key term - Kilogram

Definition

A kilogram is the base unit of mass in the International System of Units (SI), defined as being equal to the mass of the international prototype of the kilogram, a cylinder made of platinum-iridium. This unit is fundamental in the field of measurements, serving as a standard to quantify mass and weight across various scientific and engineering applications.

5 Must Know Facts For Your Next Test

1. The kilogram is the only SI base unit with an SI prefix (kilo) as part of its name, making it unique among other units.
2. The definition of the kilogram was updated in 2019 to be based on physical constants, specifically the Planck constant, rather than a physical object.
3. One kilogram is approximately equal to 2.20462 pounds, which helps in converting between metric and imperial systems.
4. Kilograms are widely used in many fields including science, engineering, and commerce, making it a crucial unit for global trade.
5. In laboratory settings, precision balances are used to measure mass in kilograms with high accuracy.

Review Questions

• How does the definition of a kilogram relate to the standardization of measurement in scientific fields?
  • The kilogram's definition has evolved to ensure consistency and accuracy in scientific measurement. Initially based on a physical object, it was redefined in 2019 using the Planck constant, linking it to fundamental physics. This standardization allows scientists and engineers worldwide to communicate and replicate results with confidence, as they can rely on a universally accepted unit for mass.
• Discuss the practical applications of the kilogram in both everyday life and specialized fields such as engineering and science.
  • In everyday life, kilograms are commonly used for weighing groceries, food items, and personal weight. In specialized fields like engineering and science, kilograms are critical for calculations involving force, energy, and material properties. For instance, engineers must consider mass when designing structures to ensure they can support loads effectively, while scientists use kilograms for experiments that require precise measurements.
• Evaluate the implications of redefining the kilogram based on physical constants rather than a physical artifact on global scientific practices.
  • Redefining the kilogram using physical constants has significant implications for global scientific practices. It enhances measurement precision and stability over time since physical artifacts can change due to wear or environmental factors. This shift fosters greater international collaboration and data sharing across scientific disciplines by ensuring that all researchers have access to an accurate and consistent standard for mass measurements, thus improving the reliability of experimental results and technological advancements.

Related terms

Gram:

A gram is a metric unit of mass equal to one-thousandth of a kilogram, commonly used for measuring smaller quantities.

Newton: A Newton is the SI unit of force, defined as the force required to accelerate a one-kilogram mass by one meter per second squared.

Mass:

Mass is a measure of the amount of matter in an object, typically expressed in kilograms or grams.