Ivan Samuel Sakerebau. 2026. The Effect of Using Flashcards on Students’
Vocabulary Mastery at the Nineth Grade of SMPN 3 Palopo. Thesis. English
Language Education Study Program, Faculty of Teacher Training and Education,
Cokroaminoto Palopo University. (Supervised by Paldy and Sri Rahayu)
This research aimed to determine whether the use of flashcards has a significant
effect on students’ vocabulary mastery at the ninth grade of SMPN 3 Palopo. The
research employed a quantitative approach using a pre-experimental method with a
one-group pre-test and post-test design. The population of this research consisted
of all ninth-grade students of SMPN 3 Palopo in the academic year 2025/2026. The
sample was 20 students selected through cluster random sampling. The instrument
used in this research was a vocabulary test consisting of 30 items focusing on nouns,
verbs, and adjectives. The research was conducted through three stages: pre-test,
treatment, and post-test. During the treatment, flashcards were used as instructional
media to teach vocabulary. The collected data were analyzed using descriptive
statistics and inferential statistics through Paired Sample T-Test in SPSS version
24. The findings showed that the mean score of the students increased from 81.85
in the pre-test to 91.95 in the post-test. The result of the Paired Sample T-Test
revealed that the significance value (2-tailed) was 0.000, which was lower than the
significance level of 0.05 (0.000 < 0.05). Therefore, the alternative hypothesis (H₁)
was accepted and the null hypothesis (H₀) was rejected. The findings indicate that
the use of flashcards has a significant positive effect on students’ vocabulary
mastery. Flashcards helped students improve their ability to recognize, understand,
remember, and use English vocabulary more effectively. Therefore, flashcards can
be considered an effective instructional medium for teaching vocabulary to junior
high school students.