Measurement, Significant Figures & Uncertainty

Front

What are significant figures (sig figs)?

Back

Digits that carry meaning in a measurement, including the estimated last digit.

Front

What are certain digits?

Back

Digits read directly from the scales or marks.

Front

What is an uncertain digit?

Back

The last digit, which is an estimate (analog) or instrument-assigned (digital) based on the limitations of the measuring tool.

Front

Define accuracy in measurements.

Back

Closeness to the true or accepted value.

Front

Define precision in measurements.

Back

Repeatability/resolution of a tool; how finely an instrument can read.

Front

What is resolution in the context of measurements?

Back

Smallest readable increment (e.g., 1 mm on a ruler, 0.01 g on a balance).

Front

What is uncertainty in measurements?

Back

The estimated range surrounding a measured value that reflects the limitations of the measurement instrument and the experimental technique.

Front

How is uncertainty determined for analog scales?

Back

Uncertainty is usually taken as ±½ of the smallest division you can read directly.

Front

How is uncertainty determined for digital instruments?

Back

The uncertainty is taken as ±1 in the last displayed digit, which is equal to ±1 × resolution.

Front

What is percent error?

Back

Compares a measured value with an accepted or known value, showing how close the measurement is to the expected value.