This open-ended mathematics investigation has been designed to deepen students’ understanding of time.

In this investigation, the students create a sand timer out of a small plastic container and some sand. Their timer must run as close to one minute as possible.

The students have three chances to make the sand run through their timer in exactly one minute. After each attempt, they may make adjustments to their timer, e.g. making the hole at the bottom of the container bigger or smaller, adding more sand, or using less sand.

A table is provided for the students to record the amount of time it takes for the sand to run through their timer during each attempt, and to record any adjustments they make before trying again!

This teaching resource includes:

•  teacher notes, detailing a range of important information about the investigation
• a detailed description of the investigation for students, including step-by-step instructions
• a recording worksheet
• reflection questions.