Download Introduction to Data-logging - CMA

Technology Enhanced
Inquiry Based Science Education
Introduction to Data-logging
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Data-logging
Process of measuring and recording data over a
period of time via a data-logger and sensors. This
process is controlled by software running on a
computer or on a data-logger itself.
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Sensors
Sensors are
electrical devices
that measure
physical quantities
and convert them
into electrical (often
voltage) signals.
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Biology:
Many physical properties can
be measured with sensors.
Blood pressure, Gas CO2, Conductivity,
Dissolved O2, ECG, Heart rate, Light,
Gas O2, Relative humidity, Spirometer,
Temperature …
Chemistry:
Conductivity, ORP, pH, Pressure,
Salinity, Temperature, Turbidity,
Transparency, Voltage …
Physics:
Acceleration, Angle, Charge, Current,
Distance, Force, Light, Magnetic Field,
Pressure, Radiation, Sound,
Temperature, Voltage …
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Data-logger
A data-logger converts the electrical signal
generated by a sensor into a digital code, which
is processed by the device itself or sent to the
computer.
A data-logger connected to a computer
via USB port, data collection is controlled
by software running on the computer.
A portable data-logger, data collection
is controlled by software running on the
data-logger.
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Data-logger
Different data-loggers are available for different
school levels.
Primary
Middle/High (Calculators)
Middle (Lab)
High (Lab)
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Middle (Portable)
High (Portable)
Software
Dedicated software Coach running on the datalogger or on the computer which allows to:
• Monitor the measured data
• Control the process of data collection – how long and how
often to measure
• Collect data according
to the given settings
• Plot the collected data
• Display data in meters
and as digital values
• Analyze and process
the data
• Store the data.
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Biology
Recording ECG
• Using the ECG sensor to record and to study the
electrical activity of the heart.
• The heart produce electrical voltages that are
measured via electrodes placed on the skin of the
wrists.
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Biology
Measuring heart rate
• Using the heart rate sensor to measure heart rate.
• Each time that the heart contracts, blood is pumped into
the arteries. The Heart Rate sensor monitors the flow of
blood through the ear lobe, it shines a light through and
measures the light that is transmitted.
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Biology
Photosynthesis
• Investigating processes of
photosynthesis.
• Using the CO2 gas sensor to
monitor CO2 gas production by
green spinach leaves in dark
and in different lights.
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Biology
Photosynthesis
• Monitoring photosynthesis over
a longer period of time (72 h).
• Many sensors can be used for
such investigation: O2 gas, CO2
gas, light, temperature, humidity.
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Biology Respiration of maggots
• Monitoring the process of respiration by maggots.
• CO2 sensor is used to monitor the level of carbon
dioxide in a closed respiration chamber containing living
fly maggots.
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Chemistry Endothermic reactions
• Measuring temperature during endothermic and
exothermic reactions.
• During the spontaneous reaction between sodium
carbonate (Na2CO3.10 H2O) and citric acid
(C6H8O7.H2O) a temperature decrease occurs.
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Chemistry
Acid base titrations
• Measuring the pH value during acid-base titration.
As acid is added to the base, the pH gradually changes.
At the equivalence point the change is very rapid.
• Adding of the titrant can be done automatically by
controlling a step-motor burette. In this way the added
volume of the titrant can be accurately determined.
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Chemistry Temperature of flames
• Thermocouple sensor measures temperatures between
-200C and 1400C and is used to study temperature
inside flames.
• Temperature differences between several places in a
flame can be easily demonstrated.
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Chemistry
Rate of reaction
• Observing the rate of a chemical reaction and how
different factors influence the rate.
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Chemistry Energy content of food
• Determining energy content of a potato chip by
measuring the heat release from its combustion.
• Measurement with temperature sensor placed in good
thermal contact with the calorimeter. The heat can be
calculated by comparing to a calibration measurement
made with a standard electric lamp in the place of the
burning chip.
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Physics
Changing of state
• Measuring with a temperature sensor.
• Observing process of changing state, from liquid to
solid, during cooling of stearic acid.
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Physics
Sound waveforms
• Investigating the waveforms of sound waves and
sound beats.
• Very short (between 50 and 500 ms) and very fast
(50 000 Hz) measurements with the sound sensor
make sound visible.
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Physics Measuring speed of sound
• Determining the speed of sound in air using the echo
method.
• The sound sensor detects the initial sound and its
echo - sound reflected off the opposite end of the tube.
From the known distance and traveling time the speed
of sound can be calculated.
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Physics Electromagnetic induction
• Measuring the voltage induced by a magnet falling
through a coil.
• Investigating how the induced voltage is affected by
reversing a magnet or by using magnets of different
strengths.
• The measurement is started automatically by using
triggering.
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Physics
Boyle’s law
• Investigating the relationship between the volume
and the pressure of air in the syringe (Boyle’s law).
• The air pressure is measured with the pressure
sensor and the respective value of the air volume is
typed in via keyboard.
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Educational benefits of data-logging
• Data-logger becomes an universal instrument
Data-logger equipped with a selection of sensors
becomes an universal measurement instrument and
can be used in many different experiments.
• The measurement process is automatic
Data collection and the presentation of the data in
table and graph format are automated. This gives
extra time to focus on the physical phenomena and
different aspects of an experiment.
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Educational benefits of data-logging
• Remote logging - data may be collected and
stored independently of the computer
This allows the collection of data in a wide variety of
environments, including outdoors, and facilitates
collection over long periods of time, beyond the
normal scope of lessons in school.
• The rate of data collection is available over a wide
range of frequencies
Very fast and very slow rates of data collection provide
new contexts for gathering data and expand students'
experience of phenomena.
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Educational benefits of data-logging
• Real-time presenting data while being collected
This makes data collection an interactive process
whereby direct observations may be immediately
compared with the graph, encouraging thinking about
the data.
• The accuracy of measurements and recording
This is superior to manual traditional methods.
• The reduction of errors in taking readings
This results in better quality information which
potentially improves the clarity of relationships
between variables.
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Centre for Microcomputer Applications
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