5.2.1Tools
Applying Technology to Collect Data in Biology — IB Biology HL Revision Notes & Topical Questions
5 min read 5 parts Lesson 5 of 10
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 5Sensors and Data Loggers
Sensors
- Sensors Input devices that detect a change, for example in temperature, light, pH, oxygen, carbon dioxide or heart rate,
- and turn it into an electrical signal.
Data logger
- Data logger A device that records the signals from sensors at set time intervals and stores the readings or sends them to a computer.
Continuous monitoring
- Continuous monitoring Readings can be taken for hours or days, even when no one is present, such as night-time respiration in a pond.
Sampling interval
- Sampling interval The time between readings must be short enough to show rapid changes but long enough to avoid too much data.
Section 2 of 5Digital Imaging and Remote Collection
Digital Imaging and Remote Collection
Digital microscope
- Digital microscope A camera on a microscope records images that can be measured and shared, which helps when counting cells or measuring structures.
Time-lapse
- Time-lapse Images captured at regular intervals show slow processes such as germination, growth or cell division.
Camera traps
- Camera traps Motion-activated cameras record wildlife without disturbing it, giving data on species presence and behaviour.
GPS tracking
- GPS tracking Tags on animals record positions, which show migration routes and habitat use over time.
Spectrophotometry
- Spectrophotometry Light absorbance is measured electronically, which can be calibrated to find the concentration of a solution.
Section 3 of 5Using Technology Well
1
Choose the sensor that matches the variable and the range expected, and check that it can measure to the resolution needed.
2
Calibrate the sensor against a known standard before use, for example a pH buffer solution.
3
Set the sampling interval and total duration to suit the speed of the process being studied.
4
Check the first readings for sensible values and make sure that the probe is fully in contact with the sample.
5
Save the file with a clear name and note the units, sampling rate and calibration in the lab notebook.
| Advantage | Limitation |
|---|---|
| Frequent, objective readings | Expensive equipment |
| Remote or long recordings | Sensors need calibration and can drift |
| Large data sets easily shared | Requires power and technical skills |
Section 4 of 5Worked Example
Question
- A data logger records oxygen concentration every 5 seconds for 10 minutes.
- How many readings are taken during the 10 minutes, not counting the one at the start?
- Convert 10 minutes to seconds: 10 × 60 = 600 s.
- Divide by the sampling interval600 ÷ 5 = 120.
- If the reading at time zero is counted too, the total is 121.
Answer 120 readings after the start (121 including the reading at zero).
Section 5 of 5Exam Checklist & Tips
5.2.1 – Key Points for the Exam
- Sensor A device that converts a physical or chemical change into an electrical signal.
- Data logger A device that records sensor readings over time.
- Sampling rate How often a reading is taken.
- Calibration Adjusting an instrument against a known standard.
Common Mistakes
- Assuming that electronic readings are always accurate without being calibrated.
- Choosing a sampling interval too long to detect fast changes.
- Forgetting to record units and sampling conditions with the data.
- Thinking that more readings always mean better data, regardless of whether they are relevant.
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