Measuring Volume Using a Graduated Cylinder

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- [Instructor] Welcome to Measuring Volume

Using a Graduated Cylinder.

Graduated cylinders come in various sizes.

All are read by measuring

the lowest portion of the meniscus.

The meniscus is the
curved surface of a liquid

as it sits in a graduated cylinder.

A meniscus is most often concave

because liquid molecules

are more attracted to
glass than to each other.

Adhesive forces are stronger
than cohesive forces.

To measure the volume of a
liquid in a graduated cylinder,

read the level at the
bottom of the meniscus.

When measuring liquid volume,

it is important to get eye level

with the bottom of the meniscus.

To read a cylinder,
you must know the value

of each measuring line.

For example, in a 100 milliliter cylinder,

there are 10 subgraduates
between 50 and 60.

Therefore, the value of each
subgraduate is one milliliter.

In this picture of a 25
milliliter graduated cylinder,

you can see that there are 10 subgraduates

between each number.

The task is to find out

how much each measuring line is worth.

In this example, we can
compute the difference

between the graduate numbers
10 and 15, which is five.

Take that number and
divide it by the number

of subgraduates between them, which is 10,

Five divided by 10 equals 0.5,

so each mark on this graduated cylinder

is worth 0.5 milliliters.

The volume in this example
reads 11.5 milliliters.

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In this example of a 10
milliliter graduated cylinder,

there are 10 subgraduates

between the numbers six and eight.

To determine the value
of each subgraduate,

subtract six from eight to get two,

then divide two by the 10 subgraduates.

Two divided by 10 equals 0.2.

Each sub graduate has a
value of 0.2 milliliters.

The significant figures in a measurement

consist of all the certain
digits in the measurement

believed to be correct by the
person doing the measuring,

plus one uncertain or estimated digit.

This means we estimate
one decimal place past

the smallest scale division

inscribed on the graduated cylinder,

so the recorded measurement
will be one digit more accurate

than what the cylinder displays.

In this example, an appropriate
reading of the volume

is 13.5 milliliters.

We now have three significant figures.

We are certain of the one and the three,

and the five we had to estimate.

Let's say our volume reading

is at the 11 milliliter marking,

we still need to add an additional
estimated digit of zero,

so the recorded measurement
would be entered

as 11.0 milliliters.

Practice reading the graduated cylinders

in the following four examples.

Pay attention to the numbers
and graduations between each.

See if your volume readings are correct.

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You have completed this learning activity,

Measuring Volume Using
a Graduated Cylinder.