The scientific method

👩 Teacher’s Guide

🎯 Objective

Students will be able to:

Describe the steps of the scientific method and why each step matters
Identify independent, dependent, and control variables in an investigation
Write a testable hypothesis that can be supported or refuted by evidence

📝 Teaching Notes

Key idea to emphasize: Main concept: evidence-based investigation with a fair test.
Common misconception: Misconception: a hypothesis is a 'guess' rather than a testable explanation.
Suggested teaching approach:
- Model the cycle: question → hypothesis → method → results → conclusion → review.
- Use a simple example (e.g., paper towel absorbency) to map each step.
- Emphasize changing ideas when evidence changes.

💬 Discussion Starter

Ask students:

Why is evidence more important than opinion in science?
What makes an experiment a “fair test”?
How can scientists disagree and still make progress?

🧒 Student Worksheet

Concept and Helping Material

Scientists use the scientific method to answer questions with evidence. A good investigation starts with a clear question, uses a fair test, collects data carefully, and ends with a conclusion that matches the results.

Vocabulary and Definitions

— A testable explanation that can be supported or refuted by evidence.
— A factor that can change in an investigation.
— A factor kept the same to make a fair test.
— Measurements or observations collected during an investigation.
— A statement answering the question using the results.

Hands-On Experiment or Activities

Activity 1: Paper Towel Absorbency Test
What You Need: paper towels (2 brands), water, cup, tray, stopwatch, ruler.
What You Do: Cut equal-size strips, dip each strip for 5 seconds, measure wet length after 30 seconds; repeat 3 times per brand.
Think and Talk: What changed? What stayed the same?

Activity 2: Seed Germination Fair Test
What You Need: seeds, cotton wool, water, 3 cups, labels, light source.
What You Do: Change only one factor (e.g., light vs dark) while keeping water and temperature the same; count sprouted seeds after 5 days.
Think and Talk: What changed? What stayed the same?

Practice Questions (QA)

What is the purpose of a hypothesis in an investigation?
Name the variable you change on purpose.
Name the variable you measure or observe.
Why keep control variables the same?
What does it mean to repeat trials?
Why record results in a table during the experiment?
If results do not support the hypothesis, what should a scientist do?
What is an anomaly?
What is the difference between observation and inference?
Why is peer review useful?

Reflection

How could the scientific method help you make a better decision in real life?
What is one habit you can practice to improve your scientific thinking?