## Introduction

We need to understand the concept of “significant figures” because __measurements need to be recorded in a proper way.__

Here is an example to make

things easier to understand:

You must be knowing that ruler, vernier calipers and micrometer screwguage all measure length. However they measure length to different amount

of accuracy.

Instrument | Accuracy |
---|---|

Ruler | 1 millimeter (1 mm) |

Vernier calipers | 10^{th} of a millimeter(0.1 mm) |

Micrometer screwguage | 100^{th} of a millimeter(0.01 mm) |

Let’s say the __actual__ diameter of a wire is 2.012 millimeters.

So if you measure the diameter of a wire using a ruler, you may record the value as 2mm __but not 2.0mm__ because the ruler will not tell you about the tenth

of a millimeter.

Similarly, if you use vernier calipers, you may write the measurement as 2.0mm but you should not write 2.01mm because vernier calipers cannot

measure accurately a hundredth of a millimeter.

In the same way the recorded value from a micrometer screwguage shall be 2.01mm.

Next step: Identifying significant figures