Measurement

MEASURING LENGTH

Metre Rule

ruler is length measuring tools are often used. This instrument has the smallest scale of 1 mm or 0.1 cm. Rulers have half of the measurement accuracy of 0.5 mm smallest scale. At the time of taking measurements with a ruler, gaze must be perpendicular to the scale on the ruler and measured object. If not straight, it will cause an error in measurement, can be larger or smaller than its original size.

Vernier Caliper

Calliper is also a long and gauges used to measure the diameter of an object. Inventors calliper is an engineer Frenchman, Pierre Vernier. Calliper consists of two parts, namely fixed jaw and slide (sliding). Length scales contained in the fixed jaw is a major scale, while short on the scale of the sliding jaw is Nonius or vernier scale, named after its discoverer. The main scale has a scale in cm and mm. While the scale Nonius has a length of 9 mm and divided by 10 scale. So different from one scale Nonius with the scale of the main scale is 0.1 mm or 0.01 cm. Thus, the smallest scales on the calliper is 0.1 mm or 0.01 cm.

Micrometer Screw Gauge

Micrometer screw is used to measure thin objects, such as paper thickness and diameter of a hair. Micrometer screw consists of two parts, namely the casing (fixed shaft) and the outer casing (screw shaft). Length scale on the shaft remains a major scale, while the screw shaft is Nonius scale. The main scale micrometer screw has a scale in millimeters, whereas noniusnya scale is divided into 50 parts. One section on a scale Nonius has a value of 1/50 × 0.5 mm or 0.01 mm. So, micrometer screw has a higher accuracy than the two tools mentioned earlier, namely 0.01 mm.

MEASURING TIME

The tools used to measure time is watch and stopwatch.

Watch
Watches are often used by people in everyday life. On his watch, there are three needles, ie clockwise, the minute hand and second hand. Each needle pointed to a different scale.

One scale on the clock different scales. One scale shows the hours, the minutes showed the scale, and the scale shows a second.

There is another digital watches that are based on the number of vibrations made by a very small quartz crystals. Digital watches directly appoint a scale of hours, minutes, and seconds.

Stopwatch
To measure short time intervals on an ongoing events, usually using a stopwatch. This tool is typically used to practice in the laboratory or in sports.

The trick to turn the stopwatch at the time the events took place and stop until the event is completed. The figures shown are the length of time that is measured. Stopwatch started and stopped by pressing the same button on the stopwatch.

MEASURING MASS

Three Arms Balance

MEASURING TEMPERATURE

Thermometer

MEASURING FORCE

Newton meter

UNCERTAINTY

Absolute uncertainties
When marking the absolute uncertainty in a piece of data, we simply add ± 1 of the smallest significant figure.

Example:

13.21 m ± 0.01
0.002 g ± 0.001
1.2 s ± 0.1
12 V ± 1

Fractional uncertainties
To calculate the fractional uncertainty of a piece of data we simply divide the uncertainty by the value of the data.

Example:

1.2 s ± 0.1

Fractional uncertainty:

0.1 / 1.2 = 0.0625

Percentage uncertainties
To calculate the percentage uncertainty of a piece of data we simply multiply the fractional uncertainty by 100.

Example:

1.2 s ± 0.1

Percentage uncertainty:

0.1 / 1.2 x 100 = 6.25 %