# How To Read a Ruler

How to read a ruler - In everyday life, a long word is used for various purposes, eg longevity related to long lifetime, novel length in the literary world express number of pages or word count. In science, the length denotes the distance between two points, for example, the length of the side of a triangle is the distance between two vertices of a triangle. To know the length of something, do we have to measure it? Can the length of something be known just by looking at it?
To get accurate results about the length of an object, then the required of the measurement. Length is the distance between two points.
Measuring the length of non-standard done with measuring instruments in the form of fingers, span, fathoms, arms, steps, and cubits. Measurements like that, the results will be different because the span, arms, steps, and cubits of each person are different.
Measuring lengths with standard units should use measuring instruments such as the ruler, meter, vernier caliper and micrometer screw. On this occasion, we will learn how to read a ruler precisely and accurately. For that, please take a good look at the following explanation.
There are two types of a ruler: ruler English or fraction, and ruler metric or decimal ruler. Reading this ruler may at first glance look complicated because of the many small lines on the line, but actually how to read the ruler is quite simple. Follow these guidelines and you will no longer have trouble making measurements with any kind of ruler.

#### How to Use the Ruler Metric

On the ruler, there are lines showing the measurement scale. In general, there are two measurement scales on the ruler, which are centimeters (cm) and inches. On a centimeter scale, the shortest distance between two long lines that coincide is ten times the smallest scale (millimeters). The smallest measurement scale on the ruler is 1 millimeter, corresponding to the smallest line spacing on the ruler scale.
a ruler has a level of accuracy of half of the smallest scale owned by the ruler, which is 0.5 mm or 0.05 cm. How to measure the length of a pencil with the correct viewpoint as shown in the picture below.

#### Steps to measure the length of an object using a ruler are as follows.

1. Place the zero scale on the ruler parallel to one end of the object.
2. Look at the other end of the object, then read the scale on the ruler parallel to the tip of the object.
3. To read the scale on the ruler, your eyes should look perpendicular to the scale line marks you will read as illustrated in the following figure. This is to avoid error reading the measurement result due to a different angle of slope in viewing or called parallax error.

#### How to read a ruler cm and mm scale

Take a metric ruler. The ruler uses a metric system, which measures in centimeters and not inches. Usually, there are 30 centimeters in a ruler, which is marked with a large number in it. Between each centimeter (cm) mark, there should be 10 smaller marks called millimeters (mm).
Make sure you read the ruler from left to right. If you measure an object, align it with the left side of the ruler. The tip of the object on the right side is the size in centimeters.
Learn the 1-centimeter mark. The large number located next to the long line in the ruler signifies one centimeter. A metric ruler has 30 of these marks.
Learn the 1/2 centimeter mark. In the middle of each centimeter mark, there is a shorter line marking 1/2 centimeter or 0.5 cm. Altogether there are 60 of these lines in a ruler.
Learn the millimeter marks. Between each line 0.5 cm there are four more lines that mark 1 millimeter. There are a total of 10 lines for every 1 centimeter, with a 0.5 cm line applicable as a 5 mm line, so that every centimeter equals 10 mm. There are 300 of these signs in total on one ruler.

Some important things you need to consider in reading the scale of the ruler is about the exact numbers and the estimated numbers. The exact number is the number read by the scale of the measuring instrument. While the estimated number is a number that is not readable by the scale of the measuring instrument. This estimated number is required when the tip of one object is not exactly coincident with the scale, so we need an estimated number.
The estimated figures are obtained from a half-times the smallest scale. This estimated number is also referred to as the precision value of a measuring instrument. The scale of each 1 centimeter has 10 lines with a width of 1 mm or 0.1 cm, meaning the smallest scale of the ruler is 0.1 cm = 1 mm. Thus we get an estimate of ½ × 1 mm = 0.5 mm = 0.05 cm. Here is an example of how to read the scale of the length measurement results with a ruler.

From the picture above, it appears that the tip of the object (pencil) is not exactly coincident with the scale contained in the ruler but lies between 6.4 cm and 6.5 cm, so we need an estimated number. The results of the scale reading are as follows.
The exact figure is = 6.4 cm
Estimated score = ½ × 0.1 cm = 0.05 cm
Measurement result = Numbers + estimated figures
Thus, the length of the pencil is 6.4 cm + 0.05 cm = 6.45 cm

Tips
You need to practice to be able to read the ruler, especially in changing the number of measurement results. Remember to practice using a ruler and your skills will improve.
Be sure to always use the correct a ruler side to make the measurements.