What Matter Means in Physics

By 

Andrew Zimmerman Jones

Andrew Zimmerman Jones

Math and Physics Expert

• M.S., Mathematics Education, Indiana University
• B.A., Physics, Wabash College

Andrew Zimmerman Jones is a science writer, educator, and researcher. He is the co-author of "String Theory for Dummies."

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Updated on May 06, 2019

Matter has many definitions, but the most common is that it is any substance which has mass and occupies space. All physical objects are composed of matter, in the form of atoms, which are in turn composed of protons, neutrons, and electrons.

The idea that matter consisted of building blocks or particles originated with the Greek philosophers Democritus (470-380 BC) and Leucippus (490 BC).

Examples of Matter (and What Isn't Matter)

Matter is built from atoms. The most basic atom, the isotope of hydrogen known as protium, is a single proton. So, although subatomic particles aren't always considered forms of matter by some scientists, you could consider Protium to be the exception. Some people consider electrons and neutrons to also be forms of matter. Otherwise, any substance built of atoms consists of matter. Examples include:

• Atoms (hydrogen, helium, californium, uranium)
• Molecules (water, ozone, nitrogen gas, sucrose)
• Ions (Ca2+, SO42-)
• Polymers and Macromolecules (cellulose, chitin, proteins, DNA)
• Mixtures (oil and water, salt and sand, air)
• Complex Forms (a chair, a planet, a ball)

While protons, neutrons, and electrons are the building blocks of atoms, these particles are themselves based on fermions. Quarks and leptons typically aren't considered forms of matter, although they do fit certain definitions of the term. At most levels, it's simplest to state simply that matter consists of atoms.

Antimatter is still matter, although the particles annihilate ordinary matter when they contact each other. Antimatter exists naturally on Earth, although in extremely small quantities.

Then, there are things that either have no mass or at least have no rest mass. Things that are not matter include:

• Light
• Sound
• Heat
• Thoughts
• Dreams
• Emotions

Photons have no mass, so they are an example of something in physics that is not comprised of matter. They are also not considered "objects" in the traditional sense, as they cannot exist in a stationary state.

Phases of Matter

Matter can exist in various phases: solid, liquid, gas, or plasma. Most substances can transition between these phases based on the amount of heat the material absorbs (or loses). There are additional states or phases of matter, including Bose-Einstein condensates, fermionic condensates, and quark-gluon plasma.

Matter Versus Mass

Note that while matter has mass, and massive objects contain matter, the two terms are not exactly synonymous, at least in physics. Matter is not conserved, while mass is conserved in closed systems. According to the theory of special relativity, matter in a closed system may disappear. Mass, on the other hand, may never have been created nor destroyed, although it can be converted into energy. The sum of mass and energy remains constant in a closed system.

In physics, one way to distinguish between mass and matter is to define matter as a substance consisting of particles that exhibit rest mass. Even so, in physics and chemistry, matter exhibits wave-particle duality, so it has properties of both waves and particles.

Visible Light Spectrum

The visible light spectrum is the section of the electromagnetic radiation spectrum that is visible to the human eye. Essentially, that equates to the colors the human eye can see. It ranges in wavelength from approximately 400 nanometers (4 x 10 -7 m, which is violet) to 700 nm (7 x 10-7 m, which is red).1 It is also known as the optical spectrum of light or the spectrum of white light.

Wavelength and Color Spectrum Chart

The wavelength of light, which is related to frequency and energy, determines the color perceived by the human eye. The ranges of these different colors are listed in the table below. Some sources vary these ranges pretty drastically, and their boundaries are somewhat approximate, as they effectively blend into each other. Additionally, the edges of the visible light spectrum blend into the ultraviolet and infrared levels of radiation.

How White Light Is Split Into a Rainbow

Most light that we interact with is in the form of white light, which contains many or all of these wavelength ranges. Shining white light through a prism causes the wavelengths to bend at slightly different angles due to optical refraction. The resulting light is split across the visible color spectrum.

This is what causes a rainbow, with airborne water particles acting as the refractive medium. The order of wavelengths can be remembered by the mnemonic "Roy G Biv" for red, orange, yellow, green, blue, indigo (the blue/violet border), and violet. If you look closely at a rainbow or spectrum, you might notice that cyan also appears between green and blue. Most people cannot distinguish indigo from blue or violet, so many color charts omit it.

By using special sources, refractors, and filters, you can get a narrow band of about 10 nanometers in wavelength that is considered monochromatic light.2 Lasers are special because they are the most consistent source of narrowly monochromatic light that we can achieve. Colors consisting of a single wavelength are called spectral colors or pure colors.

Colors Beyond the Visible Spectrum

The human eye and brain can distinguish many more colors than those of the spectrum. For example, purple and magenta are the brain's way of bridging the gap between red and violet. Unsaturated colors such as pink and aqua are also distinguishable, as well as brown and tan.

However, some animals have a different visible range, often extending into the infrared range (wavelength greater than 700 nanometers) or ultraviolet (wavelength less than 380 nanometers).3 For example, bees can see ultraviolet light, which is used by flowers to attract pollinators. Birds can also see ultraviolet light and have markings that are visible under a black (ultraviolet) light. Among humans, there is variation between how far into red and violet the eye can see. Most animals that can see ultraviolet can't see infrared.

The Visible Light Spectrum
Color	Wavelength (nm)
Red	625 - 740
Orange	590 - 625
Yellow	565 - 590
Green	520 - 565
Cyan	500 - 520
Blue	435 - 500
Violet	380 - 435

 

What Is Time?

Time is familiar to everyone, yet it's hard to define and understand. Science, philosophy, religion, and the arts have different definitions of time, but the system of measuring it is relatively consistent.

Clocks are based on seconds, minutes, and hours. While the basis for these units has changed throughout history, they trace their roots back to ancient Sumeria (Sumer, an area that is now southern Iraq). The modern international unit of time, the second, is defined by the electronic transition of the cesium atom. But what, exactly, is time?

What is time, exactly? Physicists define time as the progression of events from the past to the present into the future. Basically, if a system is unchanging, it is timeless. Time can be considered to be the fourth dimension of reality, used to describe events in three-dimensional space. It is not something we can see, touch, or taste, but we can measure its passage.

Physics equations work equally well whether time is moving forward into the future (positive time) or backward into the past (negative time.) However, time in the natural world has one direction, called the arrow of time. The question of why time is irreversible is one of the biggest unresolved questions in science.

One explanation is that the natural world follows the laws of thermodynamics. The second law of thermodynamics states that within an isolated system, the entropy of the system remains constant or increases. If the universe is considered to be an isolated system, its entropy (degree of disorder) can never decrease. In other words, the universe cannot return to exactly the same state in which it was at an earlier point. Time cannot move backward.

Newton's first law of motion

 

Newton's first law of motion

What is Newton's first law of motion?

Newton's first law of motion states an object at rest or in motion will remain at rest or in motion unless acted upon by an unbalanced force. A ball will continue to move in the forward direction unless an unbalanced force acts on it.

What are the 3 laws of motion?

Newtons's first law of motion states an object at rest or in motion will remain at rest or in motion unless acted upon by an unbalanced force. Newton's second law of motion states the net force (F_{net}) of an object is dependent on both the mass (m) and acceleration (a) of an object. Newton's third law of motion states for every action, there is an equal and opposite reaction.

What are examples of Newton's 1st law of motion?

According to Newton's first law of motion; if a pan full of water was carried around a track, the water would tend to remain traveling forward. However, as the water moves to the left, the water will appear to splash to the right. Space is almost a perfect vacuum void of matter and gravity. Consider a satellite orbiting Earth at 17,500 mph. If a rock were released from the satellite, the rock would orbit earth at a velocity of 17,500 mph next to the satellite.

In 1687 English scientist Sir Isaac Newton published his three laws of motion. Newton's laws of motion are relatively simple statements that revolutionized humanity's understanding of the physical world. Today they are considered foundational to classical mechanics, one of the main branches of physics.

A simple definition of Newton's first law of motion is that it is a law of physics that states that an object at rest or in motion will remain at rest or in motion unless acted upon by an unbalanced force. A force is a push or pull on an object with mass that causes a change in the object's motion. Force is measured in Newtons (N) or kg m/s^{2}.

Balanced Force

The image below shows forces directly acting on the box. Since the magnitude of the arrows are equal, the upward and downward forces are balanced. Balanced forces are equal in magnitude and opposite direction. According to Newton's first law, balanced forces are responsible for keeping an object at rest or maintaining an object's constant velocity.

Inertia is directly proportional to mass. The greater the mass an object has the more the object will resist a change in motion. The elephants in this image have different masses. If these elephants were running at the same speed and had to stop immediately, the more massive elephants would resist changes to their forward state of motion more than the less massive elephants. Thus, according to Newton's first law of motion, the more massive elephants are said to have greater inertia.

Law of Conservation of Matter

 

Law of Conservation of Matter

What is conservation of mass?

The law of conservation of mass states that, during processes like chemical reactions, matter can neither be created nor destroyed.

What is an example of conservation of matter?

A common example of the law of conservation of matter is the reaction of baking soda and vinegar. At first glance, the reaction seems to finish with less mass than it started with. But by placing a balloon atop the reaction container, one can see that the lost mass is actually due to the creation of a gas called carbon dioxide.

What does the law of conservation of matter state?

The law of conservation of matter states that no matter can ever be created or destroyed. Chemical reactions simply rearrange atoms to form new compounds.

he law of conservation of matter, also know as "the law of conservation of mass," states that matter can neither be created nor destroyed. The law's modern form stems from Antoine Lavoisier's work with chemical reactions in the late 18th century. It replaced the phlogiston theory, which stated that mass was destroyed during combustion processes.

Lavoisier's new theory, along with the work of countless other scientists, helped lay the groundwork for the discovery of the chemical elements and, eventually, the periodic table. It has now been so thoroughly tested and is so universally accepted, that it is considered a scientific law.

Matter is defined as physical material that occupies space and possesses mass. The phlogiston theory, which had a very long history, was built upon the observation that fuel loses mass as it burns. This is a correct observation: after you burn a piece of wood, the wood has less mass than it did prior to burning. But the phlogiston theory did not take into account the escape of gases. Burning wood releases carbon dioxide, water vapor, and aerosols. The weighing of these gases was impossible until the invention of the vacuum pump in the 17th century. This invention allowed scientists to weigh gases and to eventually prove that mass was not destroyed during combustion processes. Rather, the mass is simply transformed into gases.

This conclusion is essentially true with all chemical reactions. In all cases, atoms are not created or destroyed; they are simply broken apart, rearranged, or put together in new ways. Of course, these new resulting combinations of atoms can form very new, very different substances. But the mass of the atoms before the reaction and the mass of the atoms after the reaction are always equal.

Modern exceptions to this law have been made to allow for nuclear processes, including fusion, fission, and matter-antimatter reactions. In these cases, mass can be converted into energy and vice versa. 

For chemists, the implications of this law are many. First, the law allowed for chemical reactions to be fully understood and fully quantified. Previously ignored chemical substances (like carbon dioxide being released from a fire) were studied and measured.

The law also allows scientists to predict the mass of the products in a chemical reaction. This can be vital in a variety of situations. Rocket fuel, for example, is specifically formulated with the right ratio of kerosene and liquid oxygen so that it burns fully and completely. Knowing the mass of the two products being burned allows scientists to predict exactly how carbon dioxide and water vapor will be produced. From there, scientists can estimate the mass and velocity of the exhaust gases and predict the amount of thrust that a rocket engine will provide.

The Difference Between Travel and Tourism

 The Difference Between Travel and Tourism

What is the difference between travel and tourism? In short, travel describes a broad activity, and tourism is part of it. This doesn’t mean they are the same, because not all travel is tourism. 

According to Merriam-Webster, tourism describes the practice of traveling for recreation and the guidance or management of tourists. People in a place that is traveled to will set up businesses like hotels, tour companies, and more, to support visitors, creating a tourism industry.

The term travel means “to go on a trip or a tour.” This could include traveling for tourism, but it could also include business travel, travel to visit family, travel for immigration, and other reasons. There are plenty of reasons to travel that don’t involve tourism.  

The difference between travel and tourism is subtle, but it’s there! And it’s important to note it before we unpack the differences between travelers and tourists.

Tourist vs. Traveler: What’s the Difference?

It’s hard to unpack the differences between tourists and travelers because there’s both a perceived definition of these words (this is what we see talked about online) and there’s the formal, dictionary definition. 

Perceived Differences Between Tourist and Traveler

These words are often used to evoke two specific images of a person who travels. The “traveler” is portrayed as someone who is intrepid and goes to less mainstream places. Whereas a “tourist” is wandering around with a guidebook in their hands, going to well-known sights. 

This creates a binary where a “tourist” is one thing, different from a “traveler.”

I don’t think these descriptions are totally fair. There is much more nuance involved, because a tourist can be a mixture of these descriptions, and, participating in “tourist” activities isn’t always a bad thing. 

Official Definitions of Tourist and Traveler

I’ve listed the common perceived ideas around tourist vs. traveler. But what are the official definitions? 

Merriam Webster dictionary defines a tourist as “one that makes a tour for pleasure or culture,” and a traveler as “one that goes on a trip or journey.” 

According to the Oxford English Dictionary, a tourist is “a person who travels for pleasure,” and a traveler is “a person who is traveling or who often travels.”

By these definitions, there really isn’t much of a distinction between the two. Both words refer to the act of traveling to another location. The main distinction between them is that the definition of “tourist” includes the “why” behind that traveling: for pleasure or for culture. 

That distinction (the “why”) is noted in the definition for tourist, but that doesn’t mean it can’t apply to the traveler as well. Anyone who goes on a trip or journey is going to have a “why” – they are heading out on a trip for pleasure, or for culture, or for both.

So, is there a difference between travel and tourism? Yes, but the difference is subtle. Tourism is a part of travel, but not all travel participates in tourism. Given this, you can definitely argue that “traveler” describes people traveling for a variety of reasons, from business travel to immigration. Whereas a tourist is traveling specifically for the experience of tourism, and leisure. 

The way that the tourist vs. traveler binary is used by some to suggest that some tourists do travel better than others isn’t really accurate. It’s okay to be a tourist. When you look at the pros and cons of tourism, simply being a tourist does contribute toward a positive impact when we travel.

That said, a lot of the perceptions of what a “traveler” is point to responsible travel practices that we should all be learning about and trying our best to do. 

The tourist vs. traveler binary contributes to a superiority complex that seems rooted in a sense of competition. And that competition is focused on an individual’s personal “travel identity.”

Rather than focusing on being a traveler vs. a tourist, I think we can all shift our focus instead on putting conscious effort toward promoting and participating in responsible tourism. 

Traveling in a way that leads to more engagement with local life is absolutely something we all should be talking about, learning about and practicing. But let’s do it so that our travel has a better impact on the world – Not so that we can claim we’re one type of traveler over another. 

 

Tourist VS Traveller