Question 89

Measurements should be taken at the bottom of the meniscus at eye level.

When measuring liquids in a graduated cylinder, it is important to read the measurement at the bottom of the meniscus to ensure accuracy.

A) top of the meniscus at eye level

Measuring at the top of the meniscus is incorrect because it does not provide an accurate reading of the liquid volume. The meniscus curves downward due to surface tension, and reading from the top can result in an overestimation of the liquid level.

B) bottom of the meniscus at eye level

This is the correct method for measuring liquids in a graduated cylinder. By reading the bottom of the meniscus at eye level, the technician ensures that the measurement reflects the true volume of the liquid, minimizing errors caused by parallax.

C) top of the meniscus below eye level

Reading the top of the meniscus below eye level is also inaccurate. Similar to option A, this method can lead to an overestimation of the liquid volume due to the curvature of the meniscus, compounded by the angle of the viewing position.

D) bottom of the meniscus below eye level

While this option suggests reading the bottom of the meniscus, doing so below eye level can introduce parallax errors. Accurate measurements require the observer's eye to be level with the bottom of the meniscus to avoid misinterpretation of the liquid level.

Conclusion

The correct approach is to measure the liquid at the bottom of the meniscus at eye level, as this method yields the most accurate and reliable readings. All other options either misinterpret the meniscus's curvature or involve improper viewing angles, leading to potential measurement inaccuracies.