key term - Kilogram

Definition

The kilogram is the base unit of mass in the International System of Units (SI). It is defined as the mass of the international prototype of the kilogram, a platinum-iridium cylinder kept at the International Bureau of Weights and Measures in Sèvres, France. The kilogram is a fundamental unit used to measure the amount of matter in an object and is essential for understanding systems of measurement.

5 Must Know Facts For Your Next Test

1. The kilogram is the only base unit in the SI system that is still defined by a physical artifact, rather than a fundamental constant of nature.
2. The international prototype of the kilogram is stored in a vault at the International Bureau of Weights and Measures and is used to calibrate other kilogram standards around the world.
3. Accurate measurement of mass is essential for many scientific and industrial applications, such as determining the composition of materials, calculating the force of gravity, and ensuring the proper functioning of medical devices.
4. The kilogram is used in a wide range of measurements, including the mass of food, the weight of packages, the capacity of containers, and the power output of engines.
5. The definition of the kilogram has been a subject of ongoing debate, and efforts are underway to redefine the kilogram in terms of a fundamental constant of nature, such as the Planck constant, to ensure its long-term stability and reproducibility.

Review Questions

• Explain the importance of the kilogram as a base unit in the International System of Units (SI).
  • The kilogram is a fundamental unit of mass in the SI system, which is the most widely used system of measurement worldwide. Accurate and consistent measurement of mass is essential for a wide range of scientific, industrial, and commercial applications, from determining the composition of materials to ensuring the proper functioning of medical devices. The kilogram serves as the foundation for many other derived units, such as force, energy, and power, making it a critical component of the SI system.
• Describe the current definition of the kilogram and the challenges associated with it.
  • The kilogram is currently defined by the mass of the international prototype of the kilogram, a physical artifact made of platinum-iridium alloy and kept in a vault at the International Bureau of Weights and Measures in Sèvres, France. This definition has been in use since 1889, but it has been the subject of ongoing debate due to the potential for the prototype to change over time, as well as the difficulty in precisely reproducing the kilogram definition. As a result, efforts are underway to redefine the kilogram in terms of a fundamental constant of nature, such as the Planck constant, to ensure its long-term stability and reproducibility.
• Analyze the relationship between the kilogram and other units of measurement in the metric system, and explain how they are used to measure various quantities.
  • The kilogram is the base unit of mass in the metric system, which also includes the meter as the base unit of length and the liter as the base unit of volume. These three base units are used to derive a wide range of other units, such as the gram (one-thousandth of a kilogram), the centimeter (one-hundredth of a meter), and the milliliter (one-thousandth of a liter). The relationships between these units allow for the measurement of various quantities, such as the mass of an object, the volume of a liquid, or the density of a material. Understanding these connections and the ability to convert between different units is essential for accurate and meaningful measurements in scientific, industrial, and everyday applications.

Related terms

Gram:

A unit of mass in the metric system, equal to one-thousandth of a kilogram.

Metric System:

A decimal-based system of measurement that uses the meter, liter, and gram as its base units.

Mass: The amount of matter in an object, measured in units such as the kilogram.