Final answer:
The correct answer is option 2. When selecting a micropipette, choosing one with the smallest volume range necessary is advised because micropipettes with smaller volume ranges offer greater precision. This higher precision is crucial for accurate measurements in laboratory experiments, ensuring the success of protocols requiring exact volumes of liquids.
Step-by-step explanation:
When using a micropipette, it is advisable to select one with the smallest volume range necessary to meet your needs because micropipettes with smaller volume ranges have greater precision. This is because micropipettes are designed to dispense very small volumes of liquid with high accuracy. The smaller the volume range of the micropipette, the more refined the graduations on it can be, leading to more precise measurements. For example, a 2-20 μl micropipette can measure small volumes much more accurately than a 20-200 μl micropipette, as the latter is designed to handle a wider range of volumes and thus has larger increments between the smallest measurable amounts. Precision is critical in experiments like titrations or adding reagents to a reaction, where the accurate measurement of volume can affect the outcome of the experiment.
Moreover, selecting a micropipette with a suitable volume range for your requirements is similar to applying the principle that you want to use the unit of measurement that most closely matches the object you are measuring – for instance, not measuring the volume of a swimming pool in milliliters. Similarly, you wouldn't want to measure 5 μl with a 1000 μl pipette as this would likely lead to a significant error rate due to the poor resolution of the pipette at such a small volume compared to its maximum capacity.
In practice, having several micropipettes of different ranges in a laboratory setting is common, allowing for both small and large volumes to be measured with the appropriate tool, ensuring accuracy and precision in various protocols such as cell growth using an orbital shaker or adding reagents in microcentrifuge tubes.