2. Method
One-group pretest-posttest design was used in this study. It was determined to measure the effect of sample
lesson plan on student’s achievement level. The study was conducted in the fall semester of the 2013-2014 academic
year. The participants were 12 eight-grade students (four boys and 8 girls). In teaching the subject to the students,
the sample lesson plan based on STEM approach was used in compliance with 5E learning cycle model.
2.1. Development of Instructional Design
A sample lesson plan were developed for the topic of acids and bases which will be an example for our
science teaching programme based on STEM education. Specific activities in each discipline can be seen below:
1. Engagement Phase: In this phase, the aim is to determine the students’ prior knowledge and motivate them
to engage in learning the topic.
Science Discipline: Learners are clustered into groups of three. A case study questions are presented to the
students in order to make them discuss with each other on acids and bases. Then, students are asked to share their
thoughts about the case and various examples of acids and bases from their daily lives.
2. Exploration Phase: In this phase, each group is expected to record their observations and ideas. Then, they
share their ideas with others and the teacher. The activities require the use of science process skills such as
observing, measuring, classifying, inferring, predicting, communicating, defining operationally and collecting data
during hands-on activities.
Science Discipline: The following five experiments on acids and bases are applied on students:
x The teacher gives some solutions used in daily life and a red litmus paper to each group. The students try to
distinguish these solutions as acids or bases by using blue litmus paper. Then, students show that acids change
blue litmus paper to red and red litmus paper remains the same. Bases change red litmus paper to blue and blue
litmus paper remains the same as well.
x Students design an experiment on the electricity of acid and base solutions.
x Students measure the pH level of various matters by using pH scale and discuss the effects of pH level on
matters and living organisms.
x Students design an experiment to show that acid and base cause neutralization reactions when they are
combined.
x Students show the effects of acids and bases on various matters.
3. Explanation Phase: In this phase, the teacher explains the concept in accordance with students’ answers
that they acquired as consequences of their previous experiences. They identify acids and bases by using the
physical properties, the relation between acids and bases clarifies that the strength of acid solutions increases with
the amount of H+ ions while the strength of base solutions increases with the amount of OH- ions in the solutions.
The teacher gives examples for acidic and basic substances in daily life, explains that solutions with a pH value
lower than 7 is acid and a solution with a pH value higher than 7 is base, clarifies that a solution with a pH value
equal to 7 is neither an acid nor a base but a neutral solution. Then, the teacher states that strength of an acid
increases with a decrease in pH and strength of a base increases with an increase in pH, explains that NO2 and SO2
gases cause acid rains. Additionally, he/she presents scientifically correct explanation by using instructions based on
computers and examples from daily life in order to make concepts more clear.