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
Letâ€™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