Physical Science · Science Practices
Scientific Method: Ask, Test, Measure & Explain
Turn a question into a fair test, change one variable, collect repeated data, and use evidence to explain what the results support.

Lesson plan
Scientific Method: Ask, Test, Measure & Explain
A step-by-step guide to help you teach this lesson.
Plan with confidence
Lesson overview
What students will learn
- Recognize a testable science question and identify the variable being changed.
- Plan a fair investigation by keeping important conditions the same and repeating trials.
Key science ideas
- A testable question can be answered with observations or measurements.
- In a fair comparison, scientists change one important variable and keep other important conditions the same.
- Repeating trials helps show whether a result is consistent or unusual.
Lesson at a glance
- Grade 3
- 45 min
- ~12 min prep
- 5 materials
What’s included
- Lesson Plan
- Investigation
- Teacher Slides
- Printable Worksheet
- Teacher Answer Key
- Interactive Activity
- Vocabulary