The difference between Sound waves and Light Waves are: Sound Waves require a medium where Light Waves do not require a medium
Sound Waves
1. Require a medium.
2. Travel with a speed of 332 m/s at 0 C.
3. Are longitudinal waves consisting of compressions and rarefactions.
4. Are of different frequencies, giving notes of different pitches.
5. Do not travel far as their energy is dissipated easily.
Light Waves
1. Do not require a medium
2. Travel with a speed of 3 *108m/s.
3. Are electromagnetic waves consisting of varying electric and magnetic fields.
4. Are of different frequencies, resulting in different colors.
5. Can travel through a much greater distance.
The differences between light and sound are as follows:
· Light can be considered to be made of waves as well as particles. Sound is only a wave. It does not show particle nature.
· Light waves are electromagnetic waves while sound waves are mechanical waves.
· Light waves are transverse while sound waves are longitudinal.
· Light waves can travel in vacuum. Sound waves require a material medium to travel, and hence, cannot travel in vacuum.
· The speed of light in a medium is constant. The velocity of sound waves can change.
· In sound waves, the particles of the medium actually oscillate. In a light wave, the electric and magnetic vectors oscillate.
· Light waves can be polarized, but sound waves cannot.
· Light waves travel much faster than sound waves. The speed of light is a physical constant. Its value is exactly 299,792,458 meters per second in vacuum. The speed of sound is 343 meters per second in dry air at 20°C.
· And finally, a simple one - you canseelight while you can hearsound.
The key background to this question is the nature of sound waves and light waves. You’re right in that sound waves are a vibration traveling through an object, including "condensed" things like solids and liquids. In solids, those waves can consist of either alternating compressed and stretched regions, or regions wiggling sideways, compared to the direction the wave is traveling. Light is a wave of oscillating electric and magnetic fields perpendicular to the direction it’s going. Light can travel fine through a vacuum, which can have fields in it, but there can’t be sound in a vacuum
because there’s no stuff there to oscillate.
Audible sound has frequencies that cover a very big range, from about 20 Hz to 20,000 Hz, meaning that the pressure at your ear oscillates back and forth 20 to 20,000 times per second. Each frequency gives a different audible pitch. Visible light has frequencies from around 4*10^14 Hz to around 8*10^14 Hz. Each frequency gives a slightly different visible color. Not only are the light frequencies much higher, but the highest one is only about twice the lowest one. The sound frequencies are much lower, and the highest one is a thousand times higher than the lowest one. So you can see that there’s no direct match between the sound and light oscillations.
The Characteristics of Sound and Light Waves
There are many different kinds of waves. Waves can carry a little energy or a lot. They can be short or long. They can be rare or frequent. They can travel fast or slow. Sound waves, light waves, X-rays, microwaves, and ocean waves are but a few examples. All waves, however, share certain basic characteristics.
All waves have amplitude, wavelength, and frequency.
§ In order to understand these characteristics of waves, it may help you to represent a wave as a drawing on a graph. The X-axis (the horizontal line) represents the normal, or resting position.For example, the X-axis might represent a calm sea or a tight rope. The vibrational movements of the wave are shown on the Y-axis. The highest points on the graph are called peaks or crests. The lowest points are called troughs.
o Amplitude
Some waves are very high, while others are barely noticeable. The distance the wave rises depends on the amplitude of the wave.Amplitudeis the maximum distance the medium (the material through which a wave travels) moves away from its rest position. The higher the wave moves up-and-down as it vibrates, the larger the amplitude of the resulting waves.
· Wavelength
The distance between two consecutive (one after another) crests or troughs of a wave is called thewavelength. The wavelength can be measured from any point on a wave as long as it is measured to the same point on the next wave.
o Frequency
The number of complete waves, or complete cycles, per unit of time is called thefrequency. Because every complete wave has one crest and one trough, you can think of the frequency as the number of crests or troughs produced per unit time. The unit used to measure wave frequency is called the hertz (Hz). The frequency of a wave depends on the frequency at which its source is vibrating. Frequency, which is often used to describe waves, is an important characteristic. Frequency is used to distinguish one color of light from another, as well as one sound from another. For example, red light is different from blue light because red light has a lower frequency. A dog can hear a whistle that you cannot hear because dogs can hear sounds at higher frequencies than humans can.
Properties of Sound
There are millions of different sounds in everyday life. Each sound having certain characteristics that make it unique. Think about the many sounds you hear everyday. How you hear and describe a sound depends on the physical characteristics of the sound wave.
o Frequency and Pitch
Certain sounds are described as high, such as those produced by a piccolo, or low, such as those produced by a bass drum. A description of a sound as high or low is known as thepitchof the sound. The pitch of a sound depends on how fast the particles of a medium (the material through which a wave travels) vibrate. So the pitch of a sound depends on the number of waves produced in a given time.
Key point here: Sound waves that have a high frequency are heard as sounds of high pitch. A violin produces high-pitched sounds. Sound waves that have a low frequency are heard as sounds of low pitch. A tuba produces low-pitched sounds.
Frequency is an especially important characteristic of sound because the ear can respond to only certain frequencies. The normal human ear is capable of detecting from about 20 to 20,000 vibrations per second, or hertz.
Here is a helpful link for more information on sound waves:http://www.ronkurtus.com/physcien/sound.htm
Properties of Light
What does sunlight have in common with the X-rays used in a doctor's office? Are you surprised to learn that they are both waves? They're not matter waves that you can hear or feel. They are electromagnetic waves. Electromagnetic waves disturb electric and magnetic fields. These waves can be transmitted through a vacuum (space free of particles). They do not depend on particles of matter.
o Light is an electromagnetic wave.Light from the sun can travel to the Earth through the vacuum of space. Light can also travel through air across your room. Although you might not realize it, you are constantly surrounded by thousands of electromagnetic waves everyday. Sunlight (visible light) and X-rays are only two types of electromagnetic waves. Other types are radio waves, infrared rays, ultraviolet rays, and gamma rays.
Here is a helpful link for more information on light waves:http://junior.apk.net/~matto/notes(3).htm