People weigh things all the time with a balance. We often confuse this with mass, however. If you were to take a balance with you on the moon or other spots without gravity, your weight would change but your mass wouldn’t.
The metric system uses specific symbols for prefixes and units to allow measurements to be made across languages and alphabets. These symbols include the metre for lengths, kilogram for masses and litre for liquid capacities.
What is Mass?
Mass is the amount of matter, or “stuff,” in an object. An object’s mass determines its inertia, which is its resistance to acceleration when acted upon by a force. It also determines the strength of an object’s gravitational attraction to other objects.
Prior to the development of atomic and particle physics, mass was believed to be intrinsic and unchanging. With the introduction of Einstein’s special theory of relativity, however, mass underwent a radical revision. It was found that rest mass is interconvertible with energy, and that an object’s mass will increase at speeds that approach the speed of light.
Although the terms mass and weight are often used interchangeably, they are not the same. Mass is a scalar quantity, while weight is a vector quantity that is directed toward the center of the Earth or other gravity well. In space, where no gravity exists, an object’s weight can be zero. The acceleration of an object in free fall is proportional to its mass, but the same object will not have the same weight at different points on the Earth because it is not an exact spherical shape.
How is Mass Measured?
Measurement of mass is most commonly done using a balance. During the process, an unknown item is placed on the scale and compared to a stainless steel mass standard. The resulting value represents the item’s conventional mass, which is its true mass minus a degree of buoyancy.
Prior to the discovery of atoms and particle physics, an object’s mass was viewed as intrinsically related to its amount of matter. Since then, it has been discovered that different atoms and elementary particles, even though theoretically they have the same amount of matter, have differing masses.
Another important distinction is that while weight depends on the gravitational force of an object’s location, mass does not change with changes in velocity. Energy can, however, change an object’s mass into non-matter energy like light, heat, and sound. The only exception is that an object’s mass will increase with its speed approaching the speed of light. This is also known as its rest mass.
What is the Unit of Mass?
The SI unit of mass is the kilogram (kg), and it’s used in both scientific contexts as well as daily life. Several other units can be used to measure mass, but these are only decimal multiples or fractions of the kg.
Mass is an intrinsic property of matter, while weight is the force that an object feels pulled down by gravity. Because of this, mass and weight are two different quantities.
The gram, the smallest of the SI base units, is the most common unit for measuring mass. It’s also called the metric gram or kilogram. Other units that can be used to measure mass include the tonne (or metric ton) and the atomic mass unit (amu or u). Some scientists argue that a new definition of the kilogram is needed, one that is based on an invariable property of nature instead of on a physical artifact. They propose that this be done by fixing the value of Planck’s constant h, which is related to both mass and the speed of light.
What is the Formula for Measuring Mass?
The basic formula for calculating an object’s mass is to multiply its weight by its gravitational acceleration. This acceleration can be found using the equation W = g, where weight is measured in Newtons (N), mass is measured in kilograms (kg), and g is the gravitational acceleration of Earth, which is approximately 9.8 m/s2.
It is important to note that while size is related to an object’s volume, it is not a factor in its mass. An inflated balloon with more air may have more volume, but it will also have more mass than a golf ball made of silver.
Another common mistake people make is to confuse mass and weight. While weight is influenced by gravity, mass remains the same regardless of the environment. For this reason, you would weigh less on the moon than on Earth, but your mass will remain the same.