
Eggs, Apples and Centimetres – Transformation of units
Students study concrete materials to measure 1D, 2D and 3D quantities
Key Focus
Transforming units
Subject(s)
Physics, Mathematics
Suitable for age(s)
10-18 years
Introduction
This task provides students with a practical opportunity to deepen their understanding of units and unit transformations in mathematics and physics. It highlights the importance of using correct units, introduces SI prefixes, and helps students gain confidence in converting 1D, 2D, and 3D measurements using unit prefixes and base units. Through guided inquiry and collaborative activities, students develop the essential skills needed for correct and automatic handling of units in science and mathematics problem-solving.
Units are introduced into the school curricula for the first time during mathematics lessons on measuring distance. Later, in mathematics lessons, students also learn about units for area and volume. A proper introduction to these concepts in math should help students (1) understand why units are essential in all measurements and calculations in physics and (2) develop automatic skills in converting units using prefixes. They should also realise that complex units can be broken down into a few basic units. Teachers often report that many students struggle to understand the meaning of units and find it challenging to develop the skills needed to convert units, both using unit prefixes and base units. In early mathematics lessons, students initially perform calculations using only numbers. When dealing with simple measurements of distance, time, temperature, and other quantities, students often overlook units when presenting their results or solving word problems. Therefore, it is essential that, from the beginning, both mathematics and science teachers emphasise the importance of including units whenever appropriate. The task is designed to address these issues in a few steps that can be applied in both mathematics and physics lessons.
Task Description
This task introduces semi-quantitative comparison and teaches students to develop procedures that enable assigning a numerical value to properties of objects or phenomena. While most This task consists of two parts. The first part is a brief inquiry activity that involves measuring the dimensions of objects found in the classroom. The second part begins with building real paper objects and utilising them in 1D, 2D, and 3D environments. The subsequent step in the second part involves calculations using unit prefixes in 1D, 2D, and 3D, as well as other units.
- Part 1: A structured inquiry-based learning (IBL) activity in which students explore measurements using standard tools, practice using unit prefixes (milli-, centi-, deci-), and develop correct multiplication notations for area and volume.
- Part 2: A group problem-solving task in which students construct and fill large squares and cubes to reinforce spatial understanding of unit powers. They then use these physical models to perform unit transformations across dimensions (e.g., from cm² to m², or from cm³ to dm³).
This task can be implemented regularly, initially in mathematics classes and later in physics classes, until students develop their habits of (1) using units in all calculations related to measurements, (2) correctly transforming units with the use of unit prefixes, and (3) accurately transforming the powers of units with the use of unit prefixes. The task is suitable for on-site classes. The second part can be taught in person or adapted for remote learning, utilising breakout rooms. The two parts can be used on different occasions:
⮚ Part 1 – as an introduction to distance, area, and volume measurements in mathematics.
⮚ Part 2 – as an introduction to the transformation of units in 1D, 2D, and 3D in mathematics classes and in physics classes
⮚ Part 2 (points 4-7) – repeatedly, on different occasions in physics and mathematics classes, as an algebra exercise building the automatism of proper transformation of units with the use of unit prefixes.
Materials required
For part 1 :
- Rulers, meter sticks
- Measuring tools marked in mm, cm, dm
- Regular classroom objects (boxes, books, etc.)
- Worksheet with units and prefixes (dm, cm, mm, mA, mJ, etc.)
- Scissors, glue, coloured paper for making squares and cube templates
For part 2 :
- Pre-cut squares (1 cm² and 1 dm²) and cubes (1 cm³ and 1 dm³) made of sturdy paper (200 g/m² or more)
- Materials for building cube and square shells (wooden or plastic sticks, wires, or similar)
- Additional worksheets with calculations involving SI units and prefixes
- Digital collaboration tools (e.g., Jamboard, Google Drive, OneNote Miro, Mural, etc.)) if online.

