Matter: Definition & the Five States of Matter
Matter is defined as anything that has mass and takes up space (it has volume). What is It's all about the physical state and energy in the atoms and molecules. Kids learn about the science of heat and temperature including conduction, transferring of heat, expansion, and the states of matter. The energy that drives much. Law of Conservation of Energy and Mass for Kids - Interesting videos, lessons, quiz games, diagrams, presentations and activities on laws of conservation.
The monkey, holding the free end of the vine, climbs up the central tree. It then moves several treetops away, maintaining the same altitude. Finally, the monkey grasps the vine that is still tied to the central tree and swings down, past the central tree, and up again until it lands in a third tree. An observer watching the monkey swinging from one tree to the other will conclude that the system possesses energy and can do work.
The necessary elements in this system are the monkey, the trees, Earth, and the vine. The monkey provides the initial energy by climbing the trees, while the trees support the monkey against the force of gravity, which pulls downward. The vine supports the monkey so that it remains free to then swing upward against the force of gravity and into another tree.
When all these elements occur together, the system is capable of doing work; it has energy. As the monkey swings on the vine, it is acting like a pendulum. Like any pendulum, it is exhibiting the difference between two kinds of energy—kinetic energy and potential energy. Kinetic energy is the energy of motion. While the monkey is swinging from one tree to the other, it has kinetic energy. So too does a speeding bus, a falling raindrop, and a spinning top.
Any moving object has this type of energy. Potential energy is the energy an object or system has because of the position of its parts. For example, a stretched spring has potential energy. Force has been applied to stretch the spring, creating stored energy. The more the spring is stretched from its normal position, the greater its capacity to do work when released.
Likewise, a steel ball has more potential energy raised above the ground than it has after falling to Earth. In the raised position it is capable of doing more work, because of the pull of gravity.
The monkey also has potential energy as it stands in the treetop. The monkey is not moving, so it has no kinetic energy. The work done to lift the monkey against the force of gravity has created potential energy.
The potential energy is released when the monkey jumps off the tree. Gravity pulls it downward, and it travels faster and faster until, as it sweeps by the ground, it is traveling very fast. In place of the lost potential energy, the system has gained more and more kinetic energy. When the monkey lands in the next tree, the system again has potential energy but no kinetic energy. This example demonstrates a basic property of energy—one form of energy can be changed into another.
In this case, potential energy was converted to kinetic energy, which was then changed back into potential energy. Mechanical energy is equal to kinetic energy plus potential energy. It is thus all the energy an object has because of its motion and its position.
Machines—from simple tools such as wedges, levers, and pulleys to complex devices such as automobiles—use mechanical energy to do work. A hammer uses mechanical energy to drive a nail into a board. When raised above the nail, the hammer has potential energy from the work done in lifting it. When the hammer is moved toward the nail, the potential energy becomes kinetic energy, which can do the work of driving the nail. Contact between the hammer and the nail transfers energy to the nail and then to the board.
Forms of Energy The many forms of energy include chemical, nuclear, electrical, radiant, and heat energy.
What is the relationship between matter and energy?
All these types of energy can do work. Each of these forms can be described as either of the two basic energy forms: An explosion can do work against the force of gravity, for example, by throwing pieces of material into the air. A mixture of chemicals that can do work is said to have chemical energy. But not all chemical systems that can do work are as dramatically energetic as gunpowder or dynamite.
Chemical energy is stored in the bonds of chemical compounds and may be released during a chemical reaction, when the compounds are changed. To understand chemical energy it is necessary to study what happens during a chemical reaction. All matter is made up of tiny units called atoms. An atom can bond to other atoms to form a group called a molecule. Atoms and molecules are the basic building blocks of matter—such as rocks, wood, air, soil, water, and living things.
Chemical energy is what holds the atoms in a molecule together. For example, one kind of atom is the oxygen atom O. An oxygen atom and two hydrogen atoms H2 combine to form a water molecule H2O. One kind of sand molecule—silicon dioxide SiO2 —contains one atom of silicon Si and two atoms of oxygen. Molecules are formed in chemical reactions. Some molecules give off a great deal of energy when they are formed. Such molecules are very stable because all that energy must be put back into them before they break apart.
Other molecules release very little energy when they are formed. Such molecules are very unstable.
They react easily to form more stable molecules. During these reactions much energy is given off. Nitroglycerin—a dense, oily liquid—changes readily to water, carbon dioxide, nitrogen, and oxygen. This reaction is explosive because it occurs very rapidly and because the suddenly formed gases take up much more room than did the liquid nitroglycerin.
Other chemical reactions can produce energy but not be explosive. They may occur more slowly, and the resulting molecules may take up the same amount of room as the original molecules. Food energy is a form of chemical energy. Plants absorb energy from sunlight and store it in energy-rich chemicals, such as glucose. This process is called photosynthesis. Animals that eat plants use the chemicals created by photosynthesis to maintain life processes.
Other animals may eat plant-eating animals to gain the energy-rich chemicals that the plant-eaters formed from the chemicals of plants. Since food energy is what keeps living things moving, it is clearly able to do work. The nucleus is composed of two kinds of particles—protons, which have a positive charge, and neutrons, which have no charge. The nucleus is surrounded by a cloud of electrons, which are negatively charged.
Electric forces bind the electrons to the nucleus. Nuclear energy is a form of potential energy, because the nuclear particles can store energy. Some nuclei spontaneously rearrange, losing some particles and emitting energy. This process is called radioactivity.
For example, a nucleus of the element radium can spontaneously eject a cluster of two neutrons and two protons called an alpha particle and a gamma ray a type of electromagnetic radiation. These carry away energy from the nucleus, which changes into a smaller, more stable form. Nuclear reactions fuel the Sun and other stars.
Quarked! . How are matter and energy related?
People use nuclear energy in nuclear power plants that produce electricity and in nuclear weapons. Nuclear energy also powers some vehicles, such as nuclear submarines. Two techniques exist that allow people to release nuclear energy through nuclear reactions.
The first, called fission, involves splitting a nucleus into two fragments.
The second involves combining two nuclei to form one nucleus. This technique is called fusion.
Matter: Definition & the Five States of Matter
Both techniques have been used to make bombs, but only fission has been used successfully in power plants and vehicles. Fission makes use of elements with very heavy atoms, such as uranium.
A large amount of energy is required to hold together the nucleus of such a heavy atom. In fact, more energy is required to hold together the uranium nucleus than to hold together two nuclei that are half the size of a uranium nucleus.
In atomic bombs and in fission reactors at nuclear power plants, uranium atoms are bombarded with particles, such as free neutrons. When a neutron hits a nucleus, the nucleus splits into two smaller nuclei, releasing a great deal of energy. In the reaction, called a chain reaction, some of the neutrons of the uranium nucleus fly off and hit other nuclei.
These collisions in turn cause the other nuclei to split apart and to release more energy and more neutrons. The process can continue explosively, as it does in an atomic bomb.
In nuclear reactors the fission must be controlled. Typically, metal rods are inserted to capture some of the neutrons and slow down the reaction.
The second kind of nuclear reaction is harder to produce and control. It makes use of the fact that very small nuclei, such as those of hydrogen and its isotopesrequire slightly more energy per proton and neutron to exist than do somewhat heavier nuclei. The situation is exactly opposite to that of the uranium nucleus, where the lighter nuclei require less energy. If two hydrogen nuclei can be combined to form one heavier nucleus, a large amount of energy is released. This type of reaction occurs in the Sun.
By a somewhat complicated series of reactions, four hydrogen nuclei join together to form a new helium nucleus, giving off a great deal of energy in the process. This joining of nuclei is the source of all the energy emitted by the Sun. Temperatures in this kind of reaction must be very high in the millions of degrees before the nuclei can collide with the force needed for them to join together.
The reaction is called a thermonuclear fusion reaction. A thermonuclear fusion reaction occurs when a hydrogen bomb explodes. Scientists are trying to develop a way of releasing energy by fusion reactions under controlled conditions, in order to produce electrical power.
Fusion reactions release far more energy than fission reactions do. See also nuclear energy ; plasma and plasma physics.
Electric currents turn motors and drive machinery. Electric currents provide the energy of laborsaving appliances such as power tools, vacuum cleaners, and dishwashers. Clearly, the currents can do work and thus possess energy. An electric current is a stream of moving particles or atoms that carry an electrical charge.
Most liquids contract as they freeze. One of the important characteristics of water is that it expands when it freezes, so ice floats. The freezing point is often nearly the same temperature as the melting point, but is not considered to be characteristic of a substance, as several factors can alter it. For example, adding dissolved substances, or solutes, to a liquid will depress the freezing point. An example of this is using salt slurry to lower the temperature at which water freezes on our roads.
Other liquids can be cooled to temperatures well below their melting point before they begin to solidify. Sublimation When a solid is converted directly into a gas without going through a liquid phase, the process is known as sublimation.
Sublimation occurs when kinetic energy of the particles is greater than atmospheric pressure surrounding the sample. This may occur when the temperature of the sample is rapidly increased beyond the boiling point flash vaporization. More commonly, a substance can be "freeze dried" by cooling it under vacuum conditions so that the water in the substance undergoes sublimation and is removed from the sample.
A few volatile substances will undergo sublimation at normal temperature and pressure. Vaporization can occur through either evaporation or boiling. Because the particles of a liquid are in constant motion they frequently collide with each other, transferring energy when they do so. This energy transference has little net effect beneath the surface, but when enough energy is transferred to a particle near the surface; it may gain enough energy to be knocked completely away from the sample as a free gas particle.
This process is called evaporation and it continues as long as liquid remains. It is interesting to note that a liquid cools as it evaporates. The energy transferred to surface molecules, which causes their escape, is carried away from the remaining liquid sample. When enough heat is added to a liquid that vapor bubbles form below the surface of the liquid, we say that the liquid is boiling. The temperature at which a liquid boils is variable.
Boiling point is dependent upon the pressure the substance is under. A liquid under higher pressure will require more heat before vapor bubbles can form within it. At high altitudes, there is less atmospheric pressure pressing down on the liquid, so it will boil at a lower temperature. The same amount of liquid at sea level is under a greater atmospheric pressure and will boil at a higher temperature. Condensation and deposition Condensation is when a gas transforms into a liquid.
Condensation occurs when a gas has been cooled or compressed to the point where kinetic energy of the particles can no longer overcome the intermolecular forces. An initial cluster of particles initiates the process which tends to further cool the gas so that condensation continues. When the gas transforms directly into a solid, without going through the liquid phase, it is called deposition or desublimation.
An example of this occurs when subfreezing temperatures convert water vapor in the atmosphere into frost or ice. Frost tends to outline solid blades of grass and twigs because the air touching these solids cools faster than air that is not touching a solid surface.
Changing States of Matter What is a physical change in matter? Molecules can move from one physical state to another phase change and not change their atomic structure. Oxygen O2 gas has the same chemical properties as liquid oxygen.
The liquid state is colder and denser less energybut the molecules are the same. Water H2O is another example. A water molecule is made up of two hydrogen H atoms and one oxygen O atom.
It has the same molecular structure whether it is a gasliquidor solid. Although its physical state may change because of different amounts of energy, its atomic structure remains the same. So what is a chemical change in matter? Let's start with that glass of pure water. If the formula of water were to change, that would be a chemical change.
Physics for Kids: Heat Energy
If you could add a second oxygen atom to a water H2O molecule, you would have hydrogen peroxide H2O2. The molecules would not be "water" anymore. In reality, there are a variety of steps that go into creating hydrogen peroxide from water. Physical changes are related to changes in the immediate environment such as temperature, pressure, and other physical forces.