It could be used in a variety of introductory geoscience courses or with middle-school or high-school students. I have tested it in geoscience courses for pre-service teachers (junior and senior education majors).

Students will need to be able to measure, and have a rough concept of proportionality.

This project has been assigned as homework.

Review or learn about some of the major events in Earth history
Observe that the major events with which we are familiar and consider important are generally clustered close to the present
Learn that many of the older layers in the rock record are harder for us to retrieve or to understand than the newer ones

Proportional reasoning
The use of analogy
Pattern-recognition (and explanation)

Drawing timelines to scale

For this homework assignment, students have to draw two scaled timelines. The first is a personal timeline. They need to come up with the events themselves, an easy task that will build confidence for student who are intimidated by science and math. Following guidelines, they decide on a scale, and draw a linear timeline on which they plot their chosen events. Most students will primarily include recent events. They are asked to identify and explain any patterns in their timeline. Students should note the clustering at the present, and describe the emphasis on the present as resulting from memory, relevance to future hopes and worries, etc.

The second timeline is more traditional. The students are given 16 Earth history events with dates and asked to draw another timeline, using the procedure from the personal timeline, but the line is already drawn for them. They will probably recognize most of the events on the list, and will be keeping them in order and spacing them out on the timeline. They are once again asked to identify and explain patterns and should recognize the emphasis on the present. This time, availability of fossils/rocks and relevance to current conditions and problems are good answers.

From an assessment perspective, the most important thing is for the students to notice the way that events cluster on both timelines, and to create parallel explanations for that clustering.

After the first few classes, the assignment was graded based on completeness, and adherence to directions (the introduction of grading increased the proportion of timelines actually drawn to scale).

A similar project, emphasizing different levels of scaling, is the Hierarchical Alignment of Timelines activity