Laboratory Based Case Studies

Frank J. Dinan

Dept. of Chemistry/Biochemistry

Canisius College

Cookbook-101

• Re-crystallization Experiment

• Set up a sand bath assembly as follows: Requisition a Thermowell heater, support plate and digital thermometer. Attach the support plate to a ring stand. Fill the cavity of the Thermowell heater with sand to within one centimeter of the top and set it on the support plate. Adjust the apparatus to a convenient height. Position the digital thermometer so that the tip of the probe almost touches (< 1 centimeter) the bottom center of the heating well (DO NOT USE A MERCURY THERMOMETER). Secure the thermometer to the ring stand with a one-hole rubber stopper and a three-pronged clamp. Connect the Thermowell heater to a (disconnected) Powermate heat controller, or its equivalent. After assuring that the Powermate control is in the OFF mode, connect it to an electrical outlet. Place it on a low setting (setting 2 for Model 3A). The sand at the bottom of the well should reach 100 deg. C within 20 minutes. If this does not occur, increase the dial setting by one unit and wait for 5 minutes for continued heating, then note the temperature. If the temperature has not yet reached 100 deg. C, repeat the process until the temperature remains a little (<5 deg.) above 100 deg.. The thermometer may then be removed. Record the Powermate setting in the indicated spot on page 2 of the data sheet provided for this experiment.

• Etc, etc.,etc..

A Teacher’s Tale

• Frustration with expository (cookbook) labs

• The “solution”

• The response

• Resignation

Strengths of Expository Labs

• Topic well defined

• Explicit instructions

• Goal known in advance

• Teaches technique

• Minimal investment in equipment, personnel

• Simultaneous instruction of large numbers

Weaknesses of Expository Labs

• “Cookbook” directions

• No creativity or HOTS

• Minimal learning

• No reflection, synthesis or analysis

• Reports forms to be “filled out”

Lab Based Case Studies Goals:

*Increased student involvement, responsibility.

*Student planning of work, evaluation of data, interpretation of results.

*“Real-world” reports.

Characteristics of Lab Based Cases

***A Good Hook***• Challenging problem, experimental solution• Minimal, but appropriate, faculty guidance

provided• Consideration of student safety • Requires “real-world”, narrative report• Examples follow

Avogadro Goes to Court(WSJ)

• Originally 2300 word case study

• Professor’s challenge to class

• Successfully student law suite

• Remission of tuition, damages

• Lab/class case--same challenge

Avogadro Goes to Court, But You Can Save Him

• Shortened (~2300 to ~350 words)• Briefly outlined• Challenged to save Avogadro• Students plan experimental approach• Equipment, material available on request • Experiments carried out, calculations done• Narrative report to law firm of Dewey Cheatem &

Howe

Analysis of a Murder Lab Case(NPR)

• Boy’s headless, limbless, nude torso floating in Thames

• Ritual sacrifice • Identification seemingly impossible• Professor’s research on Sr distribution• Bone Sr content indicated Nigerian origin• Analysis narrowed origin to 500 sq. mi. region • Clever detective work led to apprehension of

”persons of interest”

Analysis of a Murder Lab Case

• Students given summary of case• Act to “assist” Scotland Yard• Given victim’s “bone sample” for analysis• Given samples “from different regions of Nigeria”• Student experimental data indicates location of

victim’s Nigerian home• Students act as detectives, plan apprehension of killer• Report of case written to “Chief Inspector”• Published in Journal of Chem. Education, 2007

Two Versions of Murder Case

• Versions for advanced and intro. courses

• Advanced version: students analyze “bone samples” for their Sr concentration

• Intro. level version: students interpret Sr concentration data sets

• In both, data evaluated, conclusions drawn, plan formulated, report written

FDA Inspired Lab Case

• Juicing the juice complaint (FDA)

• Fresh vs. reconstituted orange juice

• Fluoride ion concentration key difference

• Fluoride ion selective electrode

• Students approach based on F ion concentration in two juice types.

A Metabolic Murder Mystery

A Metabolic Murder Mystery

Same Case, Two Labortory Experiments• Patricia Stallings murder accusation• Conviction, reversal, release, apology• Students placed in role of lab personnel• Results “determine guilt or innocence”• Must avoid errors of hospital laboratory• Gas chromatography, general chemistry• PCR, biochemistry laboratory

Why Narrative Reports?

• Lab reports often form(s)• Unlike “real-world” reports• Science students writing skills often inferior to

liberal arts students• Lack of practice, experience• Student’s skills improve sharply with practice,

instruction• Poor quality reports returned for re-writing.

Additional Lab Based Case Studies

• Accidental Drowning or Foul Play by Monica Konaklieva, American Univ.

• Filthy Lucre by Ed Acheson, Millen Univ.• Dem Bones: Forensic Reconstruction by Alease

Bruce, U. Of Mass. At Lowell• Shark Attack! by Herbert House, Elon University• The Zoom Lens: A Case study in Optics by Alan

Cheville, Oklahoma State University

Your Turn!

• Develop lab based case

• Good “hook”

• Student directions

• Learning goals

• Narrative report