This lesson details the data collection process for the Ecocolumn project detailed in the first two parts of this lesson sequence (see the links below).
On the first day of class after we’ve completed the construction of the ecocolumn, I devote an entire lesson to data collection and walk students through the data collection process described here.
Although the specifics may differ somewhat due to decisions made by your class during the design phase of the project, I include here some basic guidelines to manage an ongoing project.
Please note that this lesson actually describes the ongoing aspects of the project that will run for several weeks (in the case of my class, we ran from early October to early December, just a week before finals). Because of this fact, the instructional times for this lesson are all set at 0 minutes. Please realize this will take longer than 0 minutes.
Connection to Standard
In this lesson, students will write informative texts regarding scientific procedures, use technology to publish and update their work, use feedback from their teacher and peers to revise their work, and write routinely over an extended time frame.
Data collection overview
The ongoing data collection phase of the project gives students opportunities to develop skills at collecting and recording various kinds of data from their ecocolumns. Data collection will require students to use microscopes, computer software (we used Google Slides), rulers, pipettes, etc, and like anything that is skill based, it will take a lot longer for students to complete this work at the outset of the project. As they become more accustomed to the requirements of the data collection procedures, it will become possible to make the data collection be part of a routine that takes up a small amount of time on certain class days rather than a standalone lesson that would take up an entire class period.
My basic requirement for data collection is that students add both quantitative and qualitative observations of their ecocolumns on two separate days per week (my class usually meets 3 times a week). Additionally, students are required to add a minimum of 3 photos per week, including:
I have students keep a record of their data collection by making Google Slides. What wound up working best is that students made a separate slide for each day that they recorded observations. As you can see in this example of a group's data journal, this provides an organized platform for data collection. Additionally, having students continually "turning in" their work on this large project allows the teacher to offer comments in a timely fashion that will help students improve their data collection practices as the project progresses.
It does take some time to set up the Google Slides for each group, especially if none of the students in a particular group have used Google Docs in the past. In my case, almost every group had at least one member that already had a Google Docs account and group members that didn't have compatible email accounts were able to be added later in the project. In this way, most groups can begin actually recording their data online on the first day. If this severely cramps the lesson flow on the first data collection day, use your discretion and perhaps have them record their observations on paper.
Although I do make the first day of data collection it's own entire lesson, for the remainder of the project, I set aside about 20 minutes at the beginning of each class time for data collection.
Some other considerations
If your students decide that they will be following a strict, regular schedule when it comes to maintaining their chambers and collecting data, you may need to look at your calendar in advance to anticipate any days where students will need to either come in to water the plants or make some alternate plan to deal with a holiday or other schedule disruption.
Students should also check in with at least one other group to check their progress against others (while this is important to help them interpret and understand the observations they're making in their own ecocolumns, it also has the practical benefit of giving them comparative examples to improve their own data collection practices).
Please note that the data collection described here assumes you have access to at least one microscope per group. If you have fewer microscopes, you might rotate their use, but this will significantly increase the amount of time it takes for the whole class to gather data about the microorganisms in the aquatic chamber. If you have not previously worked with microscopes with your class, I suggest prefacing this lesson with the skill builder lesson on how to use a microscope.
If you don’t have microscopes, the project can still be carried out by simply observing qualitative characteristics of the aquatic chamber such as clarity, color, composition, etc. Another option would be to take a somewhat larger sample of water (an entire pipette would be 3mL) and transfer it to a small petri dish to be examined with a magnifying glass. If your students included silt or sand from a pond in their aquatic chamber, there’s a good chance that there will be tiny macroscopic invertebrates such as planaria, crustaceans, and assorted larvae. Even with a microscope, this secondary observation of larger organisms might be an interesting practice.
When students are observing the water sample, they should make general qualitative statements about the appearance of the water, but the real meat of the observation comes in studying the species present.
Two things are important to consider here, the diversity of species and the populations.
In regards to diversity, I ask students to write a detailed description of all the organisms they encounter and include a sketch of the organism. Once a particular species is described, they can assign it a nickname (more formal identification can follow if you want to devote time to that goal), in this way they can refer to the species in the future when other members are encountered, use it as a point of comparison (e.g., it’s like the “the squiggle monster” only bigger), and help them to manage the potentially rich species diversity. I recommend that the whole class used the nickname of the organism chosen by whichever group describes it first. Again, formal identification can follow: for identification purposes, I suggest the Guide to Microlife by Kenneth Rainis and Bruce Russell.
If you have access to a microscopic camera, this process is much easier as students can compare actual photos rather than their sketches, which makes identifying similar species in different bottles easier to accomplish. Another option, should students have the patience to line it up just right, is for them to use a cell phone camera and take a picture through the microscope. This picture shows how one of my students accomplished this somewhat difficult feat.
How to count the organisms? A hemacytometer is ideal, but a gridded slide will work. I’m not terribly concerned that they make estimates about the entire population, just that they are following the same procedures to count the organisms. Tutorials abound on youtube to use a hemacytometer, but I simply have my students use small gridded slides (with 1mm squares) and count the number of total organisms in the four squares at each corner of the slide. Then they average their total count by dividing the total number of organisms by four, giving an estimated population density per square millimeter (if my students are measuring total population size, they can multiply this by 100 as our slides have a gridded space of 1 square cm).
Depending on the way the project progresses, students may want to also count populations of individual species rather than the entire population. If not counting by species, dividing them by producers/consumers may be a good way for them to gather additional data about the makeup of their aquatic chamber.
Generally speaking, gathering data from the terrestrial chamber is simpler than from the aquatic chamber. In the earliest days, they aren’t likely to observe much, but perhaps a few sprouts will have broken the surface of the soil. I ask them to keep a top down diagram of the terrestrial chamber to show where plants are growing to get a sense of their distribution. Later on in the project, this may not be necessary as the plants get larger. It is helpful if they make some mark on the bottle to indicate the “front” so they can reorient the chamber the same way when observing it on different days. I encourage students to give a name to each plant, it’s a great way to keep track of each plant as a separate entity and it helps students invest themselves in the work of describing it, but mostly it’s just more fun.
Most of the data collected in this chamber is qualitative, describing the shape, color, and general appearance of the plants. In addition to describing the plants, I also encourage them to observe the soil itself, both from the top down view and the cross section afforded by the clear plastic bottle. Unlike the microorganisms in the aquatic chamber, it’s easy enough for students to photograph the plants, so I encourage them to take a daily picture of an “aerial” view and profile every day. It’s also helpful to take a picture of the entire ecocolumn once a day to show the aquatic chamber as well. Students should also sketch or photograph individual features of the plants such as leaves over time.
As far as quantitative data, I would ask students to mark on the “aerial” view diagram where the plants are situated relative to the walls of the chamber and include those measurements. As far as the plants themselves, I encourage the students to measure
If students are diligent about photographing this chamber and the entire ecocolumn, it can make for an interesting slideshow at the conclusion of the project. As I said above, I recommend students upload their pictures to their group's Google Slides so that they all have access to the photos and they are easily organized chronologically.
One week before the end of the project, I distribute the Project Debrief Worksheet to all groups so that they may begin working on the questions. At this time, I relax the requirement to continue gathering data, and allow them to instead focus on reflecting on what they learned during the project.
On the final day of the project (which comes two days before the final exam), I ask students to disassemble their ecocolumns and make any final observations should they feel they obtained any new, relevant information.
I ask students to complete their debriefs by the week before finals week to give me enough time to evaluate their whole project, but since I keep a weekly tally of each group's meeting or not meeting the requirement to make two posts (including 3 pictures) per week, all that remains for me to do at the end of the project is read and assess their debriefs. An exemplary student reflection is included here.