It would seem that such a ruler? A simple tool for measuring length. And what significance does it have in our life! It is difficult to do without a schoolboy, engineer, draftsman.
A bit of history
In its usual guise, as we used to see it, it has been known since the time of the French Revolution. This is more than two hundred years ago. But its appearance can be dated to an even earlier period. During excavations of the ancient city of Pompeii, archaeologists found attributes similar to a ruler - combined smooth planks.
And the Middle Ages testifies to the existence of this amazing instrument, which was played by thin plates of lead. And in Ancient Russia, metal rods were used for measurement.
Of course, we can now judge that it was extremely inconvenient to use them, but such is the history of the appearance and development of the line.
Definition, material of manufacture
What is a ruler? This is a device that reproduces a straight line on a plane, with the aim of making spatial measurements. Units of measurement are plotted along its outer border, which are the millimeter and centimeter, and an inch in the English ruler.
It can be made of different materials: plastic (distinguish between transparent and opaque, flexible and rigid), cardboard, metal and even fabric.
To determine more accurate linear dimensions, it is better to use a metal ruler. Because plastic at the slightest heating changes in size, and wooden under the influence of moisture tends to swell. It is more convenient to use a plastic transparent ruler, since it does not obscure the image. But she smudges the pattern more with wood, which requires constant cleaning from pollution.
The metal ruler is made of steel sheet with a polished surface and has a chrome coating that does not lend itself to corrosion.
Ruler length
After we figured out what a measuring ruler is, we can talk about its length.
According to GOST, a special scale is applied to its surface. It can be from 150 to 3000 mm long. Rulers with a length of 300, 500 and 1000 mm are more in demand.
Externally, all the lines are identical, have a surface width of 18 to 40 mm depending on the length. Their thickness is either half or one millimeter. All contain dividing lines equally spaced from each other, the price of which is 1 mm.
The zero stroke is the reference point in measuring instruments. It is usually located at the left end of the ruler and is considered the end measure.
On a metric ruler can be located not one, but two scales. There are such measuring instruments on which zero division is present both on the right and on the left.
So, the ruler with divisions is the simplest element for drawing with a scale marked on it, thanks to which you can build geometric shapes, perform linear measurements and calculations.
The system of measures used in the metric line
The meter is the largest measuring unit, and centimeters act as the fundamental metric units of the system. One meter has a hundred centimeters.
Large divisions, under which the numbers are located, indicate centimeters (cm). Typically, the standard ruler length is thirty centimeters. And the distance between large marks is equal to a centimeter.
Small strokes on the surface of the ruler, located between large divisions, indicate millimeters. One centimeter has ten millimeters (mm).
As an example, let’s analyze the task: “Measure with a ruler the length of a ballpoint pen.” How to do it?
The pen should be placed on a hard surface, and measurements can be made with a ruler.
You need to attach the ruler to the left edge of the handle, while making sure that its end is aligned with the zero mark. This side must be fixed with the left hand, and with the right to adjust the position of the end of the measuring device.
The extreme number close to the end of the measured object, and will be its length. Suppose it is 15 centimeters, and the remaining small divisions following the limit of the last marked digit, of which four, will mean millimeters. Thus, the handle length is 18.4 mm.
Measuring the length of an object is a method carried out by applying a ruler to an object. It, in turn, is subject to measurement by comparing its length with the value of the measure. To take measurements from a person, to sew clothes, it is better to use a meter, elastic tape. Well, if you need to measure a large distance, it is more convenient to use tape measure. And in conclusion, what is a metric ruler? This is a measuring device on which readings are read from left to right. The number found on the right will determine the length. Indications are recorded as decimal fractions, for example, 0.5 cm.