Measurements are only as accurate as the instrument that is used to make them. For example, if a metric ruler is divided into millimeters, then a more precise measurement, such as micrometers, cannot be made. They determine how precise a measurement is. Significant figures are related to …show more content…
The text book includes a rule about rounding when the last digit is a 5, stating that if the preceding digit is an odd number, it gets rounded up and if it is an even number, it remains the same. We will not be following these rules, but rather sticking to the rule already mentioned: if the number following the last significant number is greater than or equal to 5 it gets rounded up and if the following number is less than 5, it remains the same. Another one of our rules that differs from the textbook states that if a number, like 1000, has a decimal point behind it (1000.), then those zeros are significant figures. This is not true for us. A number like 1000 has only 1 significant figure. In order for this number to be expressed with four significant figures, it needs to be written in scientific notation, 1.000 x 103.
If a number needs to be reduced to a certain amount of significant figures, refer to the following number to determine whether to round the number up or down. If the following number is less than 5, round down. If the number is greater than or equal to 5, round up. For example, the number 1.2564 expressed in 2 significant figures would be 1.3, because the following number is 5. The number 500.03, rounded to 1 significant figure should be expressed as 5 x …show more content…
For example, when adding 40.5678 cm (6 significant figures) and 3.45 cm (3 significant figures), the answer is 44.0178 cm. This answer contains 6 digits, but must be expressed only to the hundredth place, 44.02 cm. Although 3.45 only has 3 significant figures, the answer has 4 significant figures, due to the fact that the least precise piece of data was only measured to the hundredth place.
In multiplication and division problems, answer contains the same amount of significant figures as the figure in the problem with the least amount of significant figures. When multiplying 40.000 cm (5 significant figures) and 54.3 cm (3 significant figures) and 1.175 cm (4 significant figures), the answer is 2552.1 cm3. The final answer must be expressed using only 3 significant figures this answer can be written 2550 cm3, but this can lead to some confusion as to whether it has 3 or 4 significant figures, therefore the final answer should be expressed as 2.55 x 103