Kids are inquisitive, and teaching them about the concept of mass can set them up for more advanced concepts in subjects like maths and physics later on. Mass is the amount of matter contained within an object, independent of its location or arrangement.
It can be measured with a balance, which is often used in schools and labs. This type of balance works in space and in places with different gravity, too.
What is Mass?
In physics, mass is the amount of matter contained in an object. It is also referred to as an object’s inertia or resistance to acceleration (change of velocity). An object’s mass determines its gravitational attraction to other objects.
A pebble has less mass than a boulder. It is therefore easier to move the pebble, despite having the same amount of matter. The more matter an object contains, the greater its mass.
Another important property of mass is that it is conserved, even in the case of chemical and physical changes to an object or system. This is why astronauts in space appear to be weightless, despite their gravity-induced downward acceleration on Earth. This is also the basis of Einstein’s Mass-Energy Equivalence: m=E/c2.
How is Mass Measured?
Mass is measured using a balance. A known amount of matter is placed on one side of the balance while a mystery object is weighed on the other side. When the unknown object is the same density as the known item, it will have the same weight on both sides of the balance.
However, when the unknown object has a different density from the known item, it will have an upward force on the scale and an unknown value for its weight. This can be corrected for by comparing the objects to a stainless steel standard that is calibrated to conventional mass.
Mass is the intrinsic value of a body that can be used to determine various other properties such as its gravitational attraction to other bodies, resistance to acceleration due to a force, and inertia. It can also be used to derive energy content of a sample through the theory of Relativity as described by Albert Einstein’s E = mc2. The unit of measurement for mass is called the kilogram and was originally defined as one cubic decimeter of water at freezing temperature.
What is the Relationship Between Mass and Weight?
Mass and weight are closely related, but they measure different things. While mass measures the amount of matter in an object, weight is the force exerted by gravity on that matter. This force depends on both the object’s mass and the strength of the gravitational field where it is located. Thus, an object’s weight will be different on Mars or Saturn than it is on Earth.
Most modern weighing scales use strain gauge load cells to measure mass, but older models often have beams that balance one side of the object against the other. Both of these methods measure the acceleration due to gravity (also called weight), but the accuracy of these measurements varies. A high-quality scale can measure the mass of an object to within a few grams. For more precise measurements, researchers can use special laboratory instruments that have more advanced features such as frequency shift technology. These instruments measure an object’s mass to a resolution of one part in 2,000.
What is the Relationship Between Mass and Density?
It’s important to understand the difference between mass and density. Mass is a measure of the amount of matter an object contains, while density is a measurement of how compactly that matter is packed into a given volume.
Volume is the amount of space a substance takes up, and it can be measured in units like cubic centimeters (cm3) or liters (L). Mass and volume are related because, as you might have learned from Boyle’s Law, Gay-Lussac’s Law, and Charles’s Law, increasing the temperature, pressure, or volume of a sample will increase its mass, while decreasing the temperature, pressure, or volume will decrease its mass.
Density is the ratio between an object’s mass and its volume, so it provides information about how tightly a material’s particles are packed together. The SI unit for density is kilograms per cubic meter, though it’s also commonly expressed in g/cm3, g/mL, and g/L. This is because, while mass can only be measured directly, density can be calculated from mass and volume using the equation r = m / V.