Get Measurement Estimating One Place Beyond

The benchmark technique is a commonly used method for estimating distances. It involves using a known distance as a reference point to estimate an unknown distance. This technique is particularly useful when direct measurement is not feasible or accurate.

The first thing to realize is that there is no such thing as a perfect measurement. Even when using expensive lab equipment there some degree of uncertainty in measurement. The general rule of thumb is: you can estimate one more digit past the smallest division on the measuring device.

The bottom ruler contains no millimeter markings, so the tenths digit can only be estimated, and the length may be reported by one observer as 2.5 cm. However, another person may judge that the measurement is 2.4 cm or perhaps 2.6 cm. While the 2 is known for certain, the value of the tenths digit is uncertain.

Determining the Number of Significant Figures The number of significant figures in a measurement, such as 2.531, is equal to the number of digits that are known with some degree of confidence (2, 5, and 3) plus the last digit (1), which is an estimate or approximation.

In using any measuring device, an estimate of one decimal place past the marks should be made, thus the uncertainty in any measurement is in the last digit.

Use subdivisions. Length, volume and area measurements all lend themselves to this technique. For example, if the wall has no useful chunks, it can be mentally divided in half and then fourths or even eighths until a more manageable length is arrived at.

the last digit of any measurement is estimated, and it is this estimated digit that reflects uncertainty. The more decimal places there are the less uncertainty there is. For example, 29.2 has more uncertainty than 29.25. Only one estimated digit is ever recorded as part of a measurement .