Significant Figures and Measurement Precision

Flashcards covering significant figures, measurement precision, reading instruments, rounding rules, and significant figure rules for calculations.

What reflects the precision of data in a reported number?

The number of digits reported.

Which is generally more precise: a bathroom scale or a lab balance, and why?

A lab balance is often more precise because it reports more specific numbers, usually with more digits after the decimal point.

What two types of digits are always present in a reported number or measurement?

Certain digits (known for sure) and estimated digits (the last digit).

When making a measurement, what is the process for determining the certain and estimated digits?

Determine the value of the increments, identify the certain digits based on known lines, and then estimate the last digit.

How should one correctly read a meniscus in a tube to ensure an accurate measurement?

Take the measurement at eye level, focusing on the bottom of the curved shape of the water.

What do significant figures represent in a measurement?

The precision of a measurement; a greater number of significant figures indicates greater precision.

In general, how do zeros at the beginning vs. at the end of a number with a decimal affect significant figures and precision?

Zeros that mark a decimal (at the beginning) are not significant, but zeros at the end after the decimal point are significant and increase precision.

What are "unlimited significant figures," and what kind of numbers possess them?

Unlimited significant figures refer to exact or defined numbers (e.g., counts of discrete objects, conversion factors within a system), which are considered to have infinite precision.

Give an example of a number that would have unlimited significant figures.

The count of 6 markers, 1000 meters in a kilometer, or the '2' in the formula "radius = diameter/2."

When rounding, what is the rule if the last digit to be dropped is 5 or more?

Round up the preceding digit.

When rounding, what is the rule if the last digit to be dropped is 4 or less?

Round down (keep the preceding digit the same).

What rule applies to significant figures when performing multiplication or division?

The result should be rounded to the same number of significant figures as the measurement with the fewest significant figures (the "weakest link" analogy).

What rule applies to significant figures (or decimal places) when performing addition or subtraction?

The result should be rounded to the same number of decimal places as the measurement with the fewest decimal places.

When performing mixed calculations involving significant figures, what mathematical principle should be followed?

PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction).