Period of oscillation is the number of civil or revolution mode in me second
- Period of oscillation it is the time taken to go and from per second
Control group.
- Period of oscillation is the movement of the vibrating oscillatory body in a second
- Period is the time interval
- Period at oscillation is the time equals to the length at pendulum and acceleration due to gravity
Q4. What is frequency of a Simple Harmonic Motion?
SR: Experimental group.
- Frequency is the speed that is used during the function of SHM
- Frequency of a simple pendulum is the no of the to and from movement of the pendulum built or it is the member of oscillation of the pendulum hulb.
Control group.
- Frequency is the number of times or period it takes a body to compete in one second
- Frequency is defined the number of per second of vibration body.
- The frequency of a simple pendulum is the period in which the pendulum moves front and back.
Q5. What happens to frequency and period when the speed of an object in SHM increases.
SR: Experimental group.
- The frequency is increased and the period is increased
- When the speed of an object performing SHM increases the frequency will.
- When the speed of an object performing simple harmonic is decreased to its frequency and period, the frequency of that object is reduced.
Control group.
- When the speed of an object performing simple harmonic motion is increased its frequency and period also
- When the speed of an object performing simple harmonic is increased the frequency will decrease while the period will increase.
Q6 On what does period of Simple Pendulum Depend?
SR: Experimental group
- The period of a simple pendulum depends on the direct of wind and the angle it is been set through (the must be set through a small angel)
- Period depends on how and when you leave it to scoring
Control group.
- The period of a simple pendulum is dependent on the constant to and fro movement along the fixed point
- The period depends on the frequency
- The period of a simple pendulum depends on the number of oscillations and frequency
Q7. Describe the changes in K.E of a swinging pendulum body with respect to its position.
SR: Experimental group.
- When the pendulum is at nt it is possessing an energy called potential energy but when a little external force is applied, the potential energy changes to kinetic energy (K.E), ie. The external force that is during acted upon the pendulum gave right kinetic energy.
- Kinetic energy is the energy of a body in motion and when a pendulum hob swings to and fro it make one oscillation and the position of the pendulum bulb changes
- The changes in the K.E of a swing pendulum bob with respect to its position is that as long as the bob keeps moving it reduces the speed until it finally gets to a stop after a long period of time
Control group.
- When a simple pendulum bob is in position it is said to possess a potential energy them moment of starts swinging there is a change in motion potential energy to kinetic energy which means the pendulum bob is in motion
- The swing of pendulum bob is the changes of the K.E the pendulum is displaced through a large angle.
Q8. Explain the balancing of velocity and acceleration at the equilibrium position of an object performing SHM.
SR: Experimental group.
- The velocity is = 0 is fixed
- The velocity → O, the acceleration → max
- The velocity and acceleration equal to zero
Control group.
- The acceleration and velocity are equal and opposite
- Its velocity and acceleration decreased as the motion continued.
- Velocity and acceleration → constant in position
- There is displacement in its velocity and acceleration
Q9. What are the effects of wind on a swinging pendulum bob?
SR: Experimental group.
- It effect the period
- It given wrong oscillation for second
- It frequency varies
Control group.
- It will increase the wind
- It causes the displacement
- That a gravitational force acts upon it but not two strong in stopping the oscillation
Q10. What are the effects of a large displacement on a swinging pendulum bob?
SR: Experiment group.
- It moves faster and not oscillates but only move on a straight line.
- The swinging bob will move to a different direction and when it return it dash with the retort stand
Control group.
- It will be curve when it suppose to be arc
- It does not accelerate properly i.e. it does not come back to its fixed point
- It will not make the pendulum bob not to complete oscillation.
The results obtained from the study when the students’ responses were grouped into the levels of understanding (Sound understanding, Partial understanding and Alternative conception) are presented in tables 1, 2 & 3.
Table1. Number and percentage of students of the control group in each level of understanding of concepts in SHM before and after the treatment
N=61
Pretest(Before treatment)
Posttest(After treatment)
S/N
SU*
PU**
AC***
SU
PU
AC
Freq.
%
Freq.
%
Freq.
%
Freq.
%
Freq.
%
Freq.
%
1
13
21.0
14
23.0
34
56.0
29
48.0
21
34.0
11
18.0
2
14
23.0
6
10.0
41
67.0
35
57.0
11
18.0
15
25.0
3
13
21.0
17
28.0
31
51.0
32
52.0
13
21.0
16
26.0
4
25
41.0
1
2.0
35
57.0
38
62.0
2
3.0
21
34.0
5
13
21.0
11
18.0
37
61.0
24
39.0
11
18.0
26
43.0
6
5
8.0
9
15.0
47
77.0
10
16.0
14
23.0
37
61.0
7
0
0.0
0
0.0
61
100.00
4
7.0
4
7.0
53
86.0
8
6
10.0
6
10.0
49
80.0
12
20.0
6
10.0
43
70.0
9
5
8.0
1
2.0
55
90.0
8
13.0
5
8.0
48
79.0
10
1
2.0
1
2.0
59
96.0
5
8.0
5
8.0s
51
84.0
*Sound understanding.**Partial understanding ***Alternative conception
Information in table 1 shows that students in control group fairly shifted their level of understanding from alternative conception to sound and partial understanding of the concepts. For instance, 26 students shifted from alternative conception of the meaning of SHM (item 1) to sound understanding while 7 of the students moved from the same idea to partial understanding. There was not much shifting in item 7 as shown in table 1.
Table 2. Number and percentage of students of the experimental group in each level of understanding of concepts in SHM before and after the treatment with 4-Es
N=63
Pretest(Before treatment)
Posttest(After treatment)
S/N
SU*
PU**
AC***
SU
PU
AC
Freq.
%
Freq.
%
Freq.
%
Freq.
%
Freq.
%
Freq.
%
1
19
30.0
9
14.0
35
53.0
47
74.0
10
16.0
6
10.0
2
10
16.0
12
19.0
41
65.0
40
63.0
12
19.0
1
17.0
3
6
10.0
25
40.0
32
50.0
30
48.0
27
43.0
6
10.0
4
7
11.0
4
6.0
52
83.0
46
73.0
1
2.0
1
25.0
5
6
10.0
20
32.0
37
58.0
38
60.0
14
22.0
1
17.0
6
8
13.0
7
11.0
48
76.0
19
30.0
21
33.0
23
37.0
7
2
3.0
01
2.0
60
95.0
24
38.0
5
8.0
34
54.0
8
2
3.0
3
5.0
58
92.0
33
52.0
10
16.0
20
32.0
9
2
3.0
3
5.0
58
92.0
20
32.0
27
43.0
16
25.0
10
0
0.0
1
2.0
62
98.0
19
30.0
15
24.0
29
46.0
*Sound understanding.**Partial understanding ***Alternative conception
Table 2 shows that 90% of the students either maintained their level of understanding or shifted their level of understanding from alternative conception to partial or sound understanding after treatment. It was also observed that before the treatment 53% of the students had alternative/no conception of concept of SHM (item 1) and after the treatment only 10% of the students remained at the alternative conception level.
Table 3. χ2 Statistics on the level of understanding of concepts related to simple harmonic motion by treatment
S/No
Group
2
SU*
1
PU**
0
AC***
df
χ2
1
Experimental
Control
47
29
10
21
6
11
2
9.24
5.991**
2
Experimental
Control
40
35
12
11
11
15
2
3.91
5.991
3
Experimental
Control
30
32
27
13
6
16
2
9.49
5.991**
4
Experimental
Control
46
38
1
2
16
21
2
1.74
5.991**
5
Experimental
Control
38
24
14
11
11
26
2
9.58
5.991**
6
Experimental
Control
19
10
21
14
23
37
2
7.44
5.991**
7
Experimental
Control
24
4
5
4
34
53
2
18.50
5.991**
8
Experimental
Control
33
12
10
6
20
43
2
19.17
5.991**
9
Experimental
Control
20
8
27
5
16
48
2
36.25
5.991**
10
Experimental
Control
19
5
15
5
29
51
2
38.82
5.991**
**P≤.05
*Sound understanding.**Partial understanding ***Alternative conception
Table 3 above indicates that there is significant difference in the level of understanding of concepts related to SHM in items 1, 3, 4, 5, 6, 7, 8, 9&10 between the students of the experimental group and control group. There is no significant difference in items 2 and 4 between the experimental and control groups. The calculation of the χ2 statistical value was done using manual calculator since the numbers were very few.
