Non-standard Unit Measurement

Non-standard units are ordinary objects which are used because they are known to students and are readily available, for example, paces for length, books for area and cups for volume. Students should be provided with many opportunities to measure using these kinds of non-standard units. Non-standard units introduce the students to the use of units to provide numbers that describe a measure outcome, for example, the desk is 4 handspans across. Non-standard units introduce most of the principles associated with measurement:

• ·         Measures are expressed by counting the total number of units used.
• ·         During a measurement activity, the unit must not change.
• ·         Units of measure are not absolute but are chosen for appropriateness. For example, the length of the room could be measured by handspans but a pace is more appropriate.

Prior to introducing standard units, students need to realise that non-standard units tend to be personal and are not the most suitable for communication. For example, my hands are smaller than yours, so telling me to measure a piece of cloth three hands wide may not be useful.