Tag: scientific process

12 Cups: Thermal Energy

Students study the twelve different containers, using reason to deduce their thermal properties.
Students study the twelve different containers, using reason to deduce their thermal properties.

I gave the middle-schoolers twelve containers — cups, bottles, mugs, etc. — that I found around the classroom and asked them to figure out which one would keep in heat the best. In fact, I actually asked them to rank the containers because we’d just talked and read about thermal energy. This project is intended to have them learn about thermal energy and heat transfer, while discovering the advantages of the scientific method through practice.

Day 1: Observation and Deduction: When I asked them to rank that containers based on what they knew, I’d hoped that they’d discuss the thermal properties of the cups and bottles. And they did this to a certain degree, however, part of their reasoning for the numbers one and two containers, were that these were the ones I used. Indeed, since I use the double walled glass mug with the lid (container number 7) almost every day, while I only use the steel thermos-mug (container number 6) on field trips (see here for example), they reasoned that the glass mug must have better thermal properties.

The twelve containers are labeled with sticky notes, while students' initial assessment of thermal ranking is written on the paper pieces in front of the containers.
The twelve containers are labeled with sticky notes, while students’ initial assessment of thermal ranking is written on the paper pieces in front of the containers.

Day 2: Exploratory Science and Project Organization: On day 2, I asked the class to see how good their ranking of the containers was by actually testing them. Ever since the complex machines project where they had to choose their own objective, they’ve been wanting more independence, so I told them to pretend I was not in the room. I was not going to say or do anything to help, except provide them with a hot plate and a boiling kettle, and keep an eye out for safety.

They got to work quickly. Or at least some of them did while the other half of the class wondered around the room having their own, no-doubt important, conversations. I pulled them all back in after about half and hour to talk about what had happened. But before we discussed anything, I had them write down — pop quiz style — what their procedure was and how it could be improved. The vagueness of some of the answers made it obvious to both to me and the ones who had not been paying attention who’d actually been working on the project.

Experiments in progress.
Experiments in progress.

Of the ones who’d been working in the project, I brought to their attention that they’d not really spent any time planning and trying out a procedure, but they’d just jumped right in, with everyone following the instructions of the one student who they usually look to for leadership. Their procedure, while sound in theory would have benefited from a few small changes — which they did recognize themselves — and the involvement of more of the class. In particular, they were trying to check the temperature of the water every 10 seconds, but it would take a few seconds to unscrew lids, and about 5 additional seconds for the thermometer to equilibrate. They also were restricted because they were all sharing one stopwatch while trying to use multiple thermometers.

Day 3: First Iteration: Now that they’ve had a bit of trial by fire, tomorrow they’ll try their testing again. I’m optimistic that they’ve learned a lot from the second day’s experience, but we’ll see how it turns out.

On Rabbit Digestion

Figure 1. Undigested fiber from rabbit fecal pellets.

One of my favorite things is when my students teach me something I didn’t know. One of those things is that rabbits eat their own poop.

Well not exactly. According to Dana Krempels, from the University of Miami, rabbit fecal pellets (poop) are different from the other type of droppings that lagomorphs actually eat, which are called cecotropes (Kempels, 2010; Rabbits: The Mystery of Poop). Cecotropes apparently have lots of helpful bacteria and nutrients. Rabbits that don’t get to eat them tend to suffer from malnutrition.

Figure 2. Rabbit fecal pellets, with one mostly dissected, in a standard petri dish.

Independent Research Project

For her Independent Research Project (IRP) this term, one of my students researched rabbits, and, as was required, tried to find them on our nature trail. She found indirect evidence. Small fecal pellets in the grassy area next to the trail’s exit, just where her research said they might be (which was quite nice). The pellets were brought inside, dissected, and examined under the microscope (see Figures 1 and 2).

The magnified image showed what appeared to be a partially masticated (chewed) piece of fiber, probably grass. This is where I was informed about the double eating called cecotrophy. My student hypothesized that this sample might be something that had not been fully digested and the rabbit would come back and eat it another time.

The Scientific Process

I really like the scientific process that went into this project, even though I’m not sure I agree with the final hypothesis. The project started with background research that yielded a plan for field observation. The field observation resulted in samples being collected and returned to the lab for analysis. The analysis produced some interesting, enigmatic results, which lead to a proposed hypothesis that integrated the observations based on the original background research.

The only things I would like to add to this type of IRP is to have students include a detailed scientific sketch, much like the sketches of the early botanists and naturalists. I really like how these drawings integrate acute observation and artistic interpretation.

Oven calibration

Initial oven calibration curves (2009).

Catastrophic failure of one of our ovens! Last year when we started up the bread business, we bought two counter-top ovens within a couple of weeks of each other. They needed to be extra-large to fit two loaves of bread each, which made them a little hard to find. We got a EuroPro oven first, and when we found that it worked pretty well, we went back to try to get another. But just a week later, the store was out of stock and that type of oven could not be found in the city of Memphis or its environs.

Instead we got a GE model. The price was about the same, as was the capacity. We quickly realized that the GE was quite the inferior product. The temperature in the oven was never the same as what was set on the dial. Our bread supervisor at the time ran a calibration experiment, the results of which you can see above, so we still managed to use the oven. Only this year, three weeks into the term, it conked out.

We sold at least one underdone loaf before we realized what had happened, and received a detailed letter in response (which our current bread supervisor handled wonderfully in his own well worded letter). Fortunately, we have found a newer version of our EuroPro oven, which seems to work quite well.

I like the oven calibration exercise. It was a nice application of the scientific process to solve an actual problem we had with the business. Though I know it’s not quite the same, I like the idea of doing annual oven calibrations just to check the health of our equipment and help students realize that the scientific process is a powerful way of looking at the world, not just something you do in science.

Learning science

al-Hassan Ibn al-Haytham (b. 965-1039) (Image from Wikipedia)

Science is, at its core, hypothesis testing. To learn science learn the scientific method: figure out the precise question to solve (as best you can); come up with an answer you think might work (hypothesis); test it; and repeat as necessary while modifying the hypothesis. Almost all science experiments for middle school through college involve following a set of instructions in the lab manual. Only in independent research projects do students actually go through the scientific process and then it’s difficult because they don’t have the experience.

Part of the problem is that it takes time. Time to muddle through the though process of trying to figure out what exactly is a tractable question to solve. Time to come up to with a reasonable, testable hypothesis. Time to figure out how to test it. Time for iterating through the process again, although, once you’ve set up your experiment the first time doing it again and again is not that hard or time-consuming.

With our Montessori Middle School’s six-week cycle of work, and even with the two weeks dedicated to the Natural World, students should be possible to get through this process for at least one problem. They would probably have to dedicate the two weeks to a single problem/experiment and it would probably be terribly slow in the beginning.

To discover the truth about nature, Ibn a-Haitham reasoned, one had to eliminate human opinion and allow the universe to speak for itself through physical experiments. “The seeker after truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them,” the first scientist wrote, “but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration.” – Steffens (2008) (Ibn Al-Haytham: First Scientist)