Significant Figures and their Importance Revision Notes

In these revision notes for Significant Figures and their Importance, we cover the following key points:

• What are significant figures?
• How to find the number of significant figures in a given numerical value?
• How to round up a number to the required number of significant figures?
• Why are significant figures so important in measurements?

Significant Figures and their Importance Revision Notes

Significant figures represent the accuracy with which we know the values of a measurement. The accuracy of an apparatus is equal to the smallest unit it can measure.

There are five basic rules to find the correct number of significant figures in a given numerical value obtained during a measurement. They are:

1. The zeroes at the end of a whole number are not counted.
2. Zeroes at the beginning of a decimal number are not counted.
3. All zeroes between two non-zero digits are always counted.
4. All zeroes at the end of a decimal are always counted.
5. If the measurement value is written in standard form (scientific notation), only the numerical part before the powers of ten is counted. The exponential part is not considered.

If we have a combined measurement (for example we have the length and width given and want to calculate the area, first we must write both numbers at the same degree of accuracy (to the accuracy of the least accurate dimension) and then doing the operations.