Lab Design Tips

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Labs take much longer to prepare than lectures! But they are worth the work, if student learning and interest in science are our aims. To design a lab consider the following questions:

1. What is the sequence and role of the lab in the current lesson or unit?
   • Will this lab introduce students to phenomena from which concepts will be derived? Is it placed early in the unit plan?
   • Or does it follow the classroom presentation of concepts and serve to illustrate what students already "know"? Is it placed late in the unit plan?
   • Or is the primary goal of the lab to familiarize students with a technique or specific instrumentation?
2. Will the lab be an open-ended exploration?
   • Exemplifies scientific investigation as a problem-solving enterprise.
   • Problems are natural extensions of students' previous knowledge; drawing upon familiar concepts and investigative techniques.
   • May extend over several class periods.
   • Requires constant ongoing monitoring of student progress.
   • A great challenge is how to keep students from becoming overwhelmed, stranded, or discouraged.
   • May be extended into longer-term research projects or personalized instruction.
   • Examples: Microscopy, local water testing; animal behavior study; aquarium ecosystem management.
3. Or will the lab be highly structured and directed?
   • A carefully-sequenced, highly-structured lab is not necessarily a cookbook or recipe lab, if students are required to think critically and creatively.
   • Structure and direction are necessary if the materials are potentially dangerous or the desired conditions and observations quite complicated.
   • Identify all materials and equipment; provide a detailed procedure; specify observations to be made, data to be taken, or calculations to be performed.
   • More likely to be contained within a single period.
   • Structured labs may be appropriate early in a course, when introducing new instruments or experimental techniques, or when the required experimental conditions are elusive and unusual.
   • For an example, see the Lunar Phases lab.
4. Is the lab sequenced so as to stimulate the development of formal thinking? That is, does the lab begin with concrete experiences and then lead to formal reasoning rather than vice-versa?
   • Concrete: Are concepts initially defined operationally? Observations made which can be extrapolated? Intangible processes visually or kinesthetically modelled?
     • If the lab is synthetic, beginning with abstract concepts (such as the ideal gas law) and requiring application or transfer of formal concepts, were those concepts introduced in previous days with concrete demonstrations and modelling? Has there been a prior establishment of a knowledge base adequate for concrete thinkers?
   • Formal: Are concepts transfered to other applications later, upon introduction of formal definitions? Are predictions made through a chain of reasoning, rather than mere extrapolation?
   • Rather than "explaining unknown facts through inscrutable theories" (J. Dudley Herron) are students led to intelligible theorizing through the discovery of unexpected facts and the experience of significant phenomena?
5. Are students made aware of their own methodologies and reasoning strategies? Do they critically reflect on the experimental design? Recipe or hands-on activity without "minds-on" learning is meaningless and trivial. Concrete experiences become meaningful only when students think about what they are doing. Can students answer questions such as these:
   • What steps did you follow to do this experiment?
   • Would you explain that to me?
   • How would you explain this to someone who knew nothing about it?
   • Why did you do it that way?
   • Which variables are controlled? Which are not?
   • What is your evidence for that? Do we need more evidence?
   • Do the data surprise you?
   • To what degree are your results reliable? Why are you sure of that?
   • How might you get better data?
   • What experimental conditions contribute most to the uncertainty of your results? What are possible sources of experimental error?
   • Are there other ways of doing this? Are there other ways of thinking about this?
   • Should this be done again?
6. Do students know how they know, and recognize what they don't know? Are the grounds of inference and limits of knowledge understood?
7. Do students interact with one another and solve problems in a collaborative manner?
   • Student-student interactions make students more aware of their own reasoning strategies.
   • Formal thinkers will model reasoning skills for others. Sometimes students who have just discovered something are the best teachers.
   • Concrete thinkers will ask penetrating questions of those whose grasp of the matter is formal, challenging them to rethink, extend, or better articulate their ideas. We rarely understand something clearly until we have to explain it to someone else.
   • Oftentimes students are more at ease in asking questions of their peers rather than of the instructor, for fear of exposing their ignorance. No one wants to feel stupid.
8. Are lab phenomena and data quantified and analyzed mathematically?
9. What is the role of computer simulations or data analysis for this lab?
10. Do students need their own printed copies of the lab?
    • Do they need to study it beforehand?
    • If so, have you included a "pre-lab" assignment to turn in as a "ticket" to the lab?
    • If not, and if you have adequate time between lab sections, make copies for one lab section at a time. You will in all likelihood want to revise it for each subsequent lab section on the basis of creative misunderstandings and unsuspected ambiguities latent in the preliminary versions.
    • Will the students write up the lab in a notebook? Lab Notebook Tips.
11. "Students at all grade levels and in every domain of science should have the opportunity to use scientific inquiry and develop the ability to think and act in ways associated with inquiry, including asking questions, planning and conducting investigations, using appropriate tools and techniques to gather data, thinking critically and logically about relationships between evidence and explanations, constructing and analyzing alternative explanations, and communicating scientific arguments." National Science Education Standards, ch. 6, p. 105.
12. "Designing and conducting a scientific investigation requires introduction to the major concepts in the area being investigated, proper equipment, safety precautions, assistance with methodological problems, recommendations for use of technologies, clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other than the actual investigation. The investigation may also require student clarification of the question, method, controls, and variables; student organization and display of data; student revision of methods and explanations; and a public presentation of the results with a critical response from peers." National Science Education Standards, ch. 6, p. 175.

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