Identify the Purpose of the Experiment
Sample Question:
What was the main purpose of Experiment 2?
What’s Being Tested: Your ability to understand why the experiment was done — what concept or relationship it was designed to test.
Knowledge & Skills Required:
- Reading the introduction and procedure
- Understanding the difference between testing, controlling, and observing
- Recognizing experimental goals (e.g., "to test if pH affects rate")
What’s Needed to Answer Correctly:
- Focus on experimental intent, not data results
- Don't confuse goals with outcomes
Correct Approach:
- Read the description of Experiment 2 carefully
- Identify what variable was manipulated
- Ask: “What were they trying to find out?”
Identify Independent, Dependent, and Controlled Variables
Sample Question:
Which variable was manipulated in the experiment? Which was measured as the dependent variable?
What’s Being Tested: Understanding of how the experiment was structured, especially in terms of variable roles.
Knowledge & Skills Required:
- Definitions:
- Independent: What the experimenter changes
- Dependent: What is measured
- Controlled: What’s kept constant
- Matching these to real-world chemistry (e.g., "acid concentration" vs. "reaction time")
What’s Needed to Answer Correctly:
- Be able to distinguish clearly between input and outcome variables
Correct Approach:
- Ask: What was changed across trials? → Independent
- Ask: What was measured as a result? → Dependent
- Identify values that were held the same → Controlled
Evaluate or Modify the Experimental Design
Sample Question:
Which of the following changes would most improve the reliability of the experiment?
What’s Being Tested: Your ability to recognize good experimental design, including what makes it stronger or weaker.
Knowledge & Skills Required:
- Experimental best practices:
- Large sample sizes
- Consistent measurements
- Avoiding confounding variables
What’s Needed to Answer Correctly:
- Identify flaws or limitations
- Suggest or recognize improvements that increase validity or reliability
Correct Approach:
- Consider what might introduce inconsistency or error
- Choose the change that most directly improves control or precision
Understand the Reason for Including a Control Group or Trial
Sample Question:
Why was distilled water used in Trial 1?
What’s Being Tested: Your understanding of the function of a control condition.
Knowledge & Skills Required:
- What a control is: a baseline with no active treatment
- In chemistry: often using distilled water, 0 M concentration, no catalyst, etc.
What’s Needed to Answer Correctly:
- Know that controls are used for comparison, to isolate effects of the independent variable
Correct Approach:
- Identify what variable the control lacks
- Explain how this helps in interpreting differences in the results
Predict the Effect of a Change in Setup
Sample Question:
If the amount of catalyst were doubled, how would the reaction time likely change?
What’s Being Tested: Whether you understand causal relationships between variables in the setup — even if the specific change wasn’t tested.
Knowledge & Skills Required:
- Understanding basic chemical behavior (e.g., catalysts speed up reactions)
- Recognizing direct/indirect effects of changes
What’s Needed to Answer Correctly:
- Apply logical reasoning based on the experiment’s structure and purpose
- Avoid outside chemistry knowledge unless directly supported by passage logic
Correct Approach:
- Review the pattern shown in the original data
- Extend the trend logically using reasoning like: “Doubling catalyst increased rate before, so more should increase it further”
Distinguish Between Multiple Experiments
Sample Question:
Which of the following best describes the difference between Experiment 1 and Experiment 2?
What’s Being Tested: Your ability to compare how two related experiments were structured differently, and what each was testing.
Knowledge & Skills Required:
- Understanding of each experiment’s setup, independent variable, and measured outcome
- Awareness of what changed between them
What’s Needed to Answer Correctly:
- Recognize what was varied in each design (e.g., temperature in one, pH in another)
- See how their purposes or variables differ
Correct Approach:
- Summarize each experiment’s key features
- Compare their independent variables and goals
- Choose the answer that best captures the distinct experimental focus
Infer the Researcher’s Reasoning
Sample Question:
Why did the researchers increase the temperature by 10°C increments instead of 2°C?
What’s Being Tested: Can you understand the practical or logical reasons behind a design choice?
Knowledge & Skills Required:
- Knowing that larger increments can show clearer trends
- Understanding trade-offs in experimental detail and time
What’s Needed to Answer Correctly:
- Recognize the goal of making patterns easier to detect or more time-efficient
Correct Approach:
- Consider why the scientist would prefer that setup
- Eliminate options that ignore practical design goals (e.g., sensitivity, efficiency)