Creative Education
2012. Vol.3, No.8, 1291-1296
Published Online December 2012 in SciRes (http://www.SciRP.org/journal/ce) http://dx.doi.org/10.4236/ce.2012.38188
Effects of Science Process Skills Mastery Learning Approach on
Students’ Acquisition of Selected Chemistry Practical Skills in
School
Roselyn Chebii*, Samwuel Wachanga, Joel Kiboss
Department of Curriculum Instruction and Educational Management, Egerton University, Njoro, Kenya
Received June 13th, 2012; revised July 20th, 2012; accepted August 2nd, 2012
The study investigated the effectiveness of Science Process Skills Mastery Learning Approach (SPROS-
MALEA) on students’ acquisition of Chemistry practical skills. The Solomon Four Group, Non-equiva-
lent Control Group Design was employed in the study. The study was carried out in Koibatek District,
Kenya where there has been persistent low achievement in the subject. 160 form two students from four
co-educational schools, purposively selected from the District were taught the same course content on
salts for a period of four weeks. The experimental group received their instructions through use of
SPROSMALEA approach and control groups using the conventional teaching method. The researcher
trained the teachers in the experimental groups on the technique of SPROSMALEA before the treatment.
Science Process Skills Performance Test (SPSPT) and Classroom Observaion Schedule (COS) were used
for data collection. The results of the study indicated that students in the experimental groups outper-
formed the control groups in the acquisition of selected Chemistry practical skills. It was concluded that
SPROSMALEA enhanced better performance in Chemistry than the conventional teaching method. Che-
mistry teachers should be encouraged to incorporate this method in teaching and should be included in
regular in-serving of teachers in Kenya.
Keywords: Science Process Mastery Learning Approach (SPROSMALEA); Acquisition of Selected
Chemistry Practical Skills; Conventional Teaching Method
Introduction
The word science is a noun derived from a latin term “scien-
tial” meaning knowledge (Ross, 2000). According to Ross, sci-
ence is a process or way of arriving at a solution to a problem
or understanding an event in nature that involves testing a pos-
sible solution. Effective science learning depends on the me-
thod and techniques employed by the teachers during instructio-
nal process (Das, 1985). Students learn science best when the
teaching methodology enables them to get involved actively in
class activities. They should participate actively in doing ex-
periments, carrying out demonstrations, class discussion and
other relevant learning experience. Ajaja (2007) identified the
objectives of teaching science to include 1) Knowledge of sci-
ence academic discipline 2) To acquire the skills of scientific
method 3) Having clear explanations for societal issues through
increasing interest in science literacy and societal goal 4) For
personal needs 5) For career awareness. If students actively en-
gage in Science processes they can come to recognize that sci-
entific knowledge is based on experiments in which meaning of
data is negotiated and theories are not absolute. Knowledge in
this context consists of learning experimental methods and the
norms and practices of scientific communities as much as it
does learning known facts and correct theories within a domain
(Wheeler, 2000).
Chemistry occupies a central position amongst the science
subjects. It’s a core subject for medical science, textile tech-
nology, agricultural sciences, chemical engineering. According
to Ohodo (2005), Chemistry contributes generating to the at-
tainment of the aims of education and specifically helps indi-
viduals to develop effective process skills, critical thinking and
competencies required for dealing with observation, classifica-
tion, inferences, experimentation and interpretation of data and
generalization.
SPROSMALEA is an Acronym got by integrating existing
science process skills and mastery learning methods. It was an
approach used in teaching the experimental groups in this study
to see whether it improved in the acquisition of Chemistry
practical skills.
The study aim at finding the effect of SPROSMALEA on
students’ acquisition of selected Chemistry practical skills. This
approach is an integration of existing Science Process Skills
and Mastery Learning in an effort to come up with a new ap-
proach (SPROSMALEA). This method of teaching had not
been tried out in Chemistry teaching and learning in Koibatek
District, Kenya where performance in the subject had continued
to decline.
Research Hypothesis
The purpose of the study was to determine the effects of Sci-
ence Process Skills Mastery Learning Approach (SPROSMA-
LEA) on Students’ acquisition of selected Chemistry practical
skills.
The following null hypothesis was tested in this study at sig-
nificance alpha level of .05.
*Corresponding author.

R. CHEBII ET AL.
Ho1: There is no statistically significant difference in acqui-
sition of selected Chemistry practical skills, experimenting, ob-
servation and inferences between students who are exposed to
SPROSMALEA and those who are not.
Research Design
The study used Solomon Four Non-equivalent Control Group
Design. This is because there was non-random selection of stu-
dents to the groups. Secondary school classes exists as intact
groups and school authorities do not normally allow the classes
to be dismantled and constituted for research purposes (Fraen-
kel & Wallen, 2000).
Four groups of participants, the Experimental Group One
(E1), Experimental Group Two (E2), Control Group One (C1)
and Control Group Two (C2) was used. Groups E1 and E2
formed the experimental groups which received treatments
(SPROSMALEA) while C1 and C2 were the control groups that
did not receive the treatment. Groups E1 and C1 received
pre-test while E2 and C2 did not. All groups received the post
test at the end of the course. To avoid interaction of students
from different groups that may contaminate the results of the
study, one class from a school constituted one group of subjects,
hence four schools were required for this study. The selected
classes were randomly assigned to the experimental and control
groups (Mugenda & Mugenda, 2003; Borg & Gall, 1989; Mutai,
2000).
Sample
The actual sample size that participated was 160 form two
students, selected using purposive sampling method from 4-co-
educational schools which met the requirements (having labo-
ratories apparatus, qualified science teachers and could easily
be accessed using the Nakuru-Eldama Ravine road), situated in
Koibatek District, Kenya (Table 1).
Development and Use of Teaching Materials
The content to be used in the class instruction was developed
and based on the revised KIE 2002 chemistry syllabus, teachers
guide, students textbook and other relevant materials. Teachers’
manuals included the content to be covered and lesson plans to
be used in teaching topic salts in form two chemistry. Student
manuals were the worksheets including the guidelines and pro-
cedures the learners would use when performing experiments in
the laboratory. These manuals were only used in the experi-
mental groups. The teacher had to mention the expected objec-
tives the learner had to achieve at the end of the lesson, intro-
duced the lesson, discussed the results of the experiment, give
assignments and remedial to those learners who had not mas-
tered the concepts and skills. In control groups, the conven-
Table 1.
Sample size of the study.
Groups Number of students
E1 38
E2 39
C1 46
C2 37
Total 160
tional methods of teaching was used. The teachers in the ex-
perimental groups were trained in the new approach, given
teaching modules and student manuals by the researcher. Classes
in all the four groups used the same curriculum materials and
spent about the same time four weeks on topic salts as recom-
mended in the syllabus.
Instrumentation
Two instruments were used to collect the data:
1) Science process skills performance test SPSPT.
2) Classroom observation schedule.
Science Process Skills Programme Test (SPSPT)
Science Process Skill Performance Test (SPSPT) was used to
evaluate the performance of process skills (experimenting, ob-
servation and inferences) by the student. It contained two prac-
tical items on salts. This instrument was pilot tested in two
secondary schools with a similar characteristic in Koibatek
District, but did not take part in the study. The reliability was
estimated using K-R 21 and a reliability of .88. The reliability
coefficient level is above .7, hence acceptable. This implied that
there was a good internal constituency of items (Frankel &
Wallen, 2000).
Classroom Observation Schedule
COS was used to observe four lessons on the topic salt to
provide data on teacher and students activities during instruc-
tion processes. It had two sections which provided data on the
teachers and students activities respectively. It contained eleven
teachers and students related items. The instruments pilot tested
in two schools in Koibatek District, not included in the study.
Sixteen items were used in the calculation of Cronbach’s Alpha
(α) for the test of how reliable the student activity was and
Cronbach’s alpha .97 was obtained. In the teacher’s activities
eleven observations were used in the calculation of the Cron-
bach’s alpha (α). Cronbach’s alpha coefficient of .93 was ob-
tained. Both items had a high reliability coefficient hence ac-
ceptable since alpha was above .7 (Frankel & Wallen, 2000).
Data Collection Procedure
The students in the study were randomly assigned into the
four groups experimental group I (E1), experimental group II,
control group I (C1) and control group II (C2). A pre-test was
conducted in one experimental group (E1) and one control
group (C1) in order to measure the students entry behaviour
before the treatment. In experimental groups E1 and E2 SPROS-
MALEA was used while in control groups C1 and C2 conven-
tional teaching method was used. At the end of the treatment
period the post test (SPSPT) was administered to all groups.
The researcher supervised the teaching and scored the pre-test
and post-test. COS was used to provide data in the teachers and
students activities. Data was collected from at least four lessons
taken from each of the experimental and control groups .The
frequency of the claas activities observed in the study was cal-
culated as means roups.
Results and Discussion
SPSPT was used to pre-test for the two groups, experimental
1292

R. CHEBII ET AL.
group (E1) and control group (C1). This was done to enable the
researcher to check their entry behavior and to determine whether
the groups were similar before the commencement of the Che-
mistry topic on salts.
The results in Table 2 revealed that the difference in students
scores in the SPSPT were not statistically significant t(82) =
1.48, P > .05. This indicates that the groups used in the study
exhibited comparable characteristics and therefore suitable for
the study.
Effects of SPROSMALEA on S tu dents Acquisition of
Selected Chemistry Practical Skills (SPSPT)
The hypothesis of the study sought to find out whether there
was any statistically significant difference in scores in the ac-
quisition of science process skills (experimenting, observation
and inferences) between students who were exposed to SPROS-
MALEA and those who were not. Table 3 shows (SPSPT)
post-test mean score obtained.
Results in Table 3 shows that the mean scores obtained by
students in E1, group (M = 36.41) and C1 group (M = 39.11)
before the commencement of treatment. The difference in mean
scores were not statistically significant (Table 2). But after the
treatment the student who were exposed to SPROSMALEA (E1
and E2) outscored the control groups. E1 group scored higher
mean (M = 58.15) than C1 group (M = 53.24). Also the mean
gain for E1(21.74) was higher than that of the whole groups
(18.08) and for the C1(14.13). This shows that the use of SP-
ROSMALEA enhanced the performance than the use of con-
ventional method.
Table 4 indicates that a statistically significance difference
exists between mean scores of the groups F(3,155) = 6.38, P
< .05. The null hypothesis could be rejected but the findings
could not indicate where the difference was. It was necessary to
carryout, Least Significant Difference (LSD) post hoc com-
parisons, to know which groups were statistically significant
different.
Table 2.
Independent sample t-test of the pre-test scores on SPSPT.
TEST GROUP MEAN SD t-value P-value
SPSPT E1
C1
36.41
39.11
13.22
12.89 .95 .34 .34
Note: Mean difference not significant at .05.
Table 3.
Comparison of means, standard deviations (S.D) and mean gain ob-
tained by the student on the SPSPT.
Variable Overall
N = 16
E1
N = 38
C1
N = 46
E2
N = 39
C2
N = 37
Pre-test mean 37.76 36.41 39.11
S.D 13.06 13.22 12.89
Post-test Mean 55.84 58.15 53.24 60.58 51.81
S.D 9.99 12.89 10.22 7.54 9.31
Main gain 18.08 21.74 14.13
Table 4.
ANOVA of the post-test scores on the SPSPT.
Test Group SS DF Mean square FP-Value
SPSPT Between groups
within groups
1969.39
15956.36
3
155
656.46
102.94 6.38.000
Total 17925.75 158
Note: Mean difference is significant at .05 level.
Table 5 shows the results of post hoc comparisons test of
significance for a difference between two means.
The SPSPT means of groups E1 and C1, groups E1 and C2,
groups E2 and C1, groups E2 and C2 were statistically significant
different at .05 α level.
However there was no statistically significant difference in
the means between groups E1 and E2 groups C1 and C2. From
this, the students in the experimental conditions outperformed
students in the control groups. It can therefore be concluded
that SPROSMALEA approach used by experimental groups led
to a relatively higher acquisition of practical skills (experiment,
observation and inferences in the learning of salts, than those
who used the conventional method.
Since the study involved non-equivalent control group design,
there was need to confirm there results by performing analysis
of covariance (ANCOVA) using students Kenya Certificate of
Primary Education (KCPE) scores as covariate.
Analysis of covariance reduces the effects of initial group
differences statistically by making compensating adjustments to
the post-test means of the groups involved (Borg & Gall, 1989;
Wachanga, 2002).
Table 7 shows ANCOVA results based on the adjusted
means of the four groups displayed in Table 6. There is statis-
tically significant difference in the SPSPT mean score of the
four groups. F(3,154) = 6.12, P < .05. P value is less than .05.
The post hoc pairwise comparison based on ANCOVA Ta-
ble 8, shows that there is a statistically significant difference in
the following groups.
Table 5.
Post hoc comparisons of SPSPT post-test means for four groups.
I GroupJ Group Mean differences (I-J)P-value
E1
E2
C1
C2
–2.42
4.92*
6.35*
.30 (NS)
.03
.01
E2
E1
C1
C2
2.42
7.34*
8.77*
.30 (NS)
.00
.00
C1
E1
E2
C2
–4.92*
–7.34*
1.43
.03
.00
.53 (NS)
C2
E1
E2
C1
–6.35*
–8.77*
–1.43
.01
.00
.53 (NS)
Note: *Significant at P < .05. (NS) = Not Significant.
Table 6.
Adjusted SPSPT post-test mean scores for ANCOVA with KCPE
scores as covariate.
Group N Mean Score
E1
E2
C1
C2
38
39
46
37
58.16
60.58
53.18
51.94
Table 7.
Analysis of covariance (ANCOVA) of the post-test score of SPSPT
with KCPE.
Sum of squareDFMean squares F P-value
KCPE
Group
Error
3317.62
1900.31
15933.35
1
3
154
3317.62
633.44
103.46
32.07
6.12
.00
.00
Note: F = 6.122; DF = 3; P < .05. Mean difference is significant at .05 level.

R. CHEBII ET AL.
Table 8.
Post hoc pairwise comparisons: Post-test score of SPSPT.
I Group J Group Mean differences (I-J) P-value
E1
E2
C1
C2
–2.36
4.98*
6.22*
.32 (NS)
.03
.01
E2
E1
C1
C2
2.36
7.33*
8.57*
.32 (NS)
.00
.00
C1
E1
E2
C2
–4.98*
–7.33*
1.24
.03
.00
.59 (NS)
C2
E1
E2
C1
–6.22*
–8.57*
–1.24
.01
.00
.59 (NS)
Note: *Significant at P < .05. (NS) = Not Significant.
1) Groups E1 and C1
2) Groups E2 and C1
3) Groups E2 and C2
4) Groups E1 and C2
The differences in means of the groups E1 and E2 and groups
C1 and C2 were not statistically significant. It is evident the
SPROSMALEA had similar effects to both experimental groups.
But the control groups C1 and C2 denied of this treatment had a
lower mean score and hence were outperformed by the experi-
mental groups. The results of ANOVA and ANCOVA confirm
that there was a statistically significant difference in the mean
scores of the experimental and control groups. Therefore HO2
was rejected.
Analysis of Teachers and S t ud ents A ctivities during
Chemistry Lessons
Results of Classroom Observation Schedule
Data were collected from four lessons taken from each of the
experimental and control groups. The frequencies of the class-
room activities observed in the study were calculated as means
and the results reported in Table 9.
Table 9 shows the classroom activities observed during in-
structions. It attempts to identify possible similarities or differ-
ences among teacher/students activities when SPROSMALEA
and conventional method were used in Chemistry lessons.
A perusal of the results indicates that the teacher activities in
the experimental groups (E1 and E2) outperformed those in the
control groups (C1 and C2). The total mean scores of teacher
activities in the experimental group were 63.25 and 73.05 while
in the control group were 51.25 and 36.5. In experimental,
teachers manual guided the teacher on what to do. The teacher
had to make sure that the objectives were achieved before
moving to the next instruction. Learners were required to mas-
ter the Science Process Skills (experimenting observation and
inferences).
Student activities in the experimental groups had a higher
mean frequencies than the control groups. This is evident by the
total mean score of 85.5 and 83.25 in the experimental groups
and 45.26 and 59.25 in the control groups. Use of student man-
ual (Appendix E), must have made learners in the experimental
group to be orderly and active, compared to those in the control
groups.
Comparing the teacher/student activities, we can see that the
students did more activities than the teachers. This is evident by
the means of students of 85.5, 83.25, 45.25 and 59.25, teacher
Table 9.
Comparisons of teachers and students activities during chemistry les-
sons on salts.
Teachers activity Means of frequencies
groups
E
1 E 2C1C2
1.Reinforce appropriate response 6.90 9.504.503.75
2.Ask questions 3.00 4.754.751.50
3.Demonstrate a skill 3.25 4.503.002.00
4.Re-read problems 6.50 8.755.505.75
5.Re-state problems 5.50 8.255.252.25
6.Supervises activities 8.00 6.254.755.25
7.Give precautions 6.25 7.505.254.00
8.Encourage students to give observations 8.50 8.005.502.00
9.Encourage students to write orderly results 6.75 5.003.752.50
10.Review results 3.75 5.305.504.00
11.Encourage to give inferences 5.75 5.253.503.50
Total 63.25 73.0551.2536.50
Student activity Means of fre quencies
groups
E
1 E 2C1C2
1.Respond to teachers question 5.50 5.252.753.25
2.Follow instructions 5.75 5.701.254.00
3.Perform experiment 8.25 7.503.254.75
4.Makes observations 5.00 5.754.504.50
5.Recalls properties 6.50 2.753.252.00
6.Identify changes occurring in a reaction 6.75 6.003.255.50
7.Identify observable characteristics 5.75 5.002.503.50
8.Infer relationship 5.00 7.502.003.75
9.Infer an effect 5.00 3.751.753.50
10.Ask questions 3.75 3.251.502.50
11.Consult other students 6.75 5.754.253.25
12.Express agreement or disagreement with action 3.75 6.503.505.00
13.Repeat experiments to clarify the results 2.25 2.001.752.50
14.Take precautions 5.75 8.752.502.75
15.Contribute during class discussion 4.75 5.004.505.00
16.Give conclusions 2.75 3.752.751.25
Total 85.5 83.2545.2559.25
activities of 63.25, 73.05, 51.25 and 36.5. This was a learner
centre approach, since learners were more involved than the
teachers.
Quantitative analysis was supplemented by qualitative de-
scription to provide fuller picture of the findings particularly in
those areas that are not easily amendable to quatification. The
teachers in the experimental groups had to state the objectives
to be achieved at the start of the lesson, introduce the topic and
also monitor the learners activities during instruction. KIE
(2006), recommends that learners centre approach is most ap-
propriate, however learners require teachers guidance. Gavora
& Hannafin (1995), from his research said that learning does
not occur by only observation but by doing. This implies that
interaction should be able to maintain attention and fasten the
creation and storage of knowledge and skills.
From the results the students who used SPROSMALEA
achieved significantly higher mean scores in the SPSPT than
those who did not use. The use of SPROSMALEA offered a
departure from the traditional methods of teaching in a class-
room and made the learners to be practical oriented. Practical
1294

R. CHEBII ET AL.
tests measures the development of the practical skills of the
learner in the teaching of chemistry. In this study, the experi-
mental groups out performed the control groups. Experimental
groups were able to master the selected process skills (experi-
menting, observation and inferences) better than the control
groups. Allsops & Woolnough (1985): Hudson (1990) in their
research showed that practical work in science aids in acquisi-
tion of science process skills and scientific knowledge. This
approach encouraged practical work, since most of the lessons
in this topic salts were mainly class experiments or teacher
demonstration. Galyam & Lecrange (2003) did a study in teach-
ing learners some thinking skills and how to improve their use
in science. There was improved use of thinking skills, increase
of critical discussions and use of meta cognitive abilities as well
as acquisition of content knowledge.
Cunningham & Dirk (2006), did a research aimed to teach
science process skills that they believed were needed for suc-
cess in the introductory biology courses. The skills were taught
using scanffolding approach that progressively, challenge stu-
dents to master the skills, while weaving them together through
individual homework and small groups work in class. Those
who participated learned a topic in depth, think like a scientist
and also gain valuable skills. In this study the use of remedial,
assignments and feedback helped the learners to master the
skills. Feedback helps students identify what they have learned
well and what they have not learned well. Areas that were not
learned well are allocated more time to achieve mastery. Bizar
& Hyde (1989), argued that in many cases learners have to be
debriefed identify some of the finer points of what has been
observed. The activities are designed however for student in-
vestigation not teacher explanation. So debriefing should occur
only after experimenting and attempts to make inferences will
have been exhausted. Not only must students be actively en-
gaged to learn chemistry but, the teachers must give adequate
guidance, support and encouragement while at work when sci-
entific problem is proceeding. The teacher acts as a facilitator
creating learning conditions in which students actively engage
in experiments, interpret, explain data and negotiate under-
standing of findings with co-experimenters and peers (National
Research Council, 2005).
Teachers in the experimental groups facilitated the practical
work done by the students. They moved from one working
group to the other, to check whether students were following
instructions, making correct observations and recording correct
inferences. This enhanced the acquisition of science process
skills. Rillero (1998) from his research argued that exhaustive
knowledge of science content is impossible, mastery of science
process skills enables students to understand a much deeper
level, the content they do know and equips them for acquiring
content knowledge in the future. Use of SPROSMALEA en-
hanced the acquisition of science process skills.
CONCLUSION
Conclusion
In this article an attempt was made to use the results of the
study to test whether the hypothesis was false or true. From the
post-test and pre-test results, the mean score, obtained by stu-
dents in groups E1 and groups C1 were not statistically signifi-
cant. But after treatment, the students who were exposed to
SPROSMALEA (E1) outscored the control group (C1). Also the
mean gain by groups E1 and (E2) was higher than that of the
control groups (C1 and C2).
From the ANOVA results of the post-test, there was statistic-
cally significant difference in the means between groups (E1
and E2) and adjusted means of the four groups showed that
there was statistically significant difference in the means of the
four groups. From these results the hypothesis was rejected.
Classroom observation schedule was used to monitor teach-
ers and students activities. From the results the students did
more activities than the teachers. This is evident by Table 9.
Experimental groups were able to master the selected process
skills (experimenting, observation and inferences) than the con-
trol groups (Allsops & Woolnough, 1995). Hudson (1990) in
their research showed that practical work in science aids in
acquisition of science process skills and scientific knowledge.
The finding is consistent with several literature sources.
Based on this study, it can be concluded that SPROSMA-
LEA approach enhanced the acquisition of science process
skills than the use of conventional teaching methods. This is
evident by the significantly high mean scores in the SPSPT
attained by experimental groups than those in the control groups.
Chemistry teachers should incorporate this approach in teach-
ing Chemistry at secondary school level especially in the topic
salt, where more of the work is experimenting, making obser-
vations and inferences. Teachers’ need to make use of more in-
teractive approaches actively involves learners in the teaching-
learning process.
REFERENCES
Ajaja, O. P. (2007). Teaching methods across disciplines. Agbor: All-
well Publishers.
Allsops, T., & Woolnough, B. (1985). Practical work in science. Cam-
bridge: Cambridge University Press.
Bizar, M., & Hyde, A. A. (1989). Thinking in context: Teaching cogni-
tive processes across the elementary school curriculum. White Plains,
NY: Longman.
Borg, W. R., & Gall, M. D. (1989). Educational research. An introduc-
tion (5th ed.). White Plains, NY: Longman.
Das, R. S. (1985). Science teaching in school. New Delhi: Sterling
Publishers.
Dirks, C., & Cunningham, M. (2006). Enhancing diversity in science:
Is teaching science Process skills the answer? Life Science Education,
5, 218-226.
Fraenkel, R. J., & Wallen, E. N. (2000). How to design and evaluate
research in education (4th ed.). San Francisco: McGraw-Hill.
Galyam & Lecrange (2003). Teaching thinking skills in science to
learners with special needs. International Journal of Special Educa-
tion, 18, 84-94.
Gavora, M. J., & Hannafin, M. J. (1995). Perspectives on the design on
human-computer interactions. Issues and implications. Instructional
Science, 22, 445-447.
Hodson, D. (1990). A critical look at practical work in school science.
School Science Revi ew, 71, 33-40.
Kenya Institute of Education (2002). Teacher’s preparation guide. The
New Secondary Education C u r r iculum. Nairobi: Self.
Kenya Institute of Education (2006). Secondary chemistry teachers
handbook. Nairobi: Self.
Mugenda, O., & Mugenda, A. (2003). Research methods quantitative
and qualitative approa c h e s. Nairobi: Act Press.
Mutai, K. B. (2000). How to write quality research proposals. New Delhi:
Thellery Publications.
National Research Council (2005). How students learn science in the
classroom. Washington DC: The National Academy Press.
Ohodo, G. C. (2005). Principles and practice of chemistry education in
Nigeria. Enugu: Enugu State University of Science and Technology.

R. CHEBII ET AL.
1296
Rillero, P. (1998). Process skills and content knowledge. Science Ac-
tivities, 35, 3.
Ross, B. (2000). Modern trends in education. London: The Macmillan
Press Ltd.
Wachanga, S. W. (2002). Effects of cooperative class experiment teach-
ing method on secondary school student’s motivation and achieve-
ment in chemistry. Ph.D. Thesis, Njoro: Egerton University Njoro.
Wheeler, G. F. (2000). Three faces of inquiry. In J. M. Instress, & E. H.
Van Zee (Eds.), Inquiring into inquiry learning and teaching in sci-
ence (pp. 14-19). Washington DC: American Association for the Ad-
vancement of Science.