Which of the following is not one of the three principles from which the metric system is based?
A number should be rounded up if _______.
What is 0.25 kilometers expressed in centimeters?
How do the prefixes in the metric system relate to the basic units?
Metric prefixes indicate how a unit compares with its basic unit by powers of ten. For example, kilo- means 1,000 times the base unit, centi- means one-hundredth, and milli- means one-thousandth. The same prefixes can be applied to different metric base units.
Explain why scientists use the metric system for scientific measurements.
Scientists use the metric system because it is a standardized system used around the world, allowing measurements to be communicated and compared consistently. Its units are related by powers of ten, so conversions are straightforward: the decimal point can be shifted rather than using complicated conversion factors.
What is the difference between accuracy and precision and which is most important to scientific measurement?
Accuracy is how close a measurement is to the true or accepted value. Precision is how close repeated measurements are to one another. Both are important for scientific measurement: results should be close to the truth and repeatable. If one must be prioritized, accuracy is generally most important, because repeated measurements can be precise yet consistently incorrect.
When converting from kilometers to meters, the decimal is moved _______.
What are the basic prefixes used in the metric system and how do they relate to the size of the base unit?
The basic metric prefixes include kilo-, hecto-, and deka-, which represent 1,000, 100, and 10 times the base unit. The base unit is the reference size. The prefixes deci-, centi-, and milli- represent one-tenth, one-hundredth, and one-thousandth of the base unit.
Explain why significant figures represent the precision of a measurement and not its accuracy.
Significant figures indicate how finely a measurement was recorded: they include its certain digits and the final estimated digit. This describes the measurement's precision or resolution. A measurement can have many significant figures and still be inaccurate if it is far from the true value; accuracy depends on closeness to that value.
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