Mass is a physical property of matter that is related to its size and heaviness. An object’s mass can be determined by multiplying its volume and density.
Most scientists around the world use the metric system of measurement. This includes a set of derived units that are multiplied by powers of 10. The meter and kilogram are the fundamental base units in the metric system.
What is mass?
Mass is a quantity that measures the amount of matter contained in a particle or object. It is measured in kilograms, one of the seven base units of the International System of Units (SI).
In physics, an object’s mass determines its inertia, its resistance to acceleration, which can be determined by solving the equation F = ma where F is the force exerted on the body and m is its mass. The concept of mass is also sometimes confused with weight, which can be measured on a scale.
A physical object’s weight depends on the magnitude of gravitational force, which is different on every planet and even within a galaxy. This is because the Earth is an oblate spheroid rather than a perfect sphere, which means that objects at the North Pole experience more weight than those at the equator. However, the total mass of a person does not change regardless of the position on the Earth because that individual is still composed of the same atoms and particles.
What instrument is used to measure mass?
You can measure mass with many different instruments, but the one most commonly used in the laboratory is a balance. These are fairly expensive pieces of equipment and must be treated with great care. A simple balance has two scale pans – the unknown object is placed in one of these, and a standard object (such as a piece of fruit or iron) is placed on the other. The downward force of the standard object on the scale pan is counteracted by a downward force from the unknown object, and this gives the reading on the instrument.
Another way to measure mass is to use a spring scale, which compares the known reference mass with an unknown mass. These scales are less precise and will give different results when at a higher or lower altitude, as gravity affects the acceleration of the spring. A more sophisticated device, the SLAMMD, is used to determine the in-orbit mass of astronauts aboard the International Space Station. This rack-mounted apparatus uses Sir Isaac Newton’s Second Law of Motion, which states that force equals mass multiplied by acceleration.
What is the relationship between mass and weight?
People often use the words weight and mass interchangeably, but they are different measurements. An object’s weight depends on its location, while an object’s mass is a measurement of the matter it contains.
The SI base unit of mass is the kilogram, which was originally defined as the mass of one cubic centimeter of water at its melting point. However, because of the problems associated with using liquids, a solid prototype kilogram made from materials such as platinum-iridium allow is now used instead.
An object’s weight varies with its position on Earth because of the strength of gravity, but an object’s mass remains the same. You can measure an object’s weight with a balance, but you can also measure its mass by balancing it with another known amount of matter—such as a pineapple or a baseball bat. To weigh a pineapple, you might want to use a pan balance and to weigh a baseball bat, you might need a triple-beam or lever balance.
What is the relationship between mass and density?
While both mass and density are measurable quantities, they have very different properties. Mass implies the concentration of matter and is a measure of inertia, while density refers to the degree of compactness of matter.
A material’s density depends on the type of substance, but it can also vary with temperature. For example, air becomes denser when it cools.
In general, an object’s density increases as its volume increases. This is because there is less space between particles in a dense material than in a more empty one. The most common method for measuring an object’s mass is by placing it on a balance and reading its weight off of the scale. Unfortunately, this only works if the gravity and friction are the same on both sides of the balance. Fortunately, there are other ways to measure an object’s mass, such as using a density balance. In this case, the density of a substance is calculated by dividing its mass by its volume.