Experimenting from a distance: optical spectrometry via the Internet Lars-Jochen Thoms.
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Transcript of Experimenting from a distance: optical spectrometry via the Internet Lars-Jochen Thoms.
Experimenting from a distance:optical spectrometry via the Internet
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 2
Munich, Bavaria, Germany
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 3
physics
spectrometry
biophysics astrophysics
chemistry
eligible curriculum inBavarian higher education
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
remotely controlled laboratory (RCL)
# 4
user
server
webcam
outline
educational POV
physical POV technical POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 5
physical POV
light source spectrometeroptical fiber
350 450 550 650 750 850 9500
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wavelength in nm
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specifications• linear silicon CCD array• 650 enabled pixels• 350-1000 nm• 12 bit A/D resolution• 75 photons/count
@400nm• 25 µm entrance slit• ~2.0 nm FWHM
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
350 450 550 650 750 850 9500
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wavelength in nm
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# 6
physical POV
problems• especially advanced
learners identify the acquired spectrum asblack-body radiation
• Mind spectral sensitivity!
• knowledge about the measurement processcritical attitude
• no energy information given
• absolute irradiance measurement needed
350 400 450 500 550 600 650 700 750 800 850 900 950 10001
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spectral sensitivity
wavelength in nmmeg
ap
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lg
x 1000
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
obtain calibration data
# 7
radiometric calibration standardcalibrated tungsten halogen light source
fit sample spectrum toknown spectral power
distribution
calibrationfactor
in µJ/count per pixel
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 8
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from apparent to true spectrumsample [count]dark [count]sample-dark [count]absolute irradiance [µW/cm²/nm]
wavelength in nm
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ab
solu
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n µ
W/c
m²/
nm
spectralirradianc
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darkspectru
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acquired sample
calibration
factor A Δt Δλ: : :sample - dark
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
cosine-corrected probe
# 9
light source spectrometer
true spectral irradiance needs 180° field of view
optical fiber
diffusing material:opaline glass~180° FOV
© Ocean Optics, Inc
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
pusher.com
# 10
technical POV
client
WebSocket service (RESTful)• distribute spectral data• distribute control data• user information• authenticated users
web server
http service (PHP)• authentication• provide
website
RCL spectrometer serverwindows service (C#)• acquire spectrum• calculate irradiance• push data via
WebSocket• listen for control data• control experiment
IP cam
• capture video stream
spectral irradianc
e
acquired sample
HTML5 browser (JS)• display spectra• control experiment• ask for authentication• display webcam
control ?
special challenge:very high restrictionsin German schools!
no static ip needed!
DATABASEdatabase
assessment
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
control
# 11GIREP-MPTL 2014, Palermo, 08.07.2014Lars-Jochen Thoms, Raimund Girwidz
technical POV
light source
cosine-corrected probe
optical fiber
spectrometer• set acquisition
parameters• integration time• boxcar width• samples to average
• choose light source• tungsten lamps• tungsten halogen
lamps• compact fluorescent
lamps• light emitting diodes• light bulbs• reflector lamps
carousel
Experimenting from a distance:optical spectrometry via the Internet
control
# 12GIREP-MPTL 2014, Palermo, 08.07.2014Lars-Jochen Thoms, Raimund Girwidz
technical POV
light source
cosine-corrected probe
spectrometer
• set acquisition parameters• integration time• boxcar width• samples to average
• choose light source• tungsten lamps• tungsten halogen
lamps• compact fluorescent
lamps• light emitting diodes• light bulbs• reflector lamps
carousel
optical fiber
Experimenting from a distance:optical spectrometry via the Internet
control
# 13GIREP-MPTL 2014, Palermo, 08.07.2014Lars-Jochen Thoms, Raimund Girwidz
technical POV
• set acquisition parameters• integration time• boxcar width• samples to average
• choose light source• tungsten lamps• tungsten halogen
lamps• compact fluorescent
lamps• light emitting diodes• light bulbs• reflector lamps
• move probe• ca. 1.5 m x 1.0 m
Experimenting from a distance:optical spectrometry via the Internet
control
# 14
technical POV
• set acquisition parameters• integration time• boxcar width• samples to average
• choose light source• tungsten lamps• tungsten halogen
lamps• compact fluorescent
lamps• light emitting diodes• light bulbs• reflector lamps
• move probe• ca. 1.5 m x 1.0 m
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
control
# 15
technical POV
• set acquisition parameters• integration time• boxcar width• samples to average
• choose light source• tungsten lamps• tungsten halogen
lamps• compact fluorescent
lamps• light emitting diodes• light bulbs• reflector lamps
• move probe• ca. 1.5 m x 1.0 m
• rotate probe• - 90° to 90°• (360° possible)• automatic available
many different parameters
a lot of opportunities
authentic experimenting
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 16Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
predefined setups
Experimenting from a distance:optical spectrometry via the Internet
# 17
educational POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
context based anchored instruction
objectives:• compare and rate spectra from
different light sources
Experimenting from a distance:optical spectrometry via the Internet
# 18
objectives:• compare and rate spectra from
different light sources• assess color temperature and
color fault • compare with color sensitivity
of the human eye• distinguish between physical
and physiological quantities
educational POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 19
objectives:• analyze energy efficiency
educational POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 20
objectives:• measure -decrease of radiation
with growing distance
educational POV
Compact Fluorescent Lamps:differences can be noticed betweenthe light coming from the gas dischargeand light coming from the fluorescent layer
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 21
objectives:• examine, distinguish, classify,
and rate the directional characteristics of radiation from different light sources
educational POV
Schultz (2010)
from introductory school physicsto advanced university courses
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 22Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
Experimenting from a distance:optical spectrometry via the Internet
# 23
educational POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
multiple representations
augmented reality
Experimenting from a distance:optical spectrometry via the Internet
# 24
educational POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
augmented reality
multiple representations
feedback
free formula input
Experimenting from a distance:optical spectrometry via the Internet
# 25
educational POV
Workshop on Remote Experiments for HE, Milton Keynes, 17.04.2015
Lars-Jochen Thoms
augmented reality
multiple representations
feedback
scaffoldingcross-linking multiple representations
linking theory and practice
Experimenting from a distance:optical spectrometry via the Internet
Thank you for your attention!
Lars-Jochen Thoms
myrcl.org