A container which held 1000 coloured paperclips had an unknown number removed. The task is to determine how many paperclips remain without counting them.

The video Paperclip Investigation demonstrates the process.


You can download the Paperclip Investigation video transcript.


In the Paperclip Investigation: Student Worksheet, students are introduced to a tag-release-recapture method used by scientists to determine the size of wild populations. You can also download Paperclip Investigation Work Sample.

Students place 100 silver paperclips into the container of coloured paperclips and shake to distribute them evenly. They draw random samples from the container. The proportion of silver clips in the sample is expected to be the same as the proportion of silver clips in the container. Knowing that there are 100 silver clips, enables students to gain an estimate for the total number of clips in the container.

This investigation is appropriate for students from years 7 to 9.

Curriculum links

Year 8: Explore the variation of means and proportions of random samples drawn from the same population