Ontario Grade 9 Science Class Practice Exam 2026 - Free Grade 9 Science Practice Questions and Study Guide

The term "variable" in an experiment refers to any factor that can change to test its effect on another variable. In scientific experiments, variables are crucial for understanding relationships between different factors. Typically, variables can be categorized as independent variables, which are changed or manipulated to observe their effects, and dependent variables, which are measured to see how they respond to the changes in the independent variable.

Recognizing the role of variables helps scientists design their studies appropriately. For example, if you're testing how sunlight affects plant growth, the amount of sunlight would be the independent variable that you change, while the height of the plants would be the dependent variable that you measure. This relationship allows for the determination of causation and helps validate scientific hypotheses.