Why Have Objects Different Weights?

Atoms are the smallest particles of chemical elements and the basic building blocks of everything we see, touch, and smell.

Apart from the lightest atom, hydrogen, with only one proton in its nucleus (its centre) and one spinning electron, all the heavier atoms will contain varying amounts of protons, neutrons, and electrons.

A hydrogen atom is the simplest and lightest of all atoms.

Chemical elements like oxygen, iron, and gold are made of the same type of atoms and have the same number of protons in their nuclei. Their proton count determines their atomic number.

Therefore, every atom in a named element will have the same atomic number.

As we move up the periodic table, the atoms get heavier due to having more protons and neutrons in their nuclei.

Most of us will have held a piece of lead at some point. Yes, it feels heavy. Lead is a chemical element with the symbol Pb and the atomic number 82. The 82 protons and 126 neutrons in its nucleus give it its weight. Surrounding its nucleus are 82 electrons.

Electrons can be considered weightless.

The mass of an atom is the total number of protons and neutrons combined. To give you an idea of the size of an atom and how small they are, take a human being of, say, 70 kilogrammes in weight.

The total number of atoms making up that person's body is estimated to be 7 octillion, which is a staggering 7,000,000,000,000,000,000,000,000,000 atoms!

The most common atoms by mass that make up 99% of the human body are oxygen, carbon, and hydrogen.

When we die, all the elements that made us will dissipate over time and eventually become part of other objects or living things in the future.

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Every combination of atoms is a molecule, they can be simple or complex.

Here are two examples: A water molecule is composed of one oxygen atom and two hydrogen atoms, and a carbon dioxide molecule is composed of one carbon atom and two oxygen atoms.

Matter is a term used for anything that takes up space. It is all around us. Matter is the air you breathe, the shoes you wear, the water in your glass, and everything around you; it is what we are.

Anything that has mass is matter, and it comes in five known states: three commonly known as solid, liquid, and gas, the other two being plasma and Bose-Einstein condensates.

The difference in the structure of each state is described as the densities of the particles.

Mass is a combination of the total number of atoms, the density of the atoms, and the type of atoms in an object. Every object in the universe is made of matter, and the bigger the object, the more mass it has. Mass is measured in kilogrammes.

Objects with more mass are harder to move or stop than objects with less mass. The mass of an object can only change if you add or remove matter. You can place an object in different parts of the universe, but it will always have the same mass.

Weight is not the same as mass, as you will find out in the next paragraphs.

Weight is the result of the force of gravity acting upon an object, which can change if the force of gravity changes. I weigh 80 kilogrammes on Earth, but if I took the next flight to the Moon and weighed myself there, I would register at just over 13 kg.

The reason is that the Moon's gravity is much less than the Earth's, and therefore I am being pulled down on the weighing scales with less force than I would be on Earth.

On Mars, my weight would be just over 30 kg. If it were possible to stand on the sun (which I am not recommending), my weight would be over 2,165 kilogrammes, as the sun's gravity is almost 28 times stronger than the Earth's. If I were floating in outer space with no gravitational attraction from any objects, my weight would be zero.

Even the air we breathe has weight; one cubic metre weighs approximately 1.2 kg. On a windy day, you can feel the weight of the air acting on your face and body.

If you can imagine a column of air one-centimetre square sitting at sea level and going all the way up to space, then the weight of that air column would be classified as atmospheric pressure.

On Earth, that weight exerts a pressure of around 1 bar per square centimetre; however, you don't notice the weight because we are accustomed to it. If you were to climb to the top of Mount Everest, the air pressure there would be about one-third of what it is at sea level.

Density is a measure of mass per unit volume. An object made from a comparatively dense material, such as gold, will have less volume than an object that is not so dense, such as aluminium.

If you were to take one kilogram of gold and shape it into a ball, then do the same with one kilogram of aluminium, then the gold ball would be smaller in diameter than the aluminium ball of the same weight. I know that is a very simplistic explanation!

Objects with the most extreme densities in the universe are neutron stars and black holes.

Hopefully, the next few lines will provide a simple understanding of their density.

We are familiar with a scrap car or automobile being squeezed into a small block. The pressure in the crushing machine causes the car parts to move closer together, thus eliminating some of the space between them.

Now, an atom that is mostly "space" can also be compressed, but what is needed is a much greater force, that force being extreme gravity.

Now you will have to use your imagination.

As I said, a hydrogen atom is the simplest and lightest of all the different atoms; it contains just one proton in its nucleus and one spinning electron.

These few lines will give you a better idea of the amount of space in atoms.

Scale a hydrogen atom up to four kilometres in diameter; at that scale, the proton in its nucleus would be the size of a golf ball. The distance electrons are from the nucleus of an atom gives it its size, or edge, and determines how close atoms can be to each other.

Under extreme gravity, protons and electrons can combine and form neutrons; now the space where the electron was spinning around the nucleus has been eliminated, and without that space, the neutrons can lie side by side.

Regarding the scaled-up atom with a diameter of four kilometres. Can you imagine how many golf balls would be needed to fill that space?

Neutron star material, nicknamed neutronium, taking up an area the size of a sugar cube would weigh an incredible one billion tonnes here on Earth.

Imagine a star with roughly 1.5 times the mass of the Sun and compress it till it becomes a neutron star 15 kilometres in diameter. Now you can understand how dense neutron stars are; they are mostly made of neutrons, hence their name.

Black holes have the highest density of any known object, but we know little about what lies within them.

The end.

<><><>

You may find my easy-to-understand stories about the universe and life interesting and educational.

Subscribe to me for free, and you will see my latest stories. Enjoy.