Why Are Significant Figures Important?

Significant figures tell readers of a scientific report about the precision of obtained data. Scientists use significant figures in measured quantities where it is impossible to know an exact number. One pitfall scientists must be aware of is that reporting data with more significant figures than the equipment used allows indicates an accuracy that is not achievable.

According to “Scientific American,” significant figures have real world application. Since everything in the real world is a measurement, “significant figures are one of the ways we can quantify the precision of real world measurements.” One question that arises with significant figures relates to zeros. When zeros are place holders, they are not significant. However, if the measurement ends with one or more zeros, the individual reporting the data needs a way to indicate that the number is significant. Zeros one adds at the end of a number after the decimal point are significant. In some instances, the individual reporting the data helps the reader by underlining or placing a bar over the last significant figure of a number with tailing zeros to the left of the decimal. A decimal point at the end of a whole number indicates all values to the left of the decimal are significant. When the individual reports a number in the normalized form of scientific notation, there are no leading or trailing zeros, so all numbers are significant.