Water clings to the glass of a graduated cylinder, and forms a slight upward curve at the top of the water level, called a meniscus. You need to measure at the bottom of the curve, because if you do it from the top, you would get a wrong reading.
Why Is Meniscus An Important Part When Using A Graduated Cylinder?
Because water clings to the side of the Graduated Cylinder and to have the exact amount you have to use a meniscus.Other wise your answer would be under or above the right answer.
When a liquid is poured into a containor it makes a downward curve so we measure the bottom of the curve.because the water grabs the sides of the glass it pulls the sides up,and because the middle of the of the containor,because there is nothing to hold onto it drops.