Year 8 Science · Unit 4 · Lesson 3
Foundation Worksheet
Learning Goals
Match each term to its definition
Draw a line connecting each term on the left to its correct definition on the right. Or write the matching letter next to each term.
| Term | Your answer | Definition |
|---|---|---|
| Independent variable | A. The factor you deliberately change to test its effect — only one per experiment | |
| Dependent variable | B. The factor you measure or observe to see how it responds to the IV | |
| Controlled variable | C. A factor that is kept the same across all groups so it cannot affect the results | |
| Fair test | D. An investigation in which only one variable is changed while all others are held constant | |
| Validity | E. The extent to which an experiment actually tests what it claims to test |
Bonus: Give one real example of an independent variable from any experiment you have studied.
Sort it!
Each row describes a variable from one of three experiments. Write IV, DV, or Controlled in the "Type" column.
| Experiment | Variable description | Type (IV / DV / Controlled) |
|---|---|---|
| Enzyme experiment | Temperature of the water bath (changed from 10°C to 40°C) | |
| Enzyme experiment | Number of bubbles produced per minute | |
| Enzyme experiment | pH of the solution (kept at pH 7 for all trials) | |
| Plant growth | Type of fertiliser added (organic, chemical, or none) | |
| Plant growth | Height of plant measured weekly in centimetres | |
| Plant growth | Amount of water given to each plant (100 mL daily) | |
| Battery test | Brand of battery (four different brands tested) | |
| Battery test | Time (in minutes) until the device stops working |
1. What is the difference between a controlled variable and a confounding variable? Use an example in your answer.
2. A student wants to test whether temperature affects how fast sugar dissolves. Name the independent variable, the dependent variable, and one controlled variable for this experiment.
Wrap Up
In one sentence, what was the main idea of this lesson?