Answer:
1. Control of External Factors: One precaution that should be taken when conducting an experiment with an extension spiral spring is to control external factors that may affect the accuracy of the results. This can include controlling temperature, humidity, and air pressure to minimize any environmental changes that may affect the spring's behavior.
2. Proper Measurement Techniques: Another precaution to take is to use proper measurement techniques. This can include using accurate and precise measuring instruments, such as a ruler or caliper, and properly measuring the length and force of the spring's extension.