Thursday, January 2, 2014

Hands On Experimentation as a Teaching Tool

The real world is hardly cut and dried, it is full of uncertainties, probabilities, and hypotheses to be verified. Introducing this into a classroom though, is hardly straightforward. Even adults are sometimes unprepared to deal with uncertainty. And young children are even less well equipped to handle uncertainty.

The Common Core State Standards introduce Statistics & Probability in grade 6, and the Next Generation Science Standards introduce the concept of measurement error and multiple measurements at about the same time.

Laboratory experiments provide a strong example of measurement error and probability and their interaction with other subjects. Laboratory experiments can be introduced just after probability and measurement error.

Hands on work, laboratory work, practical work, it has many names. It has even more benefits. Perhaps so many benefits that it is sometimes difficult to prioritize them for a given situation1,2. Further many of these benefits are distinct from standard classroom instruction and as a result at times "outcome measures consisted almost exclusively of paper and pencil achievement tests that were often poorly linked to the laboratory activities."

Not only do we need to be careful in constructing the laboratory component of our instructional content, we have to be careful how we access its effectiveness. Designing each of these requires a familiarity with scientific experimentation and the scientific method.

We have talked about the contextual sensitivity of knowledge, and the value of presenting the same material from multiple viewpoints over time. The laboratory experiment exercises both of these principles.

The first hand exposure to scientific principles provides a new path to insight on classroom material. At least as importantly, it necessitates dealing with real world issues such as what it means to validate or invalidate a hypothesis, dealing with experimental data, presenting experimental results, and drawing conclusions from experimental results. Entire books have been written on these topics 5,6.

Perhaps the most important of these, and one of the most difficult to grasp, is the need for experimental verification of reality. This concept lies at the heart of the scientific method, a deep understanding of which generates much more confidence in science and helps in the ability to differentiate legitimate from illegitimate claims both inside and outside of science.

An effective lab will be designed to illustrate and explore concepts from the other components of the coursework, better still if they also relate to the broader curriculum.

How do we introduce lab work to students? Start early. This example introduces laboratory work to 7th graders. While it is highly, and perhaps overly, procedural, it does introduce lab work. For example, I would not check the student data as soon as it was gathered, I would allow the students to continue on to the analysis and conclusion, and stress the questions of whether or not the conclusion is what they expected, and is the conclusion consistent with established science. Then follow up with the question of why, or why didn't, they expect the result. While this first example may serve as an introduction to more advanced lab work, it should be clearly understood as such an introduction by both the students and teachers. Can you see additional ways that this lab could be improved?

To many students, a laboratory activity has meant manipulating equipment but not manipulating ideas. Multiple studies confirm that the frequently observed ritualistic, even 'mindless' student behaviors observed in many laboratory activities stifle students' personal engagement in decision-making in the laboratory. These kinds of activities rarely uncover students' underlying beliefs; they do not encourage students to wrestle with their prior knowledge in making sense of their experiences, and they do not encourage them to reflect on their own thinking.3

Contrast the first example with another lab where once again middle school students tackle experimental work, but this time in an almost completely unstructured format. Here the students are confronted with a real world situation, their fish are dying due to a high pH, which would spike after a few days. When the teachers who had setup they system failed to find a cause, they involved their students in investigating the mystery. The students now know this is a real world investigation. According to the article, the students reached out to experts from UW-Milwaukee, who visited the school and worked with the students. This added more realism and helped the students follow accepted scientific methodology.

'With science, it's got to be hands-on, it's got to be real world,' said Stewart [one of the teachers]. 'Students did their own research for this, there's a sense of ownership for them.'

The real world nature of this lab will be hard to duplicate, but the successful involvement of eighth graders is promising and inspiring. Involving outside experts lends additional realism. Interestingly, the local cable company, Time Warner, has a program to connect practitioners with educational programs. Perhaps because it is new, there do not seem to be many programs visible in my geographic area.

Most students are best served by a path that touches on elements from both of these examples. For example provide a clear stage and goals for the lab as in the first example, while drawing the real world relevance and involvement of the students in designing the actual actions and analysis from the second.

The importance of hands on experience and dealing with errors and uncertainty in raw data speaks loudly to the superiority of actual experimentation over simulations of experimentations. Simulations can provide reinforcement of classroom material, and have a place in our instructional repertoire. However, they can not provide the confidence in science and the scientific method that flows from hands on experiments and direct observation. Fundamentally, simulations behave the way they do because that's how we built them. They are at least a layer or two of abstraction removed from actual physical reality.

  • Learning in and from Science Laboratories: Enhancing Students' Meta-Cognition and Argumentation Skills. Avi Hofstein, Mira Kipnis, Per Kind, in Science Education Issues and Developments. 2008, Nova Science Publishers, Inc.
  • The Role of Laboratory Work in School Science: Educators' and Students' Perspectives. Dr. Ali Khalfan Al-Naqbi, Dr. Hassan H. Tairab, Journal of Faculty of Education UAEU. Year 18, Issue No. 22, 2005.
  • Learning and Teaching in the School Science Laboratory: An Analysis of Research, Theory, and Practice. Vincent N. Lunetta, Avi Hofstein, Michael P. Clough, Handbook of Research on Science Education, 2007, Lawrence Erlbaum Associates, Inc.
  • The Role of the Laboratory in Science Teaching: Neglected Aspects of Research, Avi Hofstein, Vincent N. Lunetta, Review of Educational Research, Summer, 1982, Vol. 52, No. 2, Pp 201-217.
  • Statistical Treatment of Experimental Data, Hugh D. Young, 1962, McGraw-Hill Book Company, Inc. Company.
  • Beautiful Evidence, Edward R. Tufte, 2006, Graphics Pr.