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Scientific Inquiry and Skills - The Scientific Method

Grade 6IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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The Scientific Method is a systematic process used by scientists to explore observations and answer questions. It typically follows a sequence: Observation, Question, Hypothesis, Experiment, Data Analysis, and Conclusion.

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A Hypothesis is a testable prediction, often written in the format: 'If the Independent VariableIndependent~Variable is changed, then the Dependent VariableDependent~Variable will respond in this way, because...'

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Variables are critical in any experiment: The Independent Variable (IV)Independent~Variable~(IV) is the factor you change, the Dependent Variable (DV)Dependent~Variable~(DV) is the factor you measure, and Controlled VariablesControlled~Variables are factors kept constant to ensure a fair testfair~test.

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Data collection can be Quantitative (numerical measurements like 15.5 g15.5~g or 10 mL10~mL) or Qualitative (descriptive observations like 'the solution turned blue').

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Reliability in scientific inquiry is improved by repeating trials and calculating the mean, while Validity refers to how well the experiment actually tests the intended hypothesis.

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The SI unit system is used for consistency in measurements, such as meters (m)meters~(m) for length, kilograms (kg)kilograms~(kg) for mass, and seconds (s)seconds~(s) for time.

📐Formulae

Mean (Average)=∑valuesn\text{Mean (Average)} = \frac{\sum \text{values}}{n}

Density(d)=mV\text{Density} (d) = \frac{m}{V}

Speed(v)=ΔdΔt\text{Speed} (v) = \frac{\Delta d}{\Delta t}

Percentage Change=New Value−Old ValueOld Value×100%\text{Percentage Change} = \frac{\text{New Value} - \text{Old Value}}{\text{Old Value}} \times 100\%

💡Examples

Problem 1:

A student investigates how the amount of fertilizer affects the height of a plant. They use three plants: Plant A receives 0 g0~g, Plant B receives 5 g5~g, and Plant C receives 10 g10~g of fertilizer. Identify the IVIV, DVDV, and two controlled variables.

Solution:

The IVIV is the amount of fertilizer (gg). The DVDV is the height of the plant (cmcm). Controlled variables include the type of plant and the amount of water (mLmL) provided daily.

Explanation:

The independent variable is the one manipulated by the researcher. The dependent variable is the outcome measured. Controlled variables must stay the same to ensure the results are caused only by the IVIV.

Problem 2:

During an experiment, a student records the temperature of water as 22 ∘C22~^{\circ}C, 24 ∘C24~^{\circ}C, and 23 ∘C23~^{\circ}C across three trials. Calculate the average temperature.

Solution:

Average=22+24+233=23 ∘C\text{Average} = \frac{22 + 24 + 23}{3} = 23~^{\circ}C

Explanation:

The mean is calculated by summing all data points and dividing by the total number of trials (n=3n = 3).

Problem 3:

Is the following a valid hypothesis? 'If I add more sugar (C12H22O11C_{12}H_{22}O_{11}) to water, it will taste better.'

Solution:

No, this is not a strong scientific hypothesis.

Explanation:

A hypothesis must be objective and measurable. 'Tasting better' is a subjective opinion (Qualitative) and difficult to measure accurately. A better hypothesis would be: 'If the mass of sugar (gg) increases, then the boiling point (∘C^{\circ}C) of the solution will increase.'

The Scientific Method - Revision Notes & Key Formulas | IB Grade 6 Science