Most commonly, mass is measured using a balance. An unknown object is compared to a known value of mass to obtain the value of the unknown. The balance works even in space or places where the force of gravity is different.
Kids are inquisitive, so it’s important to teach them about physics at an early age. Introducing them to concepts like weight and mass at this time will help them effortlessly grasp more advanced concepts later on.
Weight
Although many people use the words “weight” and “mass” interchangeably, they are two distinct physical properties. Mass is a measure of how much matter an object contains, while weight is a measurement of the force of gravity acting on an object.
In the metric system, mass is measured in kilograms and related units. In the customary (English) system, it is measured in ounces and pounds. A physical prototype kilogram was created in 1875 to standardize the unit across countries and systems.
Weighing objects is the simplest way to determine their mass, but this method only works in no-gravity, frictionless environments. A better approach is to look at how an object flies through space or moves on the Earth’s surface, where gravity and friction are present.
Density
Density is the measure of mass per unit volume. It is a physical property, determined by the mass and composition of a substance and can be measured without changing its chemical makeup.
It is one of the most important properties for distinguishing pure substances from mixtures. It is also an important factor for identifying the concentration of binary solutions, such as sugar-water or alcohol-water solutions.
In a laboratory setting, density measurement is typically done with a graduated cylinder and an accurate scale or balance. Using an object of known mass, students can calculate the density by dividing its mass by its volume. Students can then compare the results to those of other materials, including liquids and gases. Density is a crucial concept in physics and has many practical applications such as determining which objects float or sink, or whether a liquid can withstand certain pressures. For this reason, it is vital that students learn how to accurately and reliably measure density.
Volume
The volume of an object is the amount of three-dimensional space it occupyes. It is calculated by multiplying length, width and height. Volume is commonly measured in cubic units, such as liters, cubic centimeters and cubic millimeters. One liter is equal to 1000 cubic centimeters or 1 dm3.
Since length and height are linear measurements, they are derived from units of length. The SI base unit for the kind of quantity mass is kilogram (kg). Other important SI units include meter (kind of quantity: length, symbol m), second (kind of quantity: time, symbol s) and mole (kind of quantity: amount of substance, symbol mol).
It is very important to understand the difference between weight and mass. While weight is influenced by gravity, mass is the inertia of an object. For example, you may weigh much less on the Moon than you do on Earth, but you will still have the same mass. Mass is also important in quantitative chemistry, where a reaction is stoichiometric when the quantities of the reacting substances are equal.
Gravity
Gravity plays a big role in mass measurement. It is the force that attracts all matter, including people, to the Earth and other planets. It also steers the orbital paths of celestial bodies such as stars, planets and moons.
It is difficult to measure directly because it requires comparing the acceleration of two objects that have identical masses. However, physicists have developed several techniques for measuring gravity on short distance scales. Many of these use modern ideas from quantum physics. For example, some experiments involve lasers that cause clouds of ultracold atoms to act like waves, canceling out some and strengthening others. These waves can be measured to reveal the magnitude of the gravitational force.
Unlike the other four fundamental forces of physics, G has not been observed to vary from place to place in the universe. This could be due to the fact that other cosmic phenomena such as radio waves or electromagnetic radiation might interfere with our ability to detect gravity.