Illustrative Examples of Units of Practice

The Oak Island Money Pit: Building a Model


For over 200 years, people have been searching for buried treasure in a booby-trapped site on Oak Island off the coast of Nova Scotia. Six people have died and millions of dollars have been spent trying to solve the mystery of the "Money Pit", with no success. In this cooperative activity, students will use ratio and proportion to create a scale model of the Oak Island Money Pit. The story of the Oak Island mystery can grab the attention of students and provide an incentive for them to work on their scale model.

Subjects: Math, Science

Learning Levels: Grades 4-8

Author(s): Lawrence Rigby


Most middle school students do not usually use ratios in their daily lives. In this activity, students will be asked to work in a small group to build a proportional model of the Oak Island Money Pit. Through this hands-on, cooperative approach students will extend their number and operation skills by using and interpreting ratio, proportion and scale.


Students in this group activity will have an opportunity to calculate with fractions and to solve problems involving proportions. They will understand the relationship between a scale drawing and a scale model, and will experience various methods of calculating and using ratios.


The estimated time for this activity is five 40 minute periods

The students will be asked to work cooperatively in groups of 2 or 3. The project will begin with an introduction to the Mysteries of the Oak Island Treasure. With access to the Internet, students will visit a designated site to obtain data and measurements to guide their model building. If there are a limited number of computers available, the teacher will need to plan for individual group access.

Students may need assistance converting the measurements to metric. While many students will understand how to express a ratio as a fraction, they may need help in applying ratios to creating a scale drawing and a scale model.

An extension question on volume is included.


Before starting this activity, the teacher should visit the Internet site at:

Start by showing a video or reading a book on the Mystery of Oak Island. Direct students to the web site as well. Use the story to create enthusiasm and interest among the students.

Indicate to the students that, in groups, they are going to create a physical scale model of the Oak Island money pit. Talk about scale models and develop the idea of using a ratio to determine the measure of a physical model from a scale drawing.

Ask the students to go to the web page, capture the diagram of the pit and trace or draw the diagram on graph paper. They should include all measurements.

Once they have completed their diagram, they need to convert the imperial measurements into metric. Some students may need a brief explanation of how to do the conversations. They can be encouraged to use calculators or spreadsheets for this task.

With an accurate diagram ready, students can begin to build a scale model of the pit. They need to decide what to use for their model, several 1 litre milk cartons, spaghetti boxes taped together, or some other material.

The size of their box will determine the scale to use to convert from their diagram to the actual cardboard model. The width of the box will be an important measurement to find the heights in the "pit." Once they have discovered their scale they can use it over and over again to build the platforms in the proper spots.

The students should label the platforms with their depths, and put other markings on the model so that it matches the actual "money pit."

Have groups present their model to other groups and ask them to check their scale and measurements for accuracy.


In this cooperative group activity, students need to be encouraged to work well together, to listen to each other, and to respect each others work. Individual jobs can be assigned within the group by group members, or by teacher interventions when necessary. All members of the group should be involved in the ratio calculations and the measurements, so that each student can understand the math concepts. Individual creativity with group agreement should be encouraged.


1) Teacher observations: did the students demonstrate the ability to use ratio and proportion to create an accurate scale.

2) Students from other groups will check the models to see if they used the correct scale and if their measurements are correct.

3) Rubric: you can make your own rubric for the project at:


1) video, article or book on the Oak Island Money Pit

2) Boxes (different boxes of various dimensions)

3) glue

4) materials to make the platforms (spaghetti, straws, coffee stir sticks, cardboard)

5) paint for the platforms - ex. the wooden platform can be brown

6) scissors


If you decide to complete this project with your students I would love to receive some pictures of their money pits. You can send them to and I will publish them as an attachment to this page. I hope to have pictures of my student's money pits attached to this site as well.

Extension question:

Ask the students to go back to the Oak Island web site and to use the information there to find the volume of water that entered the pit when it flooded. They can then use ratio and proportion to find out how much water they would have to add to their model to flood.


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