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

About the Task

The Pepper Plants task asked eighth grade students to design and analyze the results of an experiment testing the effectiveness of adding fertilizer to the plants’ soil and comparing the effect of two different fertilizers on pepper production. Students were asked to create their own experimental setups, which required using their knowledge of basic plant biology combined with their understanding of the principles of experimental design. Innovative response interaction spaces enabled students to control the amounts of the two different fertilizers and water supplied to each of three growth tanks containing the same number of pepper plant seedlings. As they worked through the task, students also answered a variety of multiple-choice and constructed response items. Students were requested to answer the questions in order as they worked through the task, and not to look through the investigation before starting.

Screen 1 – Pepper Plant Growth Experiment

This screen introduces the task of designing a plant growth experiment. It also orients students to the subject of the experiment by asking why fertilizer is added to growing plants. Students obtained credit if they correctly recognized that fertilizers provide nutrients that help plants grow (option A).

Click video to play

Maximum Score Points: 1
Content Domain: Biology
Topic Area: Ecosystems
Cognitive Domain: Knowing


Exhibit 40 presents the percentage of students, overall and by gender, that chose the correct response option in each country. About three-fourths of the students (78%) answered this item correctly on average across countries. On average, there essentially was no difference overall in performance between boys and girls.