Posts Tagged With: learning activity

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.


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.


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

The Mission (Geo)Impossible Scavenger Hunt

It was a Saturday morning like any other and my husband and I were enjoying a cup of coffee while he channel surfed to find a program related to disassembling and reassembling automobiles. He paused on a channel showing the movie Smokey and the Bandit, a classic film from 1977 about an epic beer run between Atlanta and Texarkana. “I wonder if I drove that road,” he said.

So we looked at Google Earth and found that there were two possible highways that Smokey and the Bandit could have used to move their beer. And then I saw it: the intervening space had a variety of superposed plunging folds. The seed for Mission (Geo)Impossible was planted the moment I began to wonder how I might lead students on a path to make that discovery for themselves. I don’t recall whether it was I or my husband who came up with the actual notion of torturing challenging students with a scavenger hunt for information, but it certainly appealed to my nefarious side.

What is it, exactly?

Download the handout here.

Mission (Geo)Impossible is a series of 19 quests that teams of students complete for extra credit. Why 19? I like prime numbers. 17 seemed to few, and 23 was too many. The first time around the optimal number of quests was one of many unconstrained variables. Why extra credit? Because when I make up the quests I honestly have no idea whether students will be able to do them. They are meant to be challenging problems, and are of a type that I’ve never seen as part of an assessment or activity. Students go into this knowing it will be difficult (I make sure they know), and do so by their own choice so I can feel a little less guilty about how hard they work.

Why on Earth would students want to do this?

The enticement for them to try Mission (Geo)Impossible is a substantial bonus on their final grade. If their team completes all 19 quests, 2.5% is added to their grade. That means a 60% becomes a 62.5%. If their team finishes first, they get another 2.5% for a total of 5%.

That might seem like a lot, and I wrestled with whether this was appropriate or not, but in the end I decided it was legitimate for three reasons. First, it is a term-long project and they work very hard on it. Second, to complete it they must learn a lot of geology and do synthesis tasks at a level that I would never ask of students in an introductory physical geology class under other circumstances. Finally, I’ve applied similar curves to final grades, and with serious misgivings. To my mind, this extra credit work is a heck of a lot more legitimate than bumping grades so the class average falls in the magical 60% to 65% range.

I also try to entice them by imbuing the whole undertaking with a spirit of playful competition. Students are competing with me- I tell them I designed the quests to mess with them (true), and challenge them to beat me. They are also competing with their classmates. There is a bit of secret agent role-playing, too. It is Mission (Geo)Impossible, after all. They “activate” their teams by emailing a team name and roster to Mission (Geo)Impossible Command Central, and there is a Quest Master who confirms their activation.

How does it work?

The mechanics of the scavenger hunt are designed to keep the level of work manageable for me, to keep my interactions with teams as fair as possible, and also to leave students to their own devices. Those devices turn out to be very good, and likely better than students realize themselves, which is a big reason why I like this activity.

To begin with, I post a pdf containing 19 quests on the course website. The procedure they follow is to email their quest solutions to Mission (Geo)Impossible Command Central, and the Quest Master responds with one of three words: “correct,” “incorrect,” or “proceed.” “Proceed” means some part of their answer is correct, or they are going in the right direction, but I don’t provide any information about what they’re doing right. That keeps me from having to worry about whether I’ve given one team more of a clue than another.

They can submit as many solutions as they like, and they have taken advantage of this in interesting ways. One team submitted “anagram” as their first attempt on a quest. They were trying to figure out what sort of puzzle they were solving. If they had gotten a “proceed” they’d know it was an anagram. The puzzle turned out to be a substitution cipher rather than an anagram, but it was a clever approach nonetheless.

So what do these puzzles look like?

The quests specify a target (a general thing to aim at), and deliverables (what students must submit). Then they give the clue.

Here’s an example of one quest that they solved relatively easily:


Solution: Earthquake, Lisbon, Portugal

The key to this quest is realizing that the minerals can be assigned a number using the Mohs hardness scale. In the order the minerals appear, those numbers are 1, 7, 5, and 5… or 1755, a year. Students could google “events in 1755,” they might actually know what happened, or they might have read the syllabus and found the sidebar I included about the earthquake in Lisbon, Portugal, that happened on 1 November, 1755.

Here is another one. It proved a bit more challenging for some students.

dancing men

Solution: Paricutin. It’s a cinder cone while the others are stratovolcanoes.

If you’re a fan of Sherlock Holmes, you’ll recognize this as the cipher from The Adventure of the Dancing Men. Solving the cipher gives the following rows of letters:





If you break up the rows differently, you can get this:





These are the names of volcanoes. It’s possible students will recall what I’ve said about those volcanoes in class, and immediately realize that the first three are stratovolcanoes, while the last is a cinder cone. On the other hand, the solution might involve looking up each volcano, listing the important characteristics, noticing that Parícutin is a cinder cone while the others are not, and verifying that stratovolcano versus cinder cone is an important distinction. The latter scenario requires a lot of work and ends in a very clear idea about the difference between a stratovolcano and a cinder cone.

Anything that can be googled will be googled

When designing these quests there were a few things I wanted to accomplish. One was that students from a variety of backgrounds and with a variety of interests would be a valuable part of the solution. In fact, I wanted them to realize something very specific: that their background and perspective, whether they considered themselves “science people” or not, was indeed valuable for figuring out a puzzle about science.

To make Mission (Geo)Impossible a meaningful exercise, it was important that students could not simply look up the answer somewhere. As far as possible, I tried to make the clues things that could not be put into a search engine, or something that could be searched, but would only give another clue to the problem. At first blush, this might sound next to impossible, but here’s an example of something unsearchable:


Detail of a painting at St. Peter’s College

This is a blurry photograph of a corner of a painting. It’s a painting that students walk by daily. The photo is of tree branches, but they aren’t necessarily recognizable as such. There is simply nothing about this that gives you a searchable string. Students would have to recognize the painting, and proceed from there. In this case the deliverable was the age of bedrock beneath the College. Students had to realize that the painting was giving them a location, and then look at a geologic map.

Here are a few other things I kept in mind:

No extraneous information

I didn’t include things that weren’t relevant to the quest. At least not on purpose. The quests were hard enough, and there wasn’t anything to be accomplished by sending students on a false path. They did that on their own often enough.

No process of elimination

I wouldn’t give them a quest in the style of multiple choice because they could simply keep guessing until they got the right answer. Where quests had a finite number of options, there was either work involved to get those options (like the dancing men quest), or work involved in explaining a choice (ditto the dancing men).

Don’t restrict the quests to things explicitly addressed in class.

There is value in extrapolating knowledge and building on it. For example, in the case of Smokey and the Bandit, the plunging folds are easy enough to pick out with some searching, if you know what you’re looking for. However, the plunging folds I show in class are of the “textbook” variety. The ones between Atlanta and Texarkana are much more complex, but still discoverable if students think carefully about how plunging folds are expressed at Earth’s surface. In the end, they found the folds.

Use a wide variety of clues and puzzle types

As best I could, I used clues that involved a wide range of topics (literature, art, science, popular culture of the 1970s). I used puzzles that would appeal to different ways of thinking. Some involved interpreting images to get a word or phrase. For example, a pile of soil next to an apple core would be interpreted as “earth” and “core.” Some were ciphers, and some involved recognizing objects. Some were narratives, like the one below. Students used the stories to get the differences in timing between P-wave and S-wave arrivals, then used triangulation to find the location of an earthquake. But they had to find a map of Middle Earth first, and do some km to miles conversions.


It was an earthquake in Fangorn Forest.


So how did this go over with the victims students?

My class was never more than 23 students, and the uptake was 2-3 active teams each time. I would need surveillance throughout the College to see exactly how they responded to the quests (and I’m not sure I’d like what I’d hear). But from conversations with students it seemed there was the right amount of frustration to make solving the quests feel like an accomplishment. In all but one case, teams that started Mission (Geo)Impossible also finished it, or else ran out of time trying.


They submitted solutions at 5:30 in the morning, 11:00 in the evening, and sometimes during the lecture. They brought their quests to the lecture in case I dropped a hint. They came to visit me and said things like, “This is driving me crazy,” and “Why, Karla? Why?” I successfully (I think) suppressed a diabolical grin on most occasions. In fact, they put so much work into this that I felt bad about it from time to time. But it was an optional activity, I rationalized.

Wiggle room

When I started this I had no idea whatsoever whether students would be successful, but I did intend to supply a safety net if it was needed, and make sure their work was rewarded. This is my policy with everything I try in my courses.

In the first iteration things bogged down part way through the term, so to get students going again, I gave them an option: they could request one additional clue to a quest of their choice, or they could request clues for three quests, but I would pick which ones, and I wouldn’t tell them which I chose. (Heh heh.)

Naturally, the teams negotiated an arrangement whereby they sorted out which combination of options would work out to their collective advantage, and then they shared the information. At that point I was very glad I insisted on teams rather than letting individuals play, because as individuals they could conceivably ask for enough clues to specific quests to beat the system.


In the second iteration, I tried a new style of puzzles that turned out to be more difficult than I intended. By the end of the term, and after a massive effort, the teams were only about half way through. In that case I awarded the team with the most quests the 5% and 2.5% to the other team.


The third iteration

I will do this again, but with fewer puzzles (13- still a prime number), and with fewer difficult quests than last time. I will also give students some examples of quests from previous iterations. I’m hoping that will convince more students to get involved.

I won’t relax the rule about participating in teams. I tried that the second time around, and the individual participants either did not get started, or got hopelessly off on the wrong track. I do need to find a solution for students who want to participate, but aren’t comfortable approaching other students in the class who they don’t know.

But I will find a way to get as many students involved as possible, because the potential for this activity to give students confidence in their ability to approach difficult tasks- even seemingly impossible ones- is just too important.

Oh yes, and by the way…

I dare you.


Deliverable: x + y + z

Categories: Challenges, Learning technologies, Teaching strategies | Tags: , , , , , | 2 Comments

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