Chemistry 101: Significant Figures

Significant Figures

Chemistry 101: 8th Grade Science

          Making measurements is a very important aspect of studying chemistry. Whether this be measuring the volume using a graduated cylinder, or weighing mass on a balance, or even simply measuring the length of something, making precise measurements is a very imperative piece of studying this topic. However, every experimental measurement, no matter how precise, has a degree of uncertainty to it because there I always a limit to the number of digits that can be determined. In order to keep a measurement accurate, the value recorded should use all the digits known with certainty. These specific numbers of digits are also referred to as SIGNIFICANT FIGURES. Significant figures are the numbers of meaningful digits use to express a value.

Determining the number of significant figures can normally be simple, however this can get more challenging when there are zeroes involved. Here are some rules to help you determine the number of significant figures are needed when zeroes are present: 

• Rule 1: Zeroes sandwiched between two non-zero numbers are always significant (Ex. 4.708 has 4 significant figures)
• Rule 2: Zeroes at the beginning of any number are not significant and simply act to locate the position of a decimal (Ex. 0.036 has 2 significant figures)
• Rule 3: Zeroes at the end of a number after a decimal point are significant or they would not be recorded (Ex. 183.400 has 6 significant figures)
• Rule 4: Zeroes at the end of a number before a decimal point may or may not be significant. It depends if they are part of the measurement or if they act to indicate an implied decimal place

Always remember to be mindful of significant figures when making measurements in the laboratory. They keep the data as accurate and precise as possible and help to avoid any calculation error that may result from inaccurate data!