Significant Figures

When we perform experiments, we record the measurements as values

When our measurement values are consistent, we say our data is precise.

More precise values can be very helpful because it means our experiment results do not fluctuate

This means that experiment will give almost same results every time

To measure precision, a quantity called Significant figure is used

Significant Figures are the number of digits that help us understand the precision of the measurement

All values have some significant figures and some insignificant figures

Significant figures, can easily be found with the help of some rules

Rule 1: We identify all non zero numbers in our value

All Non Zeros are significant. E.g.- 241381 has 6 significant figures

So this number has 6 significant figures

Rule 2: Now we identify zeros that are enclosed

A zero or zeros between two non zero digits are significant

So this number has 4 significant figures

Rule 3: We identify the terminal zeros

Zeros that end a number are called terminal zeros. They are insignificant.

So this number has 2 significant figures.

Rule 4- We identify the leading zeroes

Leading Zeros are 1)At the start of value 2)Immediately after a decimal They are NOT considered significant

So this number has 3 significant figures

Rule 5- We identify zeros to the right of the decimal except leading zeroes

Enclosed and terminal zeroes to the right of decimal are significant. So this number has 5 significant figures

Once we get the significant figures, we can move on to the precision of the value

The number of digits after the decimal point are called the digits of precision

201.78 has 2 digits after the decimal 7 and 8 So it has 2 digits of precision

Similarly 0.03526 has 5 digits of precision

Now we can calculate significant figures and precision of a value

Let’s calculate them for 0.05016

0.05016 has 4 significant figures

It has 5 decimal places. So it has 5 digits of precision

Revision

Significant figures are the number of digits that help us understand precision

In a value, these are significant 1) Non zero figures 2) Enclosed zeros 3) Terminal/ending zeros

Leading zeros are immediately after the decimal. They are insignificant

Zeros on right side of decimal excluding leading zeroes are significant

Precision is calculated by the number of digits after the decimal point

The End