Generally, we use the terms ‘mass’ and ‘weight’ interchangeably. However, in reality, they are two different things. We need to get a little scientific to explain this, but mass and weight are two different things. In fact, the mass of an object is always the same, but the weight changes depending on where that object is.
Read on to find out more about the differences between mass and weight.
What is mass?
In short, mass is the measure of what something is composed of. Take the human body, for example. We jump on the scales to find out our weight, right? Well, not technically. What those scales are actually measuring is your mass.
Mass is also the measure of how much force is required to change something’s path. You might remember this from high school, the equation of F (force) = M (mass) x A (acceleration).
What is weight?
We’ve determined that what most people refer to as ‘weight’, is actually ‘mass’. So, what exactly is weight? In technical terms, weight measures the downward force that gravity exerts on an object. Weight is also not measured in kilograms, but rather in Newtons
Is there really a difference in most practical applications?
Scientifically, yes, there is always a difference between mass and weight. By knowing an object’s mass, we can determine its weight because the force of gravity on earth is always the same. However, for that same reason, we don’t need to worry too much about the difference because we’re on Earth, where gravity remains the same.
So, as long as you remain on planet Earth, you don’t really need to start referring to the weight of something in Newtons, because it would just be confusing to everybody except scientists.
Do scales measure weight or mass?
Technically, they do both. Scales are made with a load cell, and they measure the amount of force exerted on that cell. Then, they use gravity to give you the object’s mass. However, in most common applications, we refer to this as the object’s weight.
In modern industries, for example, there are several types of weighing equipment. Bench scales, load cells, crane scales and many more. Essentially, all of them give us the weight of an object, or at least what we refer to as weight. They actually give us the mass of an object, but since we’re not blasting those objects into space, we can comfortably refer to it as weight.
Why is it important to know the difference?
The key difference between the two is that an object’s mass remains the same no matter where it goes. However, the object’s weight changes depending on the force of gravity. Even extreme altitude can affect weight, so there may be some instances where an object’s weight can change. In common terms, we can safely use the words ‘mass’ and ‘weight’ interchangeably. But in industries like astronomy, physics, chemistry and aerospace, miscalculations between mass and weight can have significant consequences.