In terms of the motion of the particles of the medium, a sound wave can be best described as a ____ wave.

Definition of Longitudinal Waves and Transverse Waves:

There are a variety of wave types that can exist in a medium. The two most common types are longitudinal and transverse.

A transverse wave is a type of wave in which particles of the medium vibrate in a direction which is perpendicular to the direction which the wave moves.

A longitudinal wave is a type of wave in which particles of the medium vibrate in a direction which is parallel to the direction which the wave moves.

As a sound wave moves from a source (say a tuning fork ) to an observer, particles of the medium vibrate about a fixed position. The vibrations are in a back-and-forth direction aligned parallel to the line connecting the source and the observer.

One way of representing a sound wave is by means of a pressure plot. The vibration of particles of the medium about a fixed position results in regions of high pressure (compressions) and low pressure(rarefactions) in the space surrounding the source. These compressions and rarefactions are regularly spaced and travel from the source to the observer. The arrival of these regions at the observer's location (or any location) results in fluctuations of pressure with respect to time at that location. If a plot of pressure versus time at any location were constructed for a traveling sound wave, then the plot would show a sinusoidal variation in pressure with respect to time. The sinusoidal nature of the the graph might lead a student to believe that sound is a transverse wave. But don't be fooled! Sound is not a transverse wave since particles of the medium do not vibrate back and forth in a direction perpendicular to the direction that the sound wave moves.

In what way can a sound wave be categorized?

Waves are often categorized as being electromagnetic waves or mechanical waves. A sound wave is best categorized as a _____ wave.

Definition of Mechanical Waves and Electromagnetic Waves:

There are a variety of ways to categorize waves. One way to categorize waves is to say that they are either mechanical waves or electromagnetic waves.

A mechanical wave is a type of wave which requires a medium in order to transport its energy from one location to another.

An electromagnetic wave is a type of wave which can transport its energy through a region of space void of matter. Electromagnetic waves can travel through a vacuum.

Sound waves travel from the source to the observer by means of particle-to-particle interaction. The source disturbs the first particle of the medium - perhaps by pushing it forward. This particle in turn pushes on the second particle of the medium, pushing it forward as well. The second particle pushes the third particle forward which in turn pushes the ... . As a result of this particle-to-particle interaction, a sound wave travels through the medium from one location to another. However, if there were no particles in the region of space surrounding the source, then there would be no sound wave traveling through that region of space. The source could vibrate, but there would be no particles surrounding it that could be forced to vibrate about a fixed position. Sound waves require a medium - solid, liquid or gas - in order to transport its energy from the source to the observer.

What is the difference between an electromagnetic and a mechanical wave? In which category does a sound wave fall?

Can sound travel through a vacuum?

Sound cannot travel through ____. List all that apply ... .

Definition of Mechanical Waves and Electromagnetic Waves:

There are a variety of ways to categorize waves. One way to categorize waves is to say that they are either mechanical waves or electromagnetic waves.

A mechanical wave is a type of wave which requires a medium in order to transport its energy from one location to another.

An electromagnetic wave is a type of wave which can transport its energy through a region of space void of matter. Electromagnetic waves can travel through a vacuum.

Sound waves travel from the source to the observer by means of particle-to-particle interaction. The source disturbs the first particle of the medium - perhaps by pushing it forward. This particle in turn pushes on the second particle of the medium, pushing it forward as well. The second particle pushes the third particle forward which in turn pushes the ... . As a result of this particle-to-particle interaction, a sound wave travels through the medium from one location to another. However, if there were no particles in the region of space surrounding the source, then there would be no sound wave traveling through that region of space. The source could vibrate, but there would be no particles surrounding it that could be forced to vibrate about a fixed position. Sound waves require a medium - solid, liquid or gas - in order to transport its energy from the source to the observer. Sound waves cannot travel through a vacuum.

What is the difference between an electromagnetic and a mechanical wave? In which category does a sound wave fall?

Can sound travel through a vacuum?

Sammy is talking to Sally. Position A is a position in front of Sammy's mouth. Position B is a position in front of Sally's ear. In order for Sally to hear Sammy's voice, air particles must ____.

Propagation of Sound Waves:

Sound waves move (propagate) through a medium by means of particle-to-particle interaction. The source disturbs the immediately surrounding particles, causing them to vibrate about their fixed position at the same frequency as the source. These particles in turn force their nearest neighbors to vibrate about their fixed position which in turn forces their nearest neighbors to vibrate about their fixed position which in turn ... . As a result of this particle-to-particle interaction, a sound wave travels through the medium from one location to another.

A common misconception (wrong idea) regarding waves is that a wave involves the movement of matter from the source to other parts of a medium. In the case of a sound wave traveling through air, a student might believe that particles of air move at high speeds from the speaker to the hearer. But don't be fooled! Waves involve the transport of energy, not the transport of matter. When a sound wave travels through air, particles of air simply undergo a back-and-forth vibratory cycle about a fixed position. The air particles do not actually move from the speaker to the observer; they simply vibrate. Their vibrations force their nearest neighbors to vibrate which forces their nearest neighbors to vibrate which forces their nearest neighbors to vibrate.

How does a sound wave make its way from one location to another location?

TRUE or FALSE: In order to hear a person talking, air particles (or some kind of particle) must move from the mouth of the talking person to the ear of the listening person.

(Note: The actual true-false statement is randomly selected from a collection of statements and may differ from the one shown above.)

Propagation of Sound Waves:

Sound waves move (propagate) through a medium by means of particle-to-particle interaction. The source disturbs the immediately surrounding particles, causing them to vibrate about their fixed position at the same frequency as the source. These particles in turn force their nearest neighbors to vibrate about their fixed position which in turn forces their nearest neighbors to vibrate about their fixed position which in turn ... . As a result of this particle-to-particle interaction, a sound wave travels through the medium from one location to another.

A common misconception (wrong idea) regarding waves is that a wave involves the movement of matter from the source to other parts of a medium. In the case of a sound wave traveling through air, a student might believe that particles of air move at high speeds from the speaker to the hearer. But don't be fooled! Waves involve the transport of energy, not the transport of matter. When a sound wave travels through air, particles of air simply undergo a back-and-forth vibratory cycle about a fixed position. The air particles do not actually move from the speaker to the observer; they simply vibrate. Their vibrations force their nearest neighbors to vibrate which forces their nearest neighbors to vibrate which forces their nearest neighbors to vibrate.

How does a sound wave make its way from one location to another location?

A sound wave is often called a pressure wave because there are regions of high and low pressure established in the medium through which the sound wave travels. The regions of high pressure are known as ____ and the regions of low pressure are known as ____.

Definition of Compression and Rarefactions:

A compression is a region within a medium in which particles of that medium are smooshed together or compressed. A rarefaction is a region within a medium in which particles of that medium are pulled apart or spread out.

The vibration of particles of the medium about a fixed position results in compressions and rarefactions in the space surrounding the source. The compressions are high density regions and the rarefactions are low density regions. When the density of particles within any given region is high, the pressure associated with that region of space is high as well. Conversely, when the density of particles is relatively low, the pressure is relatively low as well. Thus, compressions are regarded as high pressure regions of space and rarefactions are considered low pressure regions of space.

Most students readily think of crests and troughs at the mention of the idea of waves. The picture of a water wave or a slinky wave with its high points (crests) and low points (troughs) is ingrained in our mind. These crest and trough positions are common for transverse waves in which particles of the medium vibrate in a direction perpendicular to the wave motion. But don't be fooled! Sound waves are not transverse waves and do not result in the formation of crests and troughs. Sound waves are longitudinal waves. In a longitudinal wave, particles of the medium do not vibrate perpendicular to the direction which the medium vibrate. As such, crests (large displacements above the resting position) and troughs (large displacements in the opposite direction). Sound waves produce compressions and rarefactions as a result of the longitudinal motion of the particles of the medium.

What are the high pressure and low pressure regions of a sound wave called?

The tines of a vibrating tuning fork create a sound which travels through a long tube. The diagram below portrays the presence of position of air molecules within the tube at an instant in time. Which of the labeled regions are compressions? List all that apply ... .

Definition of Compression and Rarefactions:

A compression is a region within a medium in which particles of that medium are smooshed together or pressed together. A rarefaction is a region within a medium in which particles of that medium are pulled apart or spread out.

The diagram shows a snapshot at one instant in time of the particles of air within the tube. The expected pattern of alternating compressions and rarefactions is observed within the tube. There are locations in which particles are smooshed or pressed together and locations in which particles are pulled apart or spread out.

What are compressions and rarefactions?

Suppose that you are watching a science fiction film involving two space ships in the deep void of outer space. In the film, an explosion occurs on space ship A. After seeing the fiery blast from a long distance away, the occupants of space ship B hear the loud boom of the blast. This is an example of _____.

Propagation of Sound Waves:

Sound waves move (propagate) through a medium by means of particle-to-particle interaction. The source disturbs the immediately surrounding particles, causing them to vibrate about their fixed position at the same frequency as the source. These particles in turn force their nearest neighbors to vibrate about their fixed position which in turn forces their nearest neighbors to vibrate about their fixed position which in turn ... . As a result of this particle-to-particle interaction, a sound wave travels through the medium from one location to another.

As discussed in the Physics Rules section above, sound waves travel through a medium by means of particle-to-particle interaction. The source sets surrounding particles vibrating about their fixed position. By means of particle-to-particle interaction, all particles within the medium are soon vibrating about their fixed position. Sound waves can travel through any medium in this fashion by means of particle-to-particle interaction. But don't be fooled! Sound waves cannot travel through no medium. That is, sound waves cannot travel through a region of space void of matter - a vacuum. In the absence of particles, sound waves no longer exist.

Definition of Mechanical Waves and Electromagnetic Waves:

There are a variety of ways to categorize waves. One way to categorize waves is to say that they are either mechanical waves or electromagnetic waves.

A mechanical wave is a type of wave which requires a medium in order to transport its energy from one location to another.

An electromagnetic wave is a type of wave which can transport its energy through a region of space void of matter. Electromagnetic waves can travel through a vacuum.

Can sound travel through a vacuum?

What is the difference between an electromagnetic and a mechanical wave? In which category does a sound wave fall?