Findings from the TIMSS 2019 Problem Solving and Inquiry Tasks

Ina V.S. Mullis, Michael O. Martin, Bethany Fishbein, Pierre Foy, and Sebastian Moncaleano

Chapter 4: Science Grade 8

Pepper Plants

Screen 10 – Evaluate an Example Experimental Setup

Screens 10 through 13 assessed students’ understanding of a correct experimental setup and their performance in evaluating an experiment’s results. Screens 10 through 13 are based on new, different examples of correct and incorrect experiments to make these items fair to all students (i.e., independent of the results of their experimental set up).

Results from the TIMSS 2019 field test indicated that use of a control group was one area of experimental design that was difficult for many students, and so Screen 10 was developed to probe directly into this issue. This screen presents an example of a correct experimental setup with a control tank (Tank 3) and asks students to explain why there is no fertilizer in Tank 3. As shown below, correct responses explained that a control tank provides a basis for comparing the effectiveness of each fertilizer.

Click video to play

Maximum Score Points: 1
Content Domain: Biology
Topic Area: Ecosystems
Cognitive Domain: Reasoning
Science Practice: Generating Evidence


Exhibit 51 shows that although 65 percent of Singaporean students answered correctly, 41 percent or fewer did so in the remaining countries. On average across countries, just 23 percent of students answered correctly. Across countries, girls performed better than boys by a slight margin on average (24% vs. 22%).