4.2.1.3 Required practical 3 — Resistance

What you do (method)

• Measure V and I as you change one variable:
  • wire length (or thickness)
  • temperature (thermistor)
  • light intensity (LDR)
• Calculate resistance each time: R = V / I.
• Plot graph (e.g. R vs length / R vs temperature / R vs light level) and describe the trend.

Common mistakes

• Not controlling variables (same wire material/diameter, same voltage supply, etc.).
• Using subjective light levels instead of measured distance/lux (if asked).

Support videos

• FreeScienceLessons resistance practical search: https://www.youtube.com/results?search_query=freesciencelessons+resistance+thermistor+LDR+required+practical