Mass and weight are two measurements that often get confused. The amount of matter that something has is its mass, but its weight changes depending on the gravitational force acting on it.
The most common way to measure mass is with a balance. Let’s explore some other methods of determining an object’s mass.
What is Mass?
Most students are taught to weigh things using a balance. That is a great way to introduce the concepts of weight and mass, but it doesn’t teach the real definition of each term.
Mass is a property of matter, regardless of its location in the universe. It is a fundamental quantity with the SI unit of kilogram (kg).
Weight is a force that depends on gravitational attraction. Two objects of the same size can have different weights because gravity affects them differently. An object’s weight can change, for example, when it is moved to a different planet with a stronger or weaker gravity. However, the object’s mass will stay the same. Many people get the two terms confused and use them interchangeably, but they are different measurements.
Gravitational Force
The gravitational force that exists between objects with mass attracts them and causes them to fall toward each other. This is a universal law of nature that was first postulated by Sir Isaac Newton in 1687. Gravity is inversely proportional to the square of the distance between the centers of the two masses and increases with the mass of the objects.
In technical contexts, engineers use the term kilogram-force to describe the standard value of gravity (symbol: G) at Earth’s surface—9.80665 m/s2—and they convert mass to a corresponding unit of force in newtons. Objects weigh differently on different planets, depending on their size and the strength of their gravity, but they always have the same mass.
Ever since the 17th century, scientists have tried to measure the strength of gravity in a laboratory. The most precise technique uses a torsion balance. Students can experiment with this equipment and record the results on graph paper. They can also write an equation from the data to show the relationship between the force of gravity and the mass of the object.
Weighing Scales
A scale is the instrument used to measure the amount of matter in an object. It can be used in a variety of applications, from measuring a person’s body weight to weighing ingredients for baking. Weighing scales are also commonly found in chemistry labs and other scientific settings.
The most common scales used in mass measurement are balances, which compare unknown masses to a known quantity – in this case standard weights. This allows the scale to provide a reading that is independent of changes in gravity. In modern weighing scales, load cells convert the downward force into a proportional electrical signal that can then be converted and displayed to show weight on an indicating element.
When weighing samples in a laboratory, it’s important to remove the added weight of the container, as this can bias the results. This process is called taring, and it can be accomplished by pressing a tare button on the instrument.
Lab Equipment
Measurements of mass are vital for numerous scientific disciplines, including chemistry. The most common method of measuring mass is with a balance, which utilizes an object’s gravitational acceleration to determine its weight. A precise balance is necessary to ensure that all of your measurements are accurate.
For liquid measurements, lab tools like graduated cylinders, pipettes, and burettes provide precise measurements that are vital for accurate chemical reactions. These instruments are engineered with precision in mind, enabling scientists to achieve incredibly small quantities without error.
Other important lab equipment includes a variety of glassware, weighing scales, and heat sources like Bunsen burners and hot plates. Proper storage and organization of all laboratory apparatus helps to ensure that it is safe for use. It also facilitates easy retrieval, reducing time spent searching for the right equipment for an experiment. The right lab apparatus can make or break an experiment, so it is important to carefully assess your needs and select the correct equipment.