Measuring length (age 10+)
Recognise volume as an attribute of solid figures; understand that a unit cube (side length 1 unit) has 'one cubic unit' of volume and can be used to measure volume; a solid packed with n unit cubes has volume n cubic units
What a learner can do afterwards
- Explain what 'volume' means for a 3D shape and how it differs from area
- Identify a unit cube and explain that it represents one cubic unit of volume
- Determine the volume of a small solid by counting the unit cubes that fill it
The lesson
Volume tells you how much space a solid shape fills. It is different from area, which measures a flat surface, like the top of a desk. To measure volume, you use a small cube called a unit cube.
Mia builds a block from unit cubes. She stacks two layers, with 4 cubes in each layer. She counts them all: 4 in the bottom layer, 4 in the top layer, 8 in total. Her block has a volume of 8 cubic units.
When a solid has a strange shape, just count every unit cube packed inside it. It does not matter how the cubes are arranged. Each cube always adds one cubic unit to the total volume.
Volume is the space inside a 3D shape, and you measure it by counting unit cubes, each one cubic unit.
Watch it
Where it sits
Learn first
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Where this leads
8 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.