The effect of guided discovery on students' Physics achievement

The study investigated and contrasted the relative effectiveness of guided discovery, demonstration and traditional lecture method of teaching on students’ achievement in rotational motion. Grade 11 students from three selected preparatory schools in Ilu Aba Bora Zone located in southwestern part of Ethiopia took part in the study. The specific research design adopted in the study was pretest-posttest nonrandomized control groups experimental design. A purposive sampling technique was used to select three preparatory schools out of six preparatory schools in the zone. The whole research process took place within the natural classroom setting. The guided discovery, demonstration and the traditional methods were implemented in Mettu, Yayo Aida Thea and Gore Secondary and Preparatory Schools, respectively. The total number of students who took part in the study were 114 comprising of 73 males and 41 females. Researcher developed physics achievement test (RDPAT) with internal consistency of 0.77 using Kuder-Richardson formula 20 for pretest and 0.80 for posttest was used as data collection instrument in the study. The first semester result of the students who took part in the study was also used from the students’ rosters to establish the construct validity of the RDPAT test. The statistical tests used in the study were mean and standard deviation, ANCOVA, t-test, ANOVA, Scheffe post hoc test, Cohen’s d and η 2 effect sizes. Kolmogorov-Smirnov test was used to test the normality of the posttest scores, which is a key assumption in t-test and ANOVA. Analysis with ANCOVA and Scheffe test showed that the guided discovery method was the most effective teaching method (with an average gain score of 0.43) followed by the demonstration (average gain score 0.34). The traditional method was found to be the least effective (average gain score 0.26).The statistical analysis used students' background as the covariate. The R square value indicates that approximately 57% of the total variance in the achievement of the students in dynamics of rotational motion can be attributed to the specific teaching methods employed. There was no significant difference between the achievement of male and female students who were taught with guided discovery, demonstration and the traditional method. There was a significant difference between the achievements of each pair of high-, medium-, and low-achiever students’ scores who were taught with guided discovery and demonstration. This implies that the students’ achievement has a strong relationship with their background performance levels (high-, medium- and low-achiever) besides the effect of the instructional methods. It is recommended that physics teachers in the zone should implement guided discovery with sufficient guidance to help students create, integrate, and generalize knowledge through constructivist problem solving by providing them with materials available in physics lab or locally prepared teaching materials.