Posts Tagged With: timeline

Historical Geology Timeline Activity

Some time ago I dreamed about the perfect tool for teaching historical geology. It would be an interactive timeline that students could update with events, and it would even have the ability to allow students to quiz themselves.

While that tool has yet to materialize, I did come up with a low-tech solution that permits the plotting of geological events that occur over widely varying timescales. I created four timeline forms to fit 8.5” x 11” paper. The forms cover different intervals and scales of geological time. They are:

  • Timeline 1: The Precambrian (4.5 billion years to 0.5 billion years ago
  • Timeline 2: The Paleozoic Era (540 million years to 250 million years ago)
  • Timeline 3: The Mesozoic and Cenozoic Eras (250 million years ago to present)
  • Timeline 4: The Cenozoic Era (last 10 million years of the Cenozoic Era)

The forms have divisions of the geological timescale along the bottom, and a numerical timescale across the top.

Timescale_forms

Click here to download timeline forms.

So here you go, but you should probably know…

Plotting geological events on the forms can be tricky. Some events have well-known dates, but some don’t. Events may occur in a geological instant, or take hundreds of millions of years. I provided a sample timeline to give students an idea of what to do in different cases, and how to express uncertainty.

Sample_timeline

An example of how to plot events

Even with those considerations handled, the students who used this exercise were looking up dates for themselves, and that added another layer of complexity. I prepared a handout to guide them through some additional challenges.

Challenge 1: Different sources or different pages in the textbook give more than one date for an event.

Expect that this will happen. Sometimes a source will be general (akin to saying World War 2 happened in the twentieth century), and sometimes it will have more specific information (it began in 1939). Ideally, the interval on the timeline should reflect the most specific information available (i.e., the most specific date or the narrowest range of dates). This makes it much easier to see how the timing of one event compares to the timing of another. We could plot the appearance of both the Ford Model A and the Ford Mustang as single bars covering the twentieth century. But if someone who had never seen or heard of an automobile before looked at our timeline, they would lack the context to understand that some evolution had taken place.

Keep in mind that geologists themselves may not know the exact dates of a particular event. The boundaries of the timescale can also shift if new information comes to light, so an older source might put the same event at a slightly different time than a new one.

In the end, students shouldn’t get hung up on finding exact dates (because mostly they won’t be able to), but they should be trying to get the dates in the right ballpark, and trying to make that ballpark as small as possible.

Challenge 2: The textbook or other source mentions a geological time interval that isn’t at the bottom of the form.

The forms have increments of the geologic timescale (eras, periods, and epochs in some cases) at the bottom, but these intervals are in fact subdivided into smaller ones. For example, the Devonian period is divided into Early, Middle, and Late epochs. The Late Devonian is divided into the Frasnian and Famennian ages. To figure out where a division belongs, consult the Geological Society of America’s Geologic Time Scale.

Challenge 3: The source says an event happened in the “upper” or “lower” of some interval.

When talking about the timescale, periods are sometimes divided into Early, Middle, and Late. These are official designations for the timescale. In contrast, when talking about the rocks themselves, a layer may be referred to as “Upper Devonian.” “Upper” and “Lower” refer to the position of a bed in a stack of rock layers. Older beds are lower down, and younger beds are higher up. While careful decisions have been made about the ways in which uppers and lowers fit into the timescale, a rough approximation for this exercise would be to treat “Upper” the same  as “Late,” and “Lower” the same way as “Early.” A less-rough approximation would be to look up the ages of the units in question.

 

Ways to use the timelines

My students used the timelines to plot events listed in assignments. Some students printed the sheets and wrote directly on them. Some students added to the timelines using drawing software, or using the mark-up tools within Adobe Acrobat. But if you wanted to go all out, you could print the forms out in mega-huge format, post them on the classroom wall, and stick on images or text to mark events.

Or you could turn them into PowerPoint backgrounds and have students build presentations on top of them.

Or you could make them SUPER-mega-huge in drawing software, decorate them all up with whats and whens, then print a poster.

Whatever you do, send pictures!

Categories: Assessment, Challenges, Science and such, Teaching strategies | Tags: , , , , | Leave a comment

Time: The final frontier

Timefleet Academy logo: a winged hourglass made of ammonites

A logo begging for a t-shirt

Here it is: the final incarnation of my design project for Design and Development of Educational Technology– the Timefleet Academy. It’s a tool to assist undergraduate students of historical geology with remembering events in Earth history, and how those events fit into the Geological Time Scale. Much of their work consists of memorizing a long list of complicated happenings. While memorizing is not exactly at the top of Bloom’s Taxonomy (it’s exactly at the bottom, in fact), it is necessary. One could approach this task by reading the textbook over and over, and hoping something will stick, but I think there’s a better way.

I envision a tool with three key features:

  • A timeline that incorporates the Geological Time Scale, and “zooms” to show events that occur over widely varying timescales
  • The ability to add events from a pre-existing library onto a custom timeline
  • Assessments to help students focus their efforts effectively

Here’s an introduction to the problem, and a sketch of my solution. If your sensors start to detect something familiar about this enterprise then you’re as much of a nerd as I am.

Timefleet Academy is based on the constructionist idea that building is good for learning. Making a representation of something (in this case, Earth history) is a way of distilling its essential features. That means analyzing what those features are, how they are related, and expressing them explicitly. Ultimately this translates to the intuitive notion that it is best to approach a complex topic by breaking it into small digestible pieces.

Geological Time Scale

This is what you get to memorize.

As challenging as the Geological Time Scale is to memorize, it does lend itself to “chunking” because the Time Scale comes already subdivided. Even better, those subdivisions are designed to reflect meaningful stages (and therefore meaningful groupings of events) in Earth history.

There is an official convention regarding the colours in the Geological Time Scale (so no, it wasn’t my choice to put red, fuchsia, and salmon next to each other), and I’ve used it on the interface for two reasons. One is that it’s employed on diagrams and geological maps, so students might as well become familiar with it. The other is that students can take advantage of colour association as a memory tool.

Assessments

Assessments are a key difference between Timefleet Academy and other “zoomable” timelines that already exist. The assessments would come in two forms.

1. Self assessment checklists

These allow users to document their progress through the list of resources attached to individual events. This might seem like a trivial housekeeping matter, but mentally constructing a map of what resources have been used costs cognitive capital. Answering the question “Have I been here already?” has a non-zero cognitive load, and one that doesn’t move the user toward the goal of learning historical geology.

2. Drag-and-drop drills

The second kind of assessment involves drill-type exercises where users drag and drop objects representing events, geological time periods, and dates, to place them in the right order. The algorithm governing how drills are set would take into account the following:

  • The user’s previous errors: It would allow for more practice in those areas.
  • Changes in the user’s skill level: It would adjust by making tasks more or less challenging. For example, the difficulty level could be increased by going from arranging events in chronological order to arranging them chronologically and situating them in the correct spots on the Geological Time Scale. Difficulty could also be increased by placing time limits on the exercise, requiring that the user apply acquired knowledge rather than looking up the information.
  • The context of events: If drills tend to focus on the same group of events, the result could be overly contextualized knowledge. In other words, if the student were repeatedly drilled on the order of events A, B, and C separately from the order of events D, E, and F, and were then asked to put A, B, and E in the right order, there could be a problem.

The feedback from drills would consist of correct answers and errors being indicated at the end of each exercise, and a marker placed on the timeline to indicate where (when) errors have occurred. Students would earn points toward a promotion within Timefleet Academy for completing drills, and for correct answers.

Who wouldn’t want a cool new uniform?

How do you know if it works?

1. Did learning outcomes improve?

This could be tested by comparing the performance of a group of students who used the tool to that of a control group who didn’t. Performance measures could be results from a multiple choice exam. They could also be scores derived from an interview with each student, where he or she is asked questions to gauge not only how well events are recalled, but also whether he or she can explain the larger context of an event, including causal relationships. It would be interesting to compare exam and interview scores for students within each group to see how closely the results of a recall test track the results of a test focused on understanding.

For the group of students who have access to the tool, it would be important to have a measure of how they used it, and how often. For example, did they use it once and lose interest? Did they use it for organizing events but not do drills? Or did they work at it regularly, adding events and testing themselves throughout? Without this information, it would be difficult to know how to interpret differences (or a lack of differences) in performance between the two groups.

 2. Do they want to use it?

This is an important indicator of whether students perceive that the tool is helpful, but also of their experience interacting with it. Students could be surveyed about which parts of the tool were useful and which weren’t, and asked for feedback about what changes would make it better. (The option to print out parts of the timeline, maybe?) They could be asked specific questions about aspects of the interface, such as whether their drill results were displayed effectively, whether the controls were easy to use, etc. It might be useful to ask them if they would use the tool again, either in its current form, or if it were redesigned to take into account their feedback.

Timefleet in the bigger picture

Writing a test

All set to pass the test of time

Timefleet Academy is ostensibly a tool to aid in memorizing the details of Earth history, but it actually does something more than that. It introduces students to a systematic way of learning- by identifying key features within an ocean of details, organizing those features, and then testing their knowledge.

The point system rewards students for testing their knowledge regardless of whether they get all of the answers right. The message is twofold: testing one’s knowledge is valuable because it provides information about what to do next; and testing one’s knowledge counts as progress toward a goal even if you don’t get the right answers every time. Maybe it’s threefold: if you do enough tests, eventually you get a cape, and a shirt with stars on it.

Categories: Assessment, Learning strategies, Learning technologies | Tags: , , , , | 3 Comments

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