Scientific Investigations

Year 12 Science – Lesson 1 of 8 in Biology Investigation Mastery

Lesson Title: Introduction to Scientific Investigations

Curriculum Area: NCEA Level 2 Science – Biology

Achievement Objective: This lesson aligns with the New Zealand Curriculum's Science strand: Nature of Science – Investigating in Science. Students will:

• Develop an understanding of scientific investigations and the principles of fair testing.
• Learn to identify independent and dependent variables.
• Construct a meaningful, testable hypothesis.

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Lesson Overview

This lesson introduces the essential principles of scientific investigations, emphasising fair testing. Students will explore the roles of independent and dependent variables and understand how to formulate a valid scientific hypothesis. Through interactive hands-on activities, students will engage in authentic scientific inquiry aligned with NCEA expectations.

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Lesson Breakdown (60 Minutes)

1. Engagement & Warm-Up (10 min)

• Activity: Scientific Curiosity Icebreaker – Present a simple but intriguing real-world scenario to spark curiosity. Example: What makes bread rise? Show two pieces of bread: one toasted and another fresh. Ask, "What changed, and why?"
• Expected Response: Encourage students to think critically. Guide them to realise that temperature (independent variable) affects the outcome (dependent variable).
• Discussion: Briefly explain that scientists investigate such questions by testing variables systematically.

2. Explanation & Guided Discussion (15 min)

• Key Concept 1: The Importance of Fair Testing

  • Define and illustrate fair testing using relatable examples such as baking, plant growth, and sports performance.
  • Highlight why changing one variable at a time ensures reliable results.

• Key Concept 2: Independent vs Dependent Variables

  • Independent Variable (IV) – The factor that is changed in an experiment.
  • Dependent Variable (DV) – The factor being measured or observed.
  • Provide real-world examples: Does caffeine affect heart rate? (IV = caffeine intake, DV = heart rate).

• Key Concept 3: Formulating a Scientific Hypothesis

  • Explain the format: If [independent variable] changes, then [dependent variable] will change because [scientific reasoning].
  • Example: If the temperature increases, then the amount of carbon dioxide produced by yeast will increase because enzymes work more efficiently at higher temperatures.

3. Hands-on Activity – Mini-Investigation (20 min)

• Scenario: "How does light affect seed germination?"

• Materials: Dry seeds, cotton wool, two petri dishes, and a light source.

• Step-by-Step Investigation:

  1. Divide seeds into two groups: one placed in a dark cupboard, the other under light.
  2. Predict the outcome (light exposure vs seed germination).
  3. Identify IV (light exposure) and DV (seed germination).
  4. Discuss controlled variables (water, temperature, seed type).
  5. Write a hypothesis using the correct format.

• Class Discussion: Ask students how they could improve reliability (e.g., repeating the experiment, using more seeds).

4. Reflection & Wrap-Up (10 min)

• Think-Pair-Share: Pose the question: Why does fair testing matter in the real world? (Consider medicine, agriculture, or climate science).
• Exit Slip: Have students write a hypothesis for a new question: How does salt affect plant growth?

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Assessment & Homework

• Formative Assessment:

  • Observe participation in discussions and the accuracy of student hypotheses.
  • Check understanding through exit slips.

• Homework Task:

  • Research and bring an example of a scientific investigation found in the news (e.g., climate change studies, medical trials).
  • Identify the IV, DV, and hypothesis used in that study.

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Teacher Notes & Differentiation

• For Advanced Learners: Encourage them to consider multiple variables or formulate a controlled experiment with a null hypothesis approach.
• For Students Needing Support: Provide sentence starters for hypothesis writing and use visual aids to reinforce concepts.

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Why This Lesson Works

• Engaging & Relatable: Uses real-world examples to make science relevant.
• Hands-On & Inquiry-Based: Encourages active participation.
• Aligned with NCEA Expectations: Builds foundational skills for scientific investigations in Level 2 Biology.

Next Lesson: Designing a Controlled Experiment

Students will build on today’s lesson by outlining and planning their own simple investigation.