Working Scientifically in the Lab

Curriculum Area and Level

• Curriculum Area: Science
• Strand: Nature of Science – Investigating in Science
• Level: Level 3 (Year 7, aligned with the New Zealand Curriculum)

Big Idea:

Students will develop foundational scientific investigation skills by conducting a practical experiment on reaction rates, learning how to safely use laboratory equipment, take accurate measurements, and record observations systematically.

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Lesson Objectives

By the end of this lesson, students will:

1. Learn and follow basic laboratory safety rules.
2. Understand the scientific method and how to apply it in investigations.
3. Use laboratory equipment such as beakers, measuring cylinders, and timers accurately.
4. Conduct an experiment to investigate how temperature affects the rate of reaction between baking soda and vinegar.
5. Develop skills in recording data in a results table.

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Lesson Structure (55 min)

1. Introduction & Safety Briefing (10 min)

• Hook: Ask: Have you ever noticed how a fizzy drink reacts when you shake it? What if the temperature of the drink changes?
• Briefly introduce the concept: Chemical reactions can happen at different speeds. Today, we will investigate how temperature affects the speed of a reaction using baking soda and vinegar.
• Safety Rules Review (display on board, discuss each one):
  • Wear safety goggles and tie back long hair.
  • Always handle liquids carefully and clean up spills immediately.
  • Listen for instructions before touching any equipment.
  • No eating or drinking in the lab.

Teacher Action:

• Demonstrate the correct way to use a measuring cylinder and a timer.
• Highlight how to accurately pour liquids and measure substances.

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2. Experiment Setup - Following the Scientific Method (10 min)

1. Question: How does temperature affect the reaction rate of baking soda and vinegar?
2. Hypothesis: (Students write a prediction in science books) Example - "I think the reaction will be faster in hot water because heat speeds up reactions."
3. Materials Needed (Per Group of 4 students - 6 groups)
   • 3 small beakers (hot, cold, and room-temperature water)
   • Baking soda (1 teaspoon measured carefully)
   • Vinegar (50mL for each test)
   • Measuring cylinder (for accuracy)
   • Stopwatch
   • Stirring rod
   • Thermometer

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3. Practical Investigation (20 min)

Instructions: (Students follow a simple step-by-step guide displayed on the board)

1. Prepare three beakers

   • One with hot water (~50°C – teacher to assist).
   • One with cold water (from the fridge).
   • One at room temperature.

2. Dissolve 1 teaspoon of baking soda in each beaker.

3. Simultaneously pour 50mL vinegar into each beaker while starting the stopwatch.

4. Observe and measure:

   • How long does it take for the bubbles to stop?
   • Which reaction was fastest?
   • Write observations in a results table.

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4. Recording & Discussion (10 min)

• Results Table (Students Copy & Complete in Books):

Temperature of Water	Reaction Time (Seconds)	Observations (e.g. bubble size)
Cold Water (~5°C)
Room Temperature (~20°C)
Warm Water (~50°C)

Discussion Questions (Whole-Class Reflection):

• What pattern did we notice?
• Did your hypothesis match the results?
• What are the logical reasons for this result?
• How could we improve our measuring accuracy in future experiments?

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5. Conclusion & Clean-up (5 min)

• Wrap up the lesson by asking students: Why might temperature matter in real-world reactions (e.g. cooking, rusting, digestion)?
• Encourage curiosity: What other factors could affect reaction speed?
• Students help clean up and return equipment neatly.

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Assessment & Next Steps

• Formative Assessment:

  • Observing if students follow safety procedures.
  • Checking individual results tables for accuracy.
  • Assessing student participation in discussion.

• Next Lesson: Building on Scientific Thinking

  • Exploring variables in experiments (e.g. Changing vinegar amounts).
  • Learning graphing skills to represent reaction times visually.

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Teacher Notes & Adaptations

• For more challenge: Introduce the concept of catalysts by adding dish soap to one reaction and noting any changes.
• For extra support: Assign students mixed-ability roles (timekeeper, recorder, observer).
• For cultural relevance: Discuss mātauranga Māori and how traditional knowledge incorporates observing natural processes (e.g. fermentation, hangi cooking times).

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Why This Lesson is Effective

• Engaging: Hands-on, practical, and fosters curiosity.
• Aligned with NZ Curriculum: Develops scientific investigation skills.
• Scaffolded for Success: Introduces beginners to lab work safely and progressively.

This lesson is designed to equip Year 7 students with foundational skills in the scientific method, lab safety, and data recording, setting them up for success in future experiments. 🚀 🌿 🔬