DIDACTICALLY CORRECT SENSORS FOR DIGITAL LABS Denis Zhilin, Moscow Institute for Open Education,...
11
DIDACTICALLY CORRECT SENSORS FOR DIGITAL LABS Denis Zhilin, Moscow Institute for Open Education, School #192, [email protected] Oleg Povalyaev, Scientific Entertainment Co, Moscow [email protected]
-
Upload
juliet-lee -
Category
Documents
-
view
221 -
download
3
Transcript of DIDACTICALLY CORRECT SENSORS FOR DIGITAL LABS Denis Zhilin, Moscow Institute for Open Education,...
DIDACTICALLY CORRECT SENSORS FOR
DIGITAL LABS
Denis Zhilin,Moscow Institute for Open Education,School #192,
Oleg Povalyaev,Scientific Entertainment Co, Moscow
THE DIGITAL LABSA system allowing to measure different
analogous parameters, put them into digital form, store, visualize and process
THE BENEFITSComputer takes routine procedures
reducing cognitive overloadFast measurements can follow quick
processesVisualizing parameters that humans do not
feel (pH)
THE PROBLEMThe choice of
sensors: rather available
than didactically necessary
• temperature• pH• conductivity• redox-potential• p(I)• optical density• gas pressure• dissolved O2
REPLACE SENSOROR CHANGE CURRICULUM?
Gas pressure sensor is used to develop the concept of stoichiometry,
butn = pV/(RT)
the change of pressure depends on
volume that can be very different
connection between gas amount and gas pressure causes cognitive overload
Volume is proportional to gas amount
(always p 1 atm, T 290K)
No cognitive overload
SOLUTION: GAS VOLUME SENSOR
HOW TO SEE WHAT IS HAPPENING?
Colorimeters with 3 mL cuvettes:
The cuvettes are concealed
No links between It’s impossible toobservations and add something tofigures the cuvette
No sense of Limitations forparameters forms experimental
design
SOLUTION: GATE SENSOR+ one can see
everything+ one can add
reactantsProblems with
adjusting?No! The side light
is taking into account
Another possible solution:immerse probe with optical fiber and mirror
HOW TO OPERATE?Drop counters for titration: - Requires adjustment- Requires calibration for each titrant- Can’t add large volumes of titrant
Too much time for struggling with the
sensor cognitive overload
No waiting time between adding a drop and fixing parameter value
Inaccurate results
SOLUTION: SYRIGNE SENSOR
Titrant could be added at any rate
Requires calibration only when the syringe type is changed
One can wait after adding drops to let the drop distribute in the system
COMPLICATED APPARATUS
pH-metric + colorimetric titration(Ex: checking the applicability of indicators)
THANK YOU FOR YOUR ATTENTION
Denis Zhilin,Moscow Institute for Open Education,School #192,
