Measuring & Plotting Lengths
Generate measurement data by measuring lengths to the nearest whole unit and display the data on a line plot
What a learner can do afterwards
- Measure the lengths of several objects and record the data
- Create a line plot with a horizontal scale marked in whole-number units
- Interpret a line plot to answer questions about the data
- Find the total measured length by adding recorded lengths in the same unit.
1 · Read
Place one end of each object at the ruler's zero mark and read the other end. For this activity, record the nearest whole centimetre. Pick the whole number closest to the end. Write every measurement with its unit in a list or table. To find total length, add the recorded lengths.
Zoe's acorn lengths, rounded to whole centimetres, are 4, 5, 4, 6, 5. She draws equally spaced whole-number ticks and labels the unit as centimetres. Above 4, she stacks two X's; above 5, two X's; above 6, one X. Each X is one acorn. A length with no acorns keeps its tick but gets no X.
Count the X's above a length to find how many objects have that measurement. A taller stack means more objects. To find the number of objects altogether, add the counts from every stack. Do not add the length labels when the question asks how many objects.
Measure each object to the nearest whole unit, write it down, then stack one X above its number on a line plot to see the whole pattern at a glance.
More to read
Key ideas: create and analyze a line plot for measurement data to the nearest half unit and quarter unit
A line plot turns measurements into a picture. Choose evenly spaced ticks that match the recorded units: whole centimetres for whole-centimetre data, or fractional steps for finer measurements. Stack one cross for each observation above its value. The tallest stacks show the most common values.
Practice with Line Plots
Plotting has three moves: measure, record, then plot. Measure each object with the zero lined up, and write every length in a table. Then move each table entry onto the plot as a cross. Rushing to plot before recording causes lost data.
Button Diameters
Real data is messy, and plots tame it. Measuring a handful of buttons gives a spread of diameters to record. Each measurement becomes one cross above its size on the scale. Clusters show the usual size, and lonely crosses show the odd ones out.
Length review
Every plotted length needs measuring well first. Pick centimetres for pencils and sticks, line up zero, and read carefully. Record each result with its unit before touching the plot. A line plot is only as honest as its measurements.
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2 · Watch
به انگلیسیTake it off screen
Where it sits
Learn first
Optional connections
Where this leads
17 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.