Question

1.4 measurement uncertainty, accuracy, and precision
define:
exact number

defined number

meniscus

significant figures

accuracy

precision

Explanation:

1. Exact Number: A value with no measurement uncertainty, a definite count or defined value.
2. Defined number: A value established by a definition, not measured (e.g., unit conversions like 1 meter = 100 cm).
3. Meniscus: The curved surface of a liquid in a narrow container, used to take accurate volume readings.
4. Significant Figures: Digits in a measured value that carry meaning about its precision.
5. Accuracy: How close a measured value is to the true/accepted value.
6. Precision: How close repeated measurements are to each other.

Answer:

1. Exact Number: A value with no measurement uncertainty, either a precise count or a defined value.
2. Defined number: A value set by official definition, not determined by measurement.
3. Meniscus: The curved upper surface of a liquid contained in a narrow tube/container.
4. Significant Figures: The meaningful digits in a measured quantity that reflect its precision.
5. Accuracy: The degree of closeness of a measured value to the true or accepted reference value.
6. Precision: The degree of consistency between repeated measurements of the same quantity.