What is a ruler? Concept, length, example of measurement

It would seem that such a ruler? A simple tool for measuring length. And what importance does it have in our lives! Without it, it is difficult to get along with a schoolboy, an engineer, or a draftsman.

A bit of history

In its usual appearance, as we used to see it, it has been known since the Great French Revolution. It's more than two hundred years ago. But its appearance can be dated even earlier. During the excavations of the ancient city of Pompeii, archaeologists found attributes similar to the ruler - combined smooth plaques.

And the Middle Ages testifies to the existence of this amazing instrument, in the role of which thin plates of lead protruded. 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 this is the story 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, for the purpose of performing spatial measurements. On its outer border, units of measurement are marked, in the role of which millimeter and centimeter protrude, and in the English ruler - inch.

It can be made of different materials: plastics (distinguish transparent and opaque, flexible and rigid), cardboard, metal and even fabric.

To determine the more accurate linear dimensions, it is better to use a metal ruler. Because the plastic at the slightest heating varies in size, and the wooden one under the influence of moisture has the property of swelling. Plastic transparent ruler is more convenient to use, because it does not cover the image itself. But it is more wooden stains the picture, which requires constant cleaning of the contaminants.

The metal ruler is made of steel sheet with a polished surface and has a chromium coating that does not lend itself to corrosion.

Length of ruler

After we figured out what a measuring ruler is, you can talk about its length.

According to GOST, a special scale is applied to its surface. Can be from 150 to 3000 mm in length. More demanded rulers, the length of which is 300, 500 and 1000 mm.

Externally, all the rulers are identical, they have a surface from 18 to 40 mm wide, depending on the length. Their thickness is either half or one millimeter. All contain equidistant strokes, the price of which is 1 mm.

Zero touch is the starting point in the measuring instruments. It is, as a rule, at the left end of the ruler and is considered an end measure.

On the metric ruler there can be not one, but two scales. There are such measuring devices on which zero division is available both on the right and on the left.

So, the ruler with the divisions is the simplest element for drawing with the scale marked on it, thanks to which it is possible to build geometric figures, perform linear measurements and calculations.

The system of measures used in the metric ruler

The meter is the largest measuring unit, and in the role of the fundamental metric units of the system are centimeters. One meter is one hundred centimeters.

Large divisions, under which the values of numbers are located, denote centimeters (cm). Typically, the standard length of the ruler 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, denote millimeters. One centimeter has ten millimeters (mm).

As an example, let's analyze the task: "Measure the length of the ballpoint pen with a ruler". How to do it?

The handle should be placed on a hard surface, and measurements can be made with a ruler.

It is necessary to attach the ruler to the left edge of the handle, while making sure that its end is level with the zero mark. This side must be fixed with the help of the left hand, and the right one must be adjusted to the position of the end of the measuring device.

The extreme number, close to the end of the measured object, will be its length. Let's say it's 15 centimeters, and the remaining small divisions following beyond the last marked digit, four of which, will be millimeters. Thus, the length of the handle 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 to be measured 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, an elastic band. Well, if you want to measure a long distance, it is more convenient to use a tape measure. And finally, what is a metric ruler? It is a device for measuring, in which readings are read from left to right. The number found on the right will determine the length. The readings are recorded as a decimal fraction, for example, 0.5 cm.