Matter

context: Before the 20th century, the term matter included ordinary matter composed of atoms and excluded other energy phenomena such as light or sound. This concept of matter may be generalized from atoms to include any objects having mass even when at rest, but this is ill-defined because an object's mass can arise from its (possibly massless) constituents' motion and interaction energies. Thus, matter does not have a universal definition, nor is it a fundamental concept in physics today. Matter is also used loosely as a general term for the substance that makes up all observable physical objects.
qas: answers: text: 20th
question: In what century was the term matter defined excluding energy phenomena like light and sound?

answers: text: matter
question: What term is used for the substance that composes all observable physical objects?

answers: text: interaction energies
question: The mass of an object can come from the motion of its constituents or what other source?

answers: text: universal
question: What term is used to describe the type of definition that matter would have if all scientists could agree on its definition?

answers: text: at rest
question: Prior to the 20th century, the definition of matter included any object that had mass even when it was in what state? 

context: All the objects from everyday life that we can bump into, touch or squeeze are composed of atoms. This atomic matter is in turn made up of interacting subatomic particles—usually a nucleus of protons and neutrons, and a cloud of orbiting electrons. Typically, science considers these composite particles matter because they have both rest mass and volume. By contrast, massless particles, such as photons, are not considered matter, because they have neither rest mass nor volume. However, not all particles with rest mass have a classical volume, since fundamental particles such as quarks and leptons (sometimes equated with matter) are considered "point particles" with no effective size or volume. Nevertheless, quarks and leptons together make up "ordinary matter", and their interactions contribute to the effective volume of the composite particles that make up ordinary matter.
qas: answers: text: atoms
question: What kind of particles make up every object in the world that can be touched?

answers: text: subatomic
question: The smaller particles that make up atoms, like protons and neutrons, are what kind of particles?

answers: text: photons
question: What subatomic particle has no volume or rest mass?

answers: text: point particles
question: What  kind of particles are quarks and leptons?

answers: text: volume
question: Despite not having size or volume themselves, quarks and leptons contribute to what measure of composite particles in matter?

context: Matter commonly exists in four states (or phases): solid, liquid and gas, and plasma. However, advances in experimental techniques have revealed other previously theoretical phases, such as Bose–Einstein condensates and fermionic condensates. A focus on an elementary-particle view of matter also leads to new phases of matter, such as the quark–gluon plasma. For much of the history of the natural sciences people have contemplated the exact nature of matter. The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, was first put forward by the Greek philosophers Leucippus (~490 BC) and Democritus (~470–380 BC).
qas: answers: text: four
question: How many phases of matter are there?

answers: text: quark–gluon plasma
question: What new phase of matter can be considered with a focus on elementary particles?

answers: text: particulate theory of matter
question: What is the theory that matter is made up of discrete building blocks called?

answers: text: Leucippus
question: What colleague of Democritus, also a Greek philosopher, helped him propose the particulate theory of matter?

answers: text: natural sciences
question: People have been wondering about the nature of matter for the entire history of what branch of science?

context: Matter should not be confused with mass, as the two are not quite the same in modern physics. For example, mass is a conserved quantity, which means that its value is unchanging through time, within closed systems. However, matter is not conserved in such systems, although this is not obvious in ordinary conditions on Earth, where matter is approximately conserved. Still, special relativity shows that matter may disappear by conversion into energy, even inside closed systems, and it can also be created from energy, within such systems. However, because mass (like energy) can neither be created nor destroyed, the quantity of mass and the quantity of energy remain the same during a transformation of matter (which represents a certain amount of energy) into non-material (i.e., non-matter) energy. This is also true in the reverse transformation of energy into matter.
qas: answers: text: mass
question: What similar term is often used interchangeably with matter, although the two differ slightly in modern physics?

answers: text: closed
question: Being a conserved quantity means that the value of mass doesn't ever change as long as it's in what kind of system?

answers: text: energy
question: Special relativity says matter can disappear by conversion into what state?

answers: text: Earth
question: What planet isn't a closed system but sometimes appears to be because of the approximate conservation of matter?

context: Different fields of science use the term matter in different, and sometimes incompatible, ways. Some of these ways are based on loose historical meanings, from a time when there was no reason to distinguish mass and matter. As such, there is no single universally agreed scientific meaning of the word "matter". Scientifically, the term "mass" is well-defined, but "matter" is not. Sometimes in the field of physics "matter" is simply equated with particles that exhibit rest mass (i.e., that cannot travel at the speed of light), such as quarks and leptons. However, in both physics and chemistry, matter exhibits both wave-like and particle-like properties, the so-called wave–particle duality.
qas: answers: text: matter
question: What term does science not have a universally-accepted scientific definition for?

answers: text: mass
question: Sometimes scientific terms were historically considered in ways we know now aren't compatible because scientists didn't need to distinguish matter from what other term?

answers: text: matter
question: What word do physicists sometimes consider to be defined as particles exhibiting rest mass?

answers: text: wave–particle duality
question: What duality describes the conflicting properties of matter in the fields of chemistry and physics?

answers: text: the speed of light
question: Quarks and leptons are sometimes considered matter because they can't travel at what speed?