Mass is the amount of matter contained in a physical body. It determines a body’s resistance to acceleration and the strength of its gravitational pull.
Mass can be measured with simple spring scales that take g into account. However, this method is not very accurate. It is also subject to chemical attack, loss, and damage.
Metric system
In most countries of the world, people use the metric system (or SI) to measure length, liquid volume, and mass. They also use derived units based on the base units of kilogram, meter, kelvin, second, ampere, and candela. These derived units have multiples and submultiples, just like the base measurement of time, the minute and hour, and the angular measure, degree and arcsecond, which are both sexagesimal.
The metric system is based on 10. Each unit gets larger by 10 times as you go up the scale, so 1 kilogram is 1000 grams. The basic metric unit of length is the meter, which is slightly longer than your yardstick. The basic metric unit of mass is the gram, which is about the same size as a regular paperclip. The metric system uses decimals instead of fractions, and it is easy to convert among metric units using the factor label method. This method is particularly useful for converting metric measurements to the U.S. customary system.
Units of mass
In the metric system, the unit of mass is the kilogram. The kilogram is one of the base SI units, along with the meter for length and the second for time. These units can be multiplied together to create other derived SI units, like the cubic centimeter for volume.
It is important for students to understand that the concept of mass is different from weight. In physics, mass is a property of an object and determines its resistance to acceleration when a force is applied. Weight is a measure of the force that gravity exerts on an object, and this force is dependent on location.
An object has the same amount of matter regardless of where it is in space, so it has the same amount of mass. However, the same object will weigh less on the Moon than it does on Earth because of the lower gravitational pull.
Symbols
A standardized system of measurement is vital for the accurate and reliable testing and analysis of physical objects. In addition to providing scientific accuracy, the metric system also allows for consistent and clear communication of results.
The metric system is used worldwide in science, technology, industry, and everyday commerce. Its international standard is coordinated by the International Bureau of Weights and Measures (Bureau internationale des poids et mesures, or BIPM).
Symbols for all metric units are written in lowercase letters except when a prefix letter is added to the unit name. Prefix letters such as kilo and milli are added to the unit names to create larger or smaller units by factors of powers of 10.
All metric units are coherent, meaning that their dimensions are related to each other by simple multiplication and division. However, there are some derived SI units that are not strictly part of the metric system. These include angular velocity and density.
Applications
Mass measurement is crucial to a wide variety of scientific analyses. It is used to determine the atomic and molecular makeup of objects, to identify unknown compounds through their molecular weight determination, and to quantify known compounds in chemical synthesis.
Many different types of mass measurement systems exist, each with a unique set of applications. Each technique has its own monikers, but they all use the same fundamental principle of directly comparing masses to determine their difference. A simple scale is an example of this method.
Other more advanced instruments can perform complex and time-consuming analysis to obtain precise measurements. One of these is the mass spectrometer, which is often combined with other analytical techniques. This combination is referred to by a compound acronym, such as MALDI-TOF (matrix-assisted laser desorption/ionization with time-of-flight mass analyzer). Other popular methods include neutral loss scans and precursor ion scans.