Difference Between Mass And Weight

Impression of a black hole, which has some of the strongest gravitational forces and mass in the universe.

The difference between mass and weight is that mass is the measurement of how much matter is contained within an object whereas weight is a measurement of how much gravity is pulling down on an object. Hence, on the moon, you will have the exact same mass as on Earth, but you will have a much lower weight due to the weaker gravitational pull from the moon compared to the Earth.

Science involves numerous different theories, laws, and concepts that work together to form a comprehensive view of the world around us and beyond. The scientific concept of things is used to classify and create a structure for scientists to work with.

For instance, when we look at something moving really fast, how do we define what fast is? For that, we use concepts like acceleration and velocity to turn “it is moving fast” into a tangible concept to measure and use. Velocity is defined as the rate of change of an object as it travels a certain distance within a certain time frame (miles per hour).

Before we get too much further let’s discuss what you came here for:

The difference between weight and mass is:

  • Mass is the measurement of how much matter an object contains
  • Weight is the measurement of how much pull gravity has on an object

Acceleration is defined as the change in velocity over time, usually as an increase in velocity. Many scientific concepts like velocity and acceleration have entered the mainstream language and it is important to understand their use in science so as to not misunderstand what they mean. There are many other concepts and terms being used in the mainstream that includes GMO (genetically modified organism) and organic. These terms and many others have specific meanings that can get misconstrued because of misuse by companies and people.

Two of the more popular concepts of science used in general society are weight and mass. When we weigh ourselves, we see either kilograms or pounds because we equate mass and weight outside of physics. Scientifically, they represent two related but different things.

Weight Vs. MassInteresting Facts
DependentUnlike mass, weight can be zero
DurabilityMass is indestructible and never changes
LocationWeight of an object changes depending on where it is located
Unit of MassTypucally kilograms or pounds
Unit of WeightNewtons
UniversalEverything in the universe has mass
VectorWeight is measured as a vector

Mass Vs Weight

The mass of an object is an intrinsic property of that object and represents the amount of matter that is in an object. Every object, big or small, has mass and that is usually represented with kilograms or grams as the standard unit of measurement. In physics, weight is the force on an object due to gravity. Weight is measured in newtons because of this.

When we weigh ourselves, we see what should be our mass instead of what our weight. Weight is defined as mass times the gravitational constant of Earth. The gravitational constant is essential the quantified strength of Earth’s gravity. Because the gravity of Earth does not change, we can measure our weight and mass almost anywhere on Earth.

Now, if we were to go to another planet or moon that had a different gravitational constant, then we would see some changes. If we go on the moon, which has weaker gravity than Earth, we would weigh less than on Earth. Our mass would stay the same because it is not affected by anything other than how much of us there is. If we were on Saturn, then we would weigh a lot more than on Earth because the gravity on Saturn is greater than Earth’s. Again, our mass would remain the same.

Saturn has a volume that is over 700 times larger than Earth’s and its gravity is immensely larger as well. Image from Universe today

In normal situations, the mass of an object is generally unchanged. This becomes complicated when we approach the speed of light. As we get closer to the speed of light, our relative mass increases. This occurs because of special relativity, an accepted and generally a confirmed theory of physics, states that the kinetic energy of an object’s motion at or near the speed of light is added to its mass, thus changing it.

One of the most interesting aspects of mass is that with enough mass you can generate a gravitational field and exert a gravitational force. While humans cannot do that, planets and other celestial bodies can. The mass of Earth is 5.972 × 10^24 kg, which is immensely large. This size allows it to exert a gravitational force on things like the moon, us, and anything with a much weaker gravity than its own. Our solar system is in a sort of balancing act with many different forces of gravity.

The Limits of Mass and Weight

Mass and Weight creates problems for creatures on Earth because there are limitations that we encounter and see in the world. In King Kong, we see giant monsters and creatures that tower over everything and move with ease and without worry. The largest creature on Earth is the blue whale and that is only because it is in the ocean.

If you take a gorilla and make it 20 times larger, it would collapse under its own weight and mass. The same will happen to a spider if you enlarge it until it is as large as a building. This occurs because the skeleton and muscles cannot support that much mass. The force acting on them is tremendous and there is no counterweight to support them at this size. Also, the energy demand is exceedingly large and they would burn out quickly.

The reason why the dinosaurs became so large was that they were similar to reptiles and needed less energy than mammals. The reason that the blue whale is the largest creature on Earth is that it lives in the water, which provides buoyancy to counter some of the force of gravity and prevents the collapse of its body.

The blue compared to humans and other aquatic life.

In terms of finding life on other planets, if there is life on planets with more gravity than Earth, then we would expect to see shorter and nothing as large as what is on Earth. Contrastingly, we would expect to see relatively taller lifeforms on habitable planets that have lower gravity than Earth.

If humans were to colonize other planets and moons, considering there are plans to create bases on the moon and Mars, we would also see changes in our weight but also our bodies. On the Moon, we would expect to see our bones become weaker and our muscles shrink because our mass is facing a weaker gravity and does not need the same amount of support from our muscles and skeleton. The same would happen on Mars because of its lower gravity.

It then becomes increasingly important to understand the consequences of these changes on individuals in areas of general human health and reproduction.

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