Identifying Measurements with Three Significant Figures- A Comprehensive Guide

Which of the measurements contain three significant figures is a common question in scientific and mathematical fields. Significant figures, also known as significant digits, are essential in determining the precision and accuracy of a measurement. In this article, we will explore the concept of significant figures and discuss how to identify measurements with three significant figures.

Significant figures are digits in a number that carry meaning in terms of precision. They are used to express the level of certainty in a measurement. The rules for determining significant figures are as follows:

1. All non-zero digits are significant. For example, in the number 123, all three digits are significant.
2. Zeros between non-zero digits are also significant. For instance, in the number 102, all three digits are significant.
3. Leading zeros (zeros before the first non-zero digit) are not significant. For example, in the number 0.0023, only the digits 2, 3, and the trailing zero are significant.
4. Trailing zeros (zeros after the last non-zero digit) are significant if they are at the end of a number with a decimal point. For example, in the number 250.0, all four digits are significant.
5. Trailing zeros without a decimal point are not always significant. However, if the number is written as a number with a known quantity, then the trailing zeros are significant. For example, in the number 1000 g, the trailing zero is significant because it indicates that the measurement is known to the nearest gram.

Now, let’s identify measurements with three significant figures:

1. 2.50 g: This measurement has three significant figures because all three digits are non-zero and the trailing zero is significant due to the decimal point.
2. 0.0234 kg: This measurement has three significant figures because the first three digits are non-zero, and the trailing zero is significant due to the decimal point.
3. 123.0 mL: This measurement has four significant figures, so it does not meet the requirement of three significant figures.
4. 0.00567 kg: This measurement has four significant figures, so it does not meet the requirement of three significant figures.

In conclusion, identifying measurements with three significant figures is crucial for maintaining accuracy and precision in scientific and mathematical calculations. By following the rules for determining significant figures, you can ensure that your measurements are expressed correctly and consistently.