Functions and uses of straightedge

1. Rulers are usually used to measure short distances or draw straight lines.

2. Rulers are widely used in mathematics, surveying, engineering and other disciplines, and have the function of accurately measuring ruler gauges.

3. The ruler is used to measure straightness and flatness by light gap method, and can also be used to check length and size together with gauge block. ?

Rulers are usually made of rolling bearing steel.

Ruler, also known as interval ruler, is a very common tool for measuring length. This kind of stationery is very common, almost every primary school student has one, which is usually used to measure short distances or draw straight lines.

Extended data

Application mode

1, before use

Do three things, that is, first look at whether the zero scale of the scale is worn, and if it is worn, re-select a scale value as the starting point of measurement.

Secondly, look at the measuring range (range) of the scale. In principle, the length measurement needs a measurement. If the measuring range is smaller than the actual length, the ruler needs to be moved many times, which will lead to a large error.

Finally, it depends on the minimum scale value of the scale. The length value represented by the minimum scale not only reflects the different precision of the scale, but also relates to the validity of the measurement results. The measurement range and minimum calibration value should be selected according to the actual measurement requirements.

2. When in use

Attention should be paid to correct placement and correct observation when using.

The key to correct placement is: the edge of the ruler is aligned with the measured object, which must be aligned and overlapped, and cannot be skewed; The facet of the ruler must be close to the measured object and cannot be "suspended".

The key to correct observation is that the line of sight is in front of the terminal scale line and perpendicular to the small plane, so that the number of large cells and small cells can be seen clearly.

References:

Baidu encyclopedia-ruler