Transcript Use of a computer controlled spectrophotometer in home

Use of a computer controlled
spectrophotometer in home
chemistry experiments
Lawton Shaw and Robert Carmichael
Centre for Science, Athabasca University
Athabasca University
• 38,000 students
(7,900 FLE)
• Open registration
• Average age: 29
• 83% work while
they study
• Students from
across Canada and
abroad
Home Labs at AU
• General Chemistry I (>500 students per year)
• Home lab kit ships anywhere within Canada
Criteria for Home Lab Experiments
Practical:
• Need durable equipment
• Low cost
• Small size/weight
• Reliable experiments
• Safety & low chemical
toxicity
• “Green”
Lab Curriculum:
• Meaningful experiments
• Quantitative
measurements where
possible (e.g. mass,
volume, etc…)
• Introduction to
instrumentation?
Home Experiments
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Candle (observational)
Mass, volume
Spectrophotometry
Acid/base titrations
Gas constant
Colligative properties
Reaction Enthalpy
Qualitative cation determination
Quantitative analysis of P
Reaction stoichiometry (iodate, iodide)
Home-made colorimeter
D. Kennepohl and M. Connors ‘An Inexpensive Mini-colorimeter for Undergraduate Science Laboratories
, Australian Journal of Education in Chemistry, 2010, 70, 38-41
Vernier SpectroVis Plus
• CCD array
• 380-950 nm, 2.5 nm
resolution
• 1 s spectral acquisition
• Powered with USB
connection
• PC controlled
• Downloadable software
(free)
• < $500
Experiment: Determining %ASA in
an aspirin tablet
Student Data – Spectrum of Fe(III)
salicylate complex
Student Calibration Data
SpectroVis Plus
• Approx. 250 shipped to date
• No damage to instruments
(so far!)
• Much positive feedback from
students and tutors
• Students satisfied with good
data quality
Problems/Criticisms
• Students may have difficulty installing
software (infrequent and always resolved)
• Software does too much of the work for
students (i.e. black box type calculations)
New learning experiences for
students
• Computer control of an instrument (e.g.
setting parameters)
• Instrument calibration
• Electronic capture of data
• Electronic data processing
What we’re working on…
• Preparing to survey students on their
previous experience with instrumentation,
and how they rate their learning
experience
• New home lab experiments with the
SpectroVis
Acknowledgments
• Chemistry 217 tutors (Jim Robinson,
Nyron Jaleel, Klaus Thomson, Kate
Stuttaford)
• Lab Kit Manager, Neil Sexton
• Knowledge Infrastructure Program
• Athabasca University