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Scientific Inquiry and Skills - Data Collection and Graphing

Grade 6IB

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

🔑Concepts

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Variables: In a scientific investigation, the Independent Variable is the factor changed by the scientist (xx-axis), the Dependent Variable is the factor being measured (yy-axis), and Control Variables are kept constant to ensure a fair test.

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Quantitative vs. Qualitative Data: Quantitative data involves numerical measurements and units, such as 25.5 cm25.5 \text{ cm} or 10.2 s10.2 \text{ s}. Qualitative data involves descriptive observations, such as 'the solution turned blue'.

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SI Units: Standard units of measurement include meters (m\text{m}) for length, kilograms (kg\text{kg}) for mass, seconds (s\text{s}) for time, and degrees Celsius (∘C^\circ\text{C}) for temperature.

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Graphing (SLAP): A good graph must have a Scale (consistent intervals), Labels (including units like Distance (m)\text{Distance (m)}), Axes (correctly assigned), and Points (accurately plotted).

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Line of Best Fit: A smooth line or curve that represents the general trend of the data points, rather than connecting them 'dot-to-dot'.

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Accuracy and Precision: Accuracy refers to how close a measurement is to the true value, while Precision refers to how close repeated measurements are to each other.

📐Formulae

Average (Mean)=∑Total sum of valuesNumber of trials\text{Average (Mean)} = \frac{\sum \text{Total sum of values}}{\text{Number of trials}}

Range=Highest Value−Lowest Value\text{Range} = \text{Highest Value} - \text{Lowest Value}

Density (ρ)=mass (m)volume (V)\text{Density (}\rho\text{)} = \frac{\text{mass (m)}}{\text{volume (V)}}

Percentage Error=∣Measured Value−Accepted ValueAccepted Value∣×100%\text{Percentage Error} = \left| \frac{\text{Measured Value} - \text{Accepted Value}}{\text{Accepted Value}} \right| \times 100\%

💡Examples

Problem 1:

A student measures the time it takes for a ball to roll down a ramp in three trials. The results are 2.4 s2.4 \text{ s}, 2.6 s2.6 \text{ s}, and 2.5 s2.5 \text{ s}. Calculate the average time.

Solution:

Average=2.4 s+2.6 s+2.5 s3=2.5 s\text{Average} = \frac{2.4 \text{ s} + 2.6 \text{ s} + 2.5 \text{ s}}{3} = 2.5 \text{ s}

Explanation:

To find the average, sum all the individual measurements and divide by the total number of trials conducted.

Problem 2:

Identify the independent and dependent variables: A scientist studies how the amount of sunlight (0 to 10 hours0 \text{ to } 10 \text{ hours}) affects the growth height of a plant (measured in cm\text{cm}).

Solution:

Independent Variable: Amount of sunlight (hours). Dependent Variable: Growth height (cm\text{cm}).

Explanation:

The scientist chooses to change the amount of sunlight (Independent), and the plant's height changes as a result (Dependent).

Problem 3:

Determine the density of a cube that has a mass of 54 g54 \text{ g} and a volume of 20 cm320 \text{ cm}^3.

Solution:

ρ=54 g20 cm3=2.7 g/cm3\rho = \frac{54 \text{ g}}{20 \text{ cm}^3} = 2.7 \text{ g/cm}^3

Explanation:

Using the formula for density ρ=mV\rho = \frac{m}{V}, we divide the mass by the volume to get the density in g/cm3\text{g/cm}^3.

Data Collection and Graphing - Revision Notes & Key Formulas | IB Grade 6 Science