How do you read a buret meniscus correctly?

Read the volume at the bottom of the meniscus with your eye level with the curve and interpolate between the closest scale marks to estimate the last digit, then subtract the initial buret reading from the final reading to get the delivered volume.

Think of the meniscus like a little smile or frown of the liquid at the top of the tube; you always line your eye up with the bottom of that smile for watery liquids so you do not get tricked by angle. Put the buret on a steady stand so it is perfectly vertical, and bring your eye exactly even with the meniscus so you avoid parallax error which makes the number look higher or lower. Look at the nearest marks above and below the bottom of the curve and count the tiny divisions between them so you can estimate the last digit rather than guessing extra precision. If the meniscus sits halfway between two marks you record the midpoint value, and if you are using a liquid like mercury that curves the other way you read the top of the curve instead.

A common mistake is reading from above or below the meniscus which gives parallax error, so move your eye to the same level as the meniscus before you record the number. Another mistake is not clamping the buret vertically which tilts the meniscus and shifts the reading, so always secure the buret on a stand and check it is straight. Students also sometimes forget to subtract the starting reading from the ending reading to find the actual volume delivered, so write down the initial reading and subtract it carefully when you finish.

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Proper Buret Meniscus Reading Techniques

1. Line eye with bottom of meniscus
2. Use steady vertical stand
3. Avoid parallax error
4. Interpolate between nearby scale marks
5. Estimate last digit reasonably
6. Record midpoint if halfway
7. Read top for convex liquids

Common Buret Reading Mistakes

1. Parallax error from wrong eye level
2. Buret not vertical or unstable
3. Forgetting to subtract initial reading

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