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Scientific Enquiry - Recording data using tables and bar charts

Grade 4IGCSE

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

🔑Concepts

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Scientific data is information collected during an investigation, often through measurements using units such as centimeters (cmcm), grams (gg), or milliliters (mlml).

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A results table is used to organize data clearly. The independent variable (what you change) is usually placed in the left-hand column, and the dependent variable (what you measure) is placed in the right-hand column.

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Table headings must include the name of the variable and the unit of measurement, separated by a slash or brackets, such as Mass/gMass / g or Time(s)Time (s).

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Bar charts are used to display discrete data (data that fits into categories). Each bar must be the same width, and there should be equal gaps between the bars.

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The yy-axis (vertical axis) of a bar chart shows the frequency or measurement and must have a consistent scale, such as counting in 2s2s, 5s5s, or 10s10s.

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The xx-axis (horizontal axis) of a bar chart shows the categories or the independent variable labels.

📐Formulae

Table Heading=Variable Name/Unit\text{Table Heading} = \text{Variable Name} / \text{Unit}

Y-axis Scale Interval=Maximum ValueNumber of Segments\text{Y-axis Scale Interval} = \frac{\text{Maximum Value}}{\text{Number of Segments}}

Value on Scale=Number of increments×Scale step value\text{Value on Scale} = \text{Number of increments} \times \text{Scale step value}

💡Examples

Problem 1:

A student measures the height of four different plants after two weeks. Plant A is 1212 cmcm, Plant B is 1515 cmcm, Plant C is 99 cmcm, and Plant D is 1818 cmcm. How should this data be recorded in a table?

Solution:

Create a table with two columns: 'Plant ID' and 'Height (cmcm)'. The rows would be: | A | 1212 |, | B | 1515 |, | C | 99 |, and | D | 1818 |.

Explanation:

The units (cmcm) are placed in the header so they do not need to be repeated in every cell of the table.

Problem 2:

In a bar chart showing the number of insects found in a garden, the yy-axis scale goes up in steps of 55 (0,5,10,15...0, 5, 10, 15...). If the bar for 'Bees' reaches exactly halfway between 1010 and 1515, what is the total count of Bees?

Solution:

12.512.5 (or 1212 or 1313 depending on if the data must be a whole number). Usually, in Grade 4, students identify the midpoint as 10+152=12.5\frac{10 + 15}{2} = 12.5.

Explanation:

To find the value between two scale markings, you calculate the midpoint between the lower and upper number.

Problem 3:

Identify the error in a bar chart where the bars for 'Monday' and 'Tuesday' are touching, but there is a large gap between 'Tuesday' and 'Wednesday'.

Solution:

The gaps between the bars are inconsistent.

Explanation:

In a scientific bar chart for discrete categories, the spacing between bars should be equal to ensure the data is not misrepresented visually.