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How is the scientific method used to solve problems?

Scientific method used to solve problems by keen observations, rational analysis, and experimentation.


Closely observe the physical world around you.

How is the scientific method used to solve problems?

Scientific method used to solve problems by keen observations, rational analysis, and experimentation.


Closely observe the physical world around you.


Recognize a question or a problem.


An educated guess or a reasonable explanation. When the hypothesis can be tested by experiment, it qualifies as a scientific hypothesis


Consequences that can be observed if the hypothesis is correct. The consequences should be absent if the hypothesis is not correct.


Formulate the simplest general rule that organizes the hypothesis, predicted effects, and experimental findings.

What is the principle of falsifiability?

For a hypothesis to be considered scientific it must be testable?it must, in principle, be capable of being proven wrong.


A phenomenon about which competent observers can agree.


A synthesis of a large body of information that encompasses well-tested hypotheses about certain aspects of the natural world.


A general hypothesis or statement about the relationship of natural quantities that has been tested over and over again and has not been contradicted. Also known as a principle.


which serves to either support or counter a scientific theory or hypothesis.


is a test carried out in order to discover whether a theory is correct or what the results of a particular course of action would be .

What did Galileo do to challenge Aristotle?s belief that heavy objects fall faster than lighter objects?

Galileo very carefully examined Aristotle?s hypothesis. Then he did something that caught on and changed science forever. He experimented. Galileo showed the falseness of Aristotle?s claim with a single experiment?dropping heavy and light objects from the Leaning Tower of Pisa. Legend tells us that they fell at equal speeds. In the scientific spirit, one experiment that can be reproduced outweighs any authority, regardless of reputation or the number of advocates.

What is a system?

A system is a combination of related parts organized into a complex whole.

How are systems used to study science/biology?

As per the definition of systems that it is a combination of related parts organized into a complex whole. The Scientists studies the thousands of genes and their protein products. And research how the activities of these myriad molecules are coordinated in the development and maintenance of cells and whole organisms. And this research is now the approach called system biology.

What is the difference between inductive and deductive reasoning?

Deductive reasoning involves moving from generalities to specifics by working through a series of reasoned statements. Inductive reasoning, on the other hand, takes a series of specific observations and tries to expand them into a more general theory.

How is creativity used in science?

Creativity is used in Science by involving mental process through creative problem solving and the discovery of new ideas or concepts, or new associations of the existing ideas or concepts, fuelled by the process of either conscious or unconscious insight. From a scientific point of view, the products of creative thought (sometimes referred to as divergent thought) are usually considered to have both originality and appropriateness. Although intuitively a simple phenomenon, it is in fact quite complex. It has been studied from the perspectives of behavioural psychology, social psychology, psychometrics, cognitive science, artificial intelligence, philosophy, aesthetics, history, economics, design research, business, and management, among others. The studies have covered everyday creativity, exceptional creativity and even artificial creativity. Unlike many phenomena in science, there is no single, authoritative perspective or definition of creativity. And unlike many phenomena in psychology, there is no standardized measurement technique

How are hypotheses used in scientific inquiry?

For a hypothesis to be considered scientific it must be testable?it must, in principle, be capable of being proven wrong then a scientific inquiry will be started. Scientific inquiry have two functions: first, to provide a descriptive account of how scientific inquiry is carried out in practice, and second, to provide an explanatory account of why scientific inquiry succeeds as well as it appears to do in arriving at genuine knowledge of its objects basing on the formulation of the hypothesis. The classical model of scientific inquiry derives from Aristotle, who distinguished the forms of approximate and exact reasoning, set out the threefold scheme of abductive, deductive, and inductive inference, and also treated the compound forms such as reasoning by analogy.

What elements are important when designing a controlled experiment?

Elements of challenge, adventure, and surprise along with careful planning, reasoning, creativity, cooperation, competition, patience and the persistence ,to overcome setbacks.

What's the difference between a hypothesis and a theory?

When a scientific hypothesis has been tested over and over again and has not been contradicted, it may become known as a law or principle. While the scientific theory is a synthesis of facts and well tested hypotheses.

What is the relationship between science and technology?

Science is concerned with gathering knowledge and organizing it. Technology lets humans use that knowledge for practical purposes, and it provides the instruments scientists need to conduct their investigations.

Explain how field studies are used in science.

Field study is used in Science by naturalists for the scientific study of free-living wild animals in which the subjects are observed in their natural habitat, without changing, harming, or materially altering the setting or behaviour of the animals under study. Field study is an indispensable part of biological science. It helps to reveal the habits and habitats of various organisms present in their natural surroundings.


a natural science concerned with the study of life and living organisms


is the science of matter and the changes it undergoes


the scientific study of matter, energy, force, and motion, and the way they relate to each other. Physics traditionally incorporates mechanics, electromagnetism, optics, and thermodynamics and now includes modern disciplines such as quantum mechanics, relativity, and nuclear physics.


the study of the structure of the Earth or another planet, especially its rocks, soil, and minerals, and its history and origins

earth science:

a science that deals with the Earth's physical properties, structure, or development,


the scientific study of the universe, especially of the motions, positions, sizes, composition, and behaviour of astronomical objects. These objects are studied and interpreted from the radiation they emit and from data gathered by interplanetary probes

What is the goal of using an integrated approach to study science?

give you a background in the sciences-Physics, Chemistry, Earth Sciences and Biology-to make you scientifically literate for today's technical world

Explain the limitations of science.

There are three primary areas for which science can't help answer questions. All of these have the same problem: The questions they present don't have testable answers. Since testability is so vital to the scientific process, these questions simply fall outside the venue of science. Science can't answer questions about value; Science can't answer questions of morality, finally, science can't help us with questions about the supernatural.

Explain the limitations of a scientific investigation.

Science deals only with hypotheses that are testable. Its domain is therefore restricted to the observable natural world. While scientific methods can be used to debunk various paranormal claims, they have no way of accounting for testimonies involving the supernatural. The term supernatural literally means ?above nature.? Science works within nature, not above it. Likewise, science is unable to answer philosophical questions, such as ?What is the purpose of life?? or religious questions, such as ?What is the nature of the human spirit?? Though these questions are valid and may have great importance to us, they rely on subjective personal experience and do not lead to testable hypotheses.

How does biology integrate other disciplines? Give an example.

Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Integration of biology with other disciplines is recognized on the basis of the scale at which organisms are studied and the methods used to study them. Example is the Molecular biology. It is the study of biology at a molecular level. This field overlaps with other areas of biology, particularly with genetics and biochemistry. Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interrelationship of DNA, RNA, and protein synthesis and learning how these interactions are regulated.

Describe the themes that unify biology.

1. Cell- The cells are every organism's basic units of structure and function. 2. Heritable Information - The continuity of life depends on the inheritance of biological information in the form of DNA molecules. This genetic information is encoded in the nucleotide sequences of the DNA. 3. Emergent properties of Biological Systems - The living world hsa a hierarchical organization, extending from molecules to the biosphere. 4. Regulation - Feedback mechanisms regulate biological systems. 5. Interaction with the environment - Organisms are open systems that exchange material and energy with their surroundings. 6. Energy and life - All organisms must perform work, which requires energy. 7. Unity and Diversity - Three domains of life: Bacteria, Archaea and Eukarya 8. Evolution - Core theme, explains both the unity and the diversity of life. 9. Structure and function - Form and function are correlated at all levels of biological organization. 10. Scientific inquiry - the process of Science includes observation-based discovery and the testing of explanations through hypothesis-based inquiry. 11. Science, Technology and society - many technologies are goal-oriented applications of Science.


A unit of mass in the metric system, equal to 0.001 kilogram or 0.035 ounce.


The basic unit of liquid volume or capacity in the metric system, equal to 1.06 quart or 2.12 pints.


a unit of linear measurement equivalent to one-millionth of a meter.


Average speed. is a unit of speed or velocity, expressing the number of kilometers traveled in one hour


a unit of length equal to one thousandth of a meter.

meters/second/second (m/s2):

a unit of velocity and the time during which the velocity changes.


is the rate of flow of 1 coulomb of charge per second.

pH units:

a measure of acidity or alkalinity in which the pH of pure water is 7, with lower numbers indicating acidity and higher numbers indicating alkalinity.


unit of force equivalent to the force that produces an acceleration of one meter per second per second on a mass of one kilogram


the unit of electromotive force and electric potential difference equal to the difference between two points in a circuit carrying one ampere of current and dissipating one watt of power


unit of electrical resistance, equal to the resistance between two points on a conductor when a potential difference of 1 volt produces a current of 1 ampere.


unit of energy or work, equal to the work done when the application point of a one Newton force moves one meter in the direction of application


a unit of electrical voltage or potential difference equal to one thousandth of a volt


One billionth (10 -9 ) of a meter.


The unit of mass. One kilogram (symbol kg) is the mass of 1 liter (symbol L) of water at .4 degrees C.


unit of absolute temperature, equal to 1/273.16 of the absolute temperature of the triple point of water, equivalent to one degree Celsius

Grams per cubic centimeter (g/cm3):

unit of length, equivalent to approximately 1.094 yd or 39.37 in.


unit of power equal to the power produced by a current of one ampere acting across a potential difference of one volt.


unit of power equal to the power produced by a current of one ampere acting across a potential difference of one volt.

Why do we use machines?

We use machine to make work easier to perform.

What is the equation for work?

W = F x d

How does a simple machine affect work output?

A machine makes work easier to perform

How does a simple machine affect force output?

By accomplishing one or more of the following functions: 1. transferring a force from one place to another, 2. changing the direction of a force, 3. increasing the magnitude of a force, or 4. increasing the distance or speed of a force.

What is the difference between force output and work output?

A force output is the force that is exerted from the input force to create motion of the resisting object. The input force can be less or more then the output force while the work output is the energy output, which for simple machines is always less than the energy input, even though the forces might be drastically different.

List the types of simple machines.

Lever, Wheel and Axle, Pulley, Inclined Plane, Wedge and Screw

What is the mechanical advantage of using each type of simple machines?

1. Lever ? the mechanical advantage of a lever is the ratio of the length of the lever on the applied force side of the fulcrum to the length of the lever on the resistance force side of the fulcrum. 2. Wheel and Axle -The mechanical advantage of a wheel and axle is the ratio of the radius of the wheel to the radius of the axle 3. Pulley-The mechanical advantage of a moveable pulley is equal to the number of ropes that support the moveable pulley. 4. Inclined Plane -The mechanical advantage of an inclined plane is equal to the length of the slope divided by the height of the inclined plane. 5. Wedge -The mechanical advantage of a wedge can be found by dividing the length of either slope (S) by the thickness (T) of the big end. 6. Screw-the total mechanical advantage is equal to the circumference of the simple machine to which the effort force is applied divided by the pitch of the screw.

What is gravitational force?

The attractive force between objects due to mass.

Explain what happens to the gravitational force when there is a change in mass and/or distance.

The greater the distance from Earth?s centre, the less the gravitational force on an object. In Newton?s equation for gravity, the distance term d is the distance between the centers of the masses of objects attracted to each other. But no matter how great the distance, gravity approaches, but never quite reaches, zero. There is still a gravitational attraction between any two masses, no matter how far apart they are. Gravity gets weaker with distance the same way a light gets dimmer as you move farther from it.

Use an example to explain the inverse-square law.

Ex. In a typical classroom with a teachers voice signal of 65 decibels at a three-foot distance from the teacher; at 6 feet away the sound intensity will be 59 decibels and at twelve feet it will diminish down to 53 decibels.

What is projectile motion?

A projectile motion involves two components of motion ? vertical and horizontal. Characteristically, motion in one direction is independent of motion in another direction.

How does an object become a satellite?

If an apple or anything else moves fast enough so that it?s curved path matches the Earth?s curvature, it becomes a satellite.

What happens to a satellite when its speed exceeds 8 km/s?

For speeds higher than 8 km/s, the satellite's orbit is elliptical instead of circular. If speed exceeds 11.2 km/s then the satellite escapes Earth because gravity weakens (as object gets further away) and never slows the satellite enough to return it back towards Earth.

Explain the role of gravity in the formation of solar systems and galaxies.

Planets, stars, galaxies and solar systems are formed because of gravity. Planets are formed when pieces of debris are gravitationally attracted, so they compact together to make a bigger piece. More and more material is attracted until object is huge. Now that the planet is massive enough, its gravity is strong enough to pull everything down to a center point, making the planet spherical. Stars are formed when a nebulae gasses compact because of gravity. The temperature reaches a minimum of 18,000,000°F, nuclear fusion begins and a star is formed. Gravity turns the star spherical just like it does to planets. A solar system, is a group of planets and other object such as comets and meteors that orbit a central star, like our sun. A solar system is gravitationally bound together. All the planets and object are gravitationally bound. The central star keeps everything in orbit around it, because of gravity. So the universe is only possible because of gravity.

List the ways that gravity affects the objects in the solar system.

The solar system is made up of the sun, its planets, natural satellites, asteroids, meteoroids, and comets. Each of these bodies are held to each other by the force of gravity The planets move almost in circular elliptical orbits based on the force of gravity. The sun's gravitational pull is the most powerful gravitational force in the solar system. The other heavenly bodies have a much smaller gravitational force on one another called perturbations. The planets orbit the sun in the same counterclockwise direction

Why does the same side of the Moon always face the Earth?

The Moon in fact does spin, although quite slowly?about once every 27 days. This monthly rate of spin matches the rate at which the Moon revolves about Earth.

Explain the relationship between thermal energy and gravitational force in a star?s life cycle.

Gravitational force between the gaseous particles in a protostar results in an overall contraction of this huge ball of gas, and its density increases still further as matter is crunched together, with an accompanying rise in pressure and temperature. When the central temperature reaches about 10 million K, hydrogen nuclei begin fusing to form helium nuclei. This thermonuclear reaction, converting hydrogen to helium, releases an enormous amount of radiant and thermal energy. The ignition of nuclear fuel marks the change from protostar to star.

How does gravity affect light in a black hole?

A black hole is the remains of a supergiant star that has collapsed into itself. It is so dense and has such an intense gravitational field that light cannot escape from it. We can see why gravity is so great in the vicinity of a black hole by considering the change in the gravitational field at the surface of any star that collapses.

How does gravitational field affect light (refer to the footnote on p. 658)?

Light, just like massive things, is affected by gravity. Just as we fail to see the curvature of a high-speed bullet when viewed along short segments, we most often fail to see the curvature by gravity of even higher speed light. Light does curve in a gravitational field.

What is the electrical force?

The electrical force, like gravitational force, decreases inversely as the square of the distance between the charges. This relationship, which was discovered by Charles Coulomb in the eighteenth century, is called Coulomb?s Law. It states that, for two charged objects that are much smaller than the distance between them, the force between them varies directly as the product of their charges and inversely as the square of the separation distance. The force acts along a straight line from one charge to the other.

Explain the conservation of charge.

The principle that the total electric charge of an isolated system remains constant, no matter what internal changes take place.

How is Coulomb?s law regarding electrical force similar to Newton?s law of universal gravitation?

Coulomb?s Law of electrical force, like gravitational force of Newton?s law, decreases inversely as the square of the distance between the charges.

How does Coulomb?s law differ from Newton?s law of universal gravitation?

The most important difference between gravitational force of Newton?s law and electrical forces of Coulomb?s law is that electrical forces may be either attractive or repulsive, whereas gravitational forces are only attractive

Describe the inverse-square law.

is any physical law stating that some physical quantity or strength is inversely proportional to the square of the distance from the source of that physical quantity.

What happens when a charged particle enters an electric field?

If you place a charged particle in an electric field, it will experience a force. The direction of the force on a positive charge is the same direction as the field.

How can electric potential energy increase?

If the particle is released, it accelerates in a direction away from the sphere, and its electric potential energy changes to kinetic energy, thus increases the electric potential energy

Explain what volt means when referring to a nine-volt battery.

It means that one of the battery terminals is 9V higher in potential than the other one. It also means that, when a circuit is connected between these terminals, each coulomb of charge in the resulting current will be given 9 J of energy as it passes through the battery (and 9 J of energy is ?spent? in the circuit).

Explain why glass is an insulator whereas silver is a conductor.

Silver is a good electrical conductor for the same reason they are good heat conductors: atoms of metals have one or more outer electrons that are loosely bound to their nuclei. These are called free electrons. It is these free electrons that conduct through a metallic conductor when an electric force is applied to it, making up a current. The electrons in a glass are tightly bound and belong to particular atoms. Consequently, it isn?t easy to make them flow. These materials are poor electrical conductors for the same reason they are generally poor heat conductors. Such a material is called a good insulator

Why is a potential difference needed for an electric current?

When the ends of an electrical conductor are at different electric potentials? when there is a potential difference?charges in the conductor flow from the higher potential to the lower potential. The flow of charges persists until both ends reach the same potential. Without a potential difference, no flow of charge will occur.

What is an ampere?

An ampere is the rate of flow of 1 coulomb of charge per second. (That?s a flow of 6.25 billion billion electrons per second.)

What is direct current (DC)

an electric current flowing in one direction only.

Alternating current (AC).

is electric current that repeatedly reverses its direction; the electric charges vibrate about relatively fixed positions. In the United States, the vibrational rate is 60 Hz

Explain the relationship between current, resistance, and voltage in Ohm?s law.

the amount of current in a circuit is directly proportional to the voltage established across the circuit and is inversely proportional to the resistance of the circuit

What is a resistor?

a component of an electrical circuit that has resistance and is used to control the flow of electric current

How does a parallel circuit differ from a series circuit?

Components connected in series are connected along a single path, so the same current flows through all of the components. Components connected in parallel are connected so the same voltage is applied to each component. In a series circuit, the current through each of the components is the same, and the voltage across the components is the sum of the voltages across each component while in a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component.

How does magnetic force differ from electric force?

Whereas electric charges produce electrical forces, regions called magnetic poles give rise to magnetic forces. The difference is that electric charges can be isolated, magnetic poles cannot. Electrons and protons are entities by themselves. But the north and south poles of a magnet are like the head and tail of the same coin. If you break a bar magnet in half, each half still behaves as a complete magnet. Break the pieces in half again, and you have four complete magnets. You can continue breaking the pieces in half and never isolate a single pole. Even if your pieces were one atom thick, there would still be two poles on each piece, which suggests that the atoms themselves are magnets

Explain what makes an object magnetic.

in the electrons of the atoms that make up the object magnetic. These electrons are in constant motion. Two kinds of electron motion produce magnetism: electron spin and electron revolution. In most common magnets, electron spin is the main contributor to magnetism. Every spinning electron is a tiny magnet. A pair of electrons spinning in the same direction creates a stronger magnet.

How does a compass work?

The compass functions as an indicator to "Magnetic North" because the magnetic bar at the heart of the compass aligns itself to one of the lines of the Earth's magnetic field.

What is an electromagnet?

A magnet consisting of a core, often made of soft iron that is temporarily magnetized by an electric current flowing through a coil that surrounds it

Describe how moving charges interact with a magnetic field.

A magnetic field is produced by moving electric charges.

Why does a magnet deflect a current-carrying wire?

A charged particle has to be moving to interact with a magnetic field. Charges at rest don?t respond to magnets. But, when they are moving, charged particles experience a deflecting force. The force is greatest when the particles move at right angles to the magnetic field lines. At other angles, the force is less, and it becomes zero when the particles move parallel to the field lines. The force is always perpendicular to the magnetic field lines and perpendicular to the velocity of the charged particle. So a moving charge is deflected when it crosses through a magnetic field, but, when it travels parallel to the field, no deflection occurs.

Explain electromagnetic induction.

the induction of voltage when a magnetic field changes with time.

How do electric motors work?

An electric motor uses electrical energy to produce mechanical energy, very typically through the interaction of magnetic fields and current-carrying conductors. An electric motor is all about magnets and magnetism: A motor uses magnets to create motion. The fundamental law of all magnets: Opposites attract and likes repel. So if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of the other. On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel south). Inside an electric motor, these attracting and repelling forces create rotational motion.

What is potential energy?

The energy that a body or system has stored because of its position in an electric, magnetic, or gravitational field, or because of its configuration. Symbol VEp

Potential energy

Example: Lifting a weight and holding it there.

Electrical potential energy

Example: Ionization energy of the electron in a hydrogen atom.

Chemical potential energy

Example: fossil fuel like coal. The energy is only released when a chemical reaction takes place, ie burning it with oxygen.

Gravitational potential energy

Example: The water behind a dam.

What factors affect the amount of gravitational potential energy?

Weight and height of an object

Explain what happens to kinetic energy when the mass and speed of an object changes.

Kinetic energy also changes because the kinetic energy of an object depends on its mass and its speed. It is equal to half the mass multiplied by the square of the speed, multiplied by the constant ½.

List examples of different types of kinetic energy.

A car moving along a road has kinetic energy, Energy can be transferred from one object to another, such as when a rolling bowling ball transfers some of its kinetic energy to the pins and sets them in motion. Energy also transforms, or changes form. For example, the gravitational potential energy of a raised ram transforms to kinetic energy when the ram is released from its elevated position. And, when you raise a pendulum bob against the force of gravity, you do work on it. That work is stored as potential energy until you let the pendulum bob go. Its potential energy transforms to kinetic energy as it picks up speed and loses elevation.

Explain the law of conservation of energy.

Whenever energy is transformed or transferred, none is lost and none is gained. In the absence of work input or output, the total energy of a system before some process or event is equal to the total energy after.

Define thermal energy.

Energy resulting from the motion of particles. Thermal energy is a form of kinetic energy and is transferred as heat.

Newton?s first law of motion

Every object continues in a state of rest, or in a state of motion in a straight line at a constant speed, unless it is compelled to change that state by forces exerted on it.

Newton?s second law of motion

The acceleration produced by a net force on an object is directly proportional to the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object.

Newton?s third law of motion

whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.

Newton?s First Law of Motion-

Examples: 1. when you play tug of war. As one side pulls on the other, there is sometimes no motion at all. But there are forces are work. Those forces are balanced a and so though there is force, there is no motion. 2. a moving car will stop if it hits another moving car, but not if you step on the floorboard because stepping on the floorboard is an internal force. 15 3. You may push a piano and it may not move. That is because the force of gravity uses the weight of the piano as a type of force that keeps balance unless an outside force or external force creates an imbalance. The harder you push, the more of a chance you have of creating an unbalanced force. If you push hard enough you will create an unbalanced force and the piano

Newton?s Second Law of Motion-

Examples: 1. if you are pushing on an object, causing it to accelerate, andthen you push, say, three times harder, the acceleration will be three times greater. 2. if you are pushing equally on two objects, and one of the objects has five times more mass than the other, it will accelerate at one fifth the acceleration of the other. 3. if a train hits another train of equal force and speed, they will both go the same distance and feel the same force. But if the first train is hooked to a second, the single train will go twice the distance of the double train and will feel twice the force.

Newton?s Third Law of Motion-

Examples: 1. A classic example is any rocket launch. A chemical reaction occurs in the rocket engine. The engine pushes out gases at a very high pressure from the bottom of the engine. This is the action. The gases in turn, exert an upward force on the rocket propelling it in the opposite (upward) direction - into space. This is the reaction. 2. While swimming or rowing, your hands / oars push the water behind - Action. The water pushes you in the opposite (forward) direction - Reaction. 3. A bird pushes air down while flying (action), Since forces result from mutual the air must also be pushing the bird upwards (equal and opposite reaction). This allows the bird to fly

What is a wave?

A disturbance that travels from one place to another transporting energy, but not necessarily matter, along with it.


the modulation of the amplitude of a radio wave in such a way as to encode the wave with audio or visual information.


The distance from the top of one crest to the top of the next one or, equivalently, the distance between successive identical parts of the wave.


The number of to-and-fro vibrations an oscillator makes in a given time, or the number of times a particular point on a wave (for example the crest) passes a given point in a given time.


The time required for a vibration or a wave to make a complete cycle; a horizontal row in the periodic table.

Summarize radio waves.

AM radio waves are usually measured in kilohertz, while FM radio waves are measured in megahertz. These radio-wave frequencies are the frequencies at which electrons are forced to vibrate in the antenna of a radio station?s transmitting tower. The frequency of the vibrating electrons and the frequency of the wave produced are the same.

transverse wave

A wave in which the medium vibrates in a direction perpendicular (transverse) to the direction in which the wave travels

longitudinal wave.

A wave in which the medium vibrates in a direction parallel (longitudinal) with the direction in which the wave travels. Compressions and rarefactions are characteristics of longitudinal waves.

transverse (an example)

Water waves. The water moves up and down while the wave travels over the surface of the water.

longitudinal waves (an example)

Sound waves. The air vibrates back and forth along the same direction as the wave is traveling.

What changes the pitch of sound?

The rate of vibration of air molecules next to a vibrating object changes the pitch of sound.

Explain how different factors affect the speed of sound?

The speed of sound depends on wind conditions, temperature, and humidity. It does not depend on the loudness or the frequency of the sound; all sounds travel at the same speed in a given medium. The speed of sound in dry air at 0°C is about 330 meters per second, which is nearly 1200 kilometers per hour. Water vapor in the air increases this speed slightly. Sound travels faster through warm air than cold air. because the faster-moving molecules in warm air bump into each other more frequently and, therefore, can transmit a pulse in less time.* For each degree rise in temperature above 0°C, the speed of sound in air increases by 0.6 meter per second. Thus, in air at a normal room temperature of about 20°C, sound travels at about 340 meters per second. In water, sound speed is about four times its speed in air; in steel, it?s about fifteen times its speed in air.

Why do submerged objects appear to be nearer the surface than they actual are?

Refraction causes many illusions. One of them is the apparent bending of a stick that is partially submerged in water. The submerged part appears closer to the surface than it actually is.

Explain reflection, refraction, and diffraction of sound and light.

Reflection - The returning of a wave to the medium from which it came when it hits a barrier. Refraction - The bending of waves due to a change in the medium. Diffraction - Any bending of light by means other than reflection and refraction.

Give examples of constructive and destructive interference.

An intriguing property of all waves is interference?the combined effect of two or more waves overlapping. Consider transverse waves: When the crest of one wave overlaps the crest of another, their individual effects add together. The result is a wave of increased amplitude. This is constructive interference. When the crest of one wave overlaps the trough of another, their individual effects are reduced. The high part of one wave simply fills in the low part of another. This is destructive interference.

Describe how the Doppler Effect explains the change in pitch of a fire-engine siren and the movement of a galaxy.

The Doppler Effect is evident when you hear the changing pitch of an ambulance or fire-engine siren. When the siren is approaching you, the crests of the sound waves encounter your ear more frequently, and the pitch is higher than normal. And when the siren passes you and moves away, the crests of the waves encounter your ear less frequently, and you hear a drop in pitch. The Doppler Effect also occurs for light waves. When a light source approaches, there is an increase in its measured frequency; when it recedes, there is a decrease in its frequency. Galaxies, too, show a red shift in the light they emit. This observation was first made by American astronomer Edwin Hubble. When Hubble observed galaxies through his telescope, he noticed that the colours of the light emitted by their elements seemed to be red-shifted. This implied that the galaxies must be moving away from Earth. Further, Hubble?s observations established that the farther a galaxy is from Earth, the faster it is moving away. This is the basis of our current belief that the universe is ever-expanding.


transfers energy through vibrations. The wave in which the medium vibrates in a direction perpendicular (transverse) to the direction in which the wave travels.


transfers energy through vibrations. The wave in which the medium vibrates in a direction parallel (longitudinal) with the direction in which the wave travels.

Sound, infrasonic, ultrasonic, radio

Hearing any sound occurs because air molecules next to a vibrating object are themselves set into vibration and energy is transferred. These, in turn, vibrate against neighbouring molecules, which, in turn, do the same, and so on. As a result, rhythmic patterns of compressed and rarefied air emanate from the sound source. The resulting vibrating air sets your eardrum into vibration, which, in turn, sends cascades of rhythmic electrical impulses along nerves in the cochlea of your inner ear and into the brain. Thus, when you hear a high-pitched sound, a high-frequency wave from a quickly vibrating source sets your eardrum into fast vibration. Bass guitars, foghorns, and deep-throated bullfrogs vibrate slowly, making low-pitched waves that set your eardrums into slow vibration. Hearing any sound occurs because air molecules next to a vibrating object are themselves set into vibration. These, in turn, vibrate against neighbouring molecules, which, in turn, do the same, and so on. As a result, rhythmic patterns of compressed and rarefied air emanate from the sound source. The resulting vibrating air sets your eardrum into vibration, which, in turn, sends cascades of rhythmic electrical impulses along nerves in the cochlea of your inner ear and into the brain. Thus, when you hear a high-pitched sound, a high-frequency wave from a quickly vibrating source sets your eardrum into fast vibration. Bass guitars, foghorns, and deep-throated bullfrogs vibrate slowly, making low-pitched waves that set your eardrums into slow vibration.


As the ocean waves propagate, their energy is transported. a disturbance that travels from one place to another transporting energy, but not necessarily matter, along with it


Tsunami waves are mechanical waves and thus energy transfer is through the phenomenon of compression and rarefaction. These waves move through their source towards the onshore areas due to the additional impact of wind on the surface of water. This phenomenon of water wave movement can be understood as the generation of ripples on water surface when disturbed by any external impact.


S-waves are transverse?they vibrate the particles of their medium up and down and side-to side, and they travel more slowly than P-waves. S-waves can only travel through solid materials in which where the energy is transferred

Describe how a tsunami transfers energy.

Tsunami transfers energy through the phenomenon of compression and refraction. It is a catastrophic ocean wave, usually caused by a submarine earthquake occurring less than 50 km (30 miles) beneath the seafloor, with a magnitude greater than 6.5 on the Richter scale. Underwater or coastal landslides or volcanic eruptions also may cause a tsunami. A tsunami can have a wavelength in excess of 100 km and period on the order of one hour. Because it has such a long wavelength, a tsunami is a shallow-water wave. Shallow-water waves move with a speed equal to the square root of the product of the acceleration of gravity and the water depth. The rate at which a wave loses its energy is inversely related to its wavelength. A tsunami not only propagates with a high speed, it also can travel a great, transoceanic distance with only limited energy loss. Earthquakes generate tsunamis when the sea floor abruptly deforms and displaces the water above from its equilibrium position. Waves are formed as the displaced water under the influence of gravity attempts to regain its equilibrium. The initial size of a tsunami is determined by the amount of vertical sea floor deformation.

Gamma Rays

The range of electromagnetic waves that extends infrequency from radio waves to gamma rays. Gamma Rays have frequencies above 1019 Hz, and therefore have energies above 100 keV and wavelength less than 10 picometers


a high-energy electromagnetic radiation that can penetrate solids and ionize gas. It has a wavelength between 0.01 and 10 nanometres, which is between gamma rays and ultraviolet light with a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3 × 1016 Hz to 3 × 1019 Hz) and energies in the range 120 eV to 120 keV.

Ultraviolet Radiation

Ultraviolet (UV) radiation is defined as that portion of the electromagnetic spectrum between x rays and visible light with a wavelength shorter than that of visible light, but longer than xrays, in the range 10 nm to 400 nm, and energies from 3eV to 124 eV


the portion of the invisible electromagnetic spectrum consisting of radiation with wavelengths in the range 750 nm to 1 mm, between light and radio waves and covers the range from roughly 300 GHz (1 mm) to 400 THz (750 nm) with energy range from 1.24meV ? 1.24eV


an electromagnetic wave whose wavelength ranges from 1 mm to 30 cm. Use: radar, radio transmissions, cooking or heating devices with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and 300 GHz.

Radio Waves (AM and FM)

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Like all other electromagnetic waves, they travel at the speed of light with frequencies lower than around 300 GHz (or, equivalently, wavelengths longer than about 1 mm) with energy from 12.4feV ? 1.24meV.

Visible Light

This makes up less than a millionth of 1% of the electromagnetic spectrum. The lowest frequency of light we can see with our eyes appears red. The highest visible frequencies, which are nearly twice the frequency of red light, appear violet. Wavelengths are between 380 nm and 760 nm (790?400 terahertz).

How does light act as both a wave and a particle?

We have described light as a wave. The earliest ideas about the nature of light, however, were that light was composed of tiny particles. Evidently, light has both a wave nature and a particle nature?a wave?particle duality. It reveals itself as a wave or particle depending on how it is being observed. Simply stated, light behaves as a stream of photons when it interacts with a sheet of metal or other detector and it behaves as a wave in travelling from a source to the place where it is detected. Light travels as a wave and hits as a stream of photons. The fact that light exhibits both wave and particle behaviour is one of the most interesting surprises that physicists discovered in the twentieth century.

What is an electromagnetic wave?

Are the mechanism by which electromagnetic energy (electromagnetic radiation) moves. They are composed of two components: an electric wave, or an electric field, and a magnetic wave or magnetic field.

How are all electromagnetic waves the same? How do they differ?

The electromagnetic spectrum is a continuous range of electromagnetic waves extending from radio waves to gamma rays. The descriptive names of the sections are merely a historical classification, for all the waves are the same in nature, differing principally in frequency and wavelength; all travel at the same speed.

Describe the general structure of an atom.

The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons). The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral; otherwise it has a positive or negative charge and is an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element.

What makes an atom radioactive?

Atoms with unstable nuclei are said to be radioactive. Sooner or later, they break down and eject energetic particles and emit electromagnetic radiation.

Explain the difference between an alpha particle, a beta particle, and a gamma ray.

An alpha particle is the combination of two protons and two neutrons (in other words, it is the nucleus of the helium atom, atomic number 2). Alpha particles are relatively easy to shield against because of their relatively large size and their double positive charge (+2) whileW A beta particle is an electron ejected from a nucleus. Once ejected, it is indistinguishable from an electron in a cathode ray or in an electrical circuit, or from an electron orbiting the atomic nucleus. The difference is that a beta particle originates inside the nucleus?from a neutron. As we shall soon see, the neutron becomes a proton once it loses the electron that has become a beta particle. A beta particle is normally faster than an alpha particle, and it carries only a single negative charge (-1 ) and Gamma rays are the high-frequency electromagnetic radiation emitted by radioactive elements. Like photons of visible light, a gamma ray is pure energy. The amount of energy in a gamma ray, however, is much greater per photon than in visible light, ultraviolet light, or even X-rays. Because they have no mass or electric charge, and because of their high energies, gamma rays are able to penetrate through most materials.

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