5.2.1Tools
Applying Technology to Collect Data in Biology — IB Biology SL Revision Notes & Topical Questions
5 min read 5 parts Lesson 5 of 10
Part 1 of 5Data Loggers and Sensors
Technology allows data to be collected faster, more often and with less human error.
Data logger
- An electronic device that records readings from sensors at set time intervals and stores them for later transfer to a computer.
pH sensor
- Monitors acidity of a solution, for example while studying how pH affects enzyme activity.
Temperature probe
- Records temperature changes continuously, such as during a respiration or enzyme investigation.
Light and oxygen sensors
- Light sensors measure light intensity and oxygen sensors follow gas concentration, useful in photosynthesis experiments.
Physiological sensors
- Heart-rate monitors and spirometers record human responses such as heart rate and breathing volume during exercise.
Part 2 of 5Other Digital Tools
Other Digital Tools
Digital cameras
- Time-lapse photography records slow changes such as germination, growth and cell division.
Digital microscopes
- Images can be saved, measured and compared with others, and shared among groups.
Remote devices
- Sensors left in the field collect data from sites that people cannot visit continuously,
- such as temperature at different depths of a lake.
Databases
- Large collections of data, such as genome sequences, can be searched and filtered quickly.
Part 3 of 5Using a Logger
1
Choose the sensor that matches the variable and check that its range suits the expected values.
2
Calibrate the sensor against a standard so that its readings are accurate.
3
Set the sampling interval and the total time, balancing the amount of data against the speed of change.
4
Start the logger and keep other variables controlled while it records.
5
Transfer the data to a computer and check them for faults before processing.
Part 4 of 5Advantages and Limitations
Frequent readings
- Many readings are taken in a short time, which reveals fast changes that people might miss.
Reduced human error
- Automatic recording avoids reaction-time errors and reading mistakes.
Continuous recording
- Logging can continue overnight or in dangerous places.
Limitations
- Sensors can be costly, need calibration and may be affected by battery life, drift or software faults.
| Method | Strength | Weakness |
|---|---|---|
| Manual stopwatch and thermometer | Cheap and simple | Reaction-time error, few readings |
| Logger with probe | Fast, precise, continuous | Cost and calibration |
Part 5 of 5Exam Checklist & Tips
5.2.1 – Key Points for the Exam
- Data logger A device that records measurements automatically over time.
- Sensor A device that detects a physical or chemical quantity and converts it to a signal.
- Sampling interval The time between successive readings.
- Calibration Checking an instrument against a standard to ensure accuracy.
Common Mistakes
- Assuming that data from a sensor are always accurate without calibration.
- Setting a sampling interval too long to capture a rapid change.
- Saying technology removes all errors; systematic errors remain if the sensor is faulty.
- Forgetting to control other variables while the logger runs.
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