Sound+Energy



What is sound? Sound is type of energy made by vibrations. When any object vibrates. It causes movement in the air particles.These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy. If your ear is within range of the vibrations, you hear the sound.

Picture a stone thrown into a still body of water. The rings of waves expand indefinitely (not definite). The same is true with sound. Irregular repeating sound waves create noise, while regular repeating sound waves produce musical notes.

When the vibrations are fast, you hear a high note. When the vibrations are slow, it creates a low note.  Sound Facts!! Sound travels through the air at 1,120 feet (340 metres) per second. ​ __Can sound travel under the water?__ Yes soun can travel under the water, It moves four timrs faster through the water than air. It can travel such long distances that whales can hear each other when they are nearly a hundred miles apart! __Is there sound on the moon?__ No, there is no sound in space. Sound needs something to travel through like air or water.

__How do woodwind instruments make sound?__ In wind instruments, like flute and trumpet, vibrating air makes the sound. The air particles move back and forth creating sound waves. Blowing across a flute's blow hole sets up Slinky-like waves in the tube. In the clarinet, a vibrating reed (a thin piece of wood set in the mouthpiece) gets the waves started. Different pitches are played by pressing keys that open or close holes in the tube making the air column inside the tube longer or shorter. Longer air columns produce lower pitches.

__How do string instruments make sound?__ Stringed instruments are played by pressing the fingers down on the strings. This pressure changes the strings' length, causing them to vibrate at different frequencies and making different sounds. Shortening a string makes it sound higher. Strings produce different sounds depending on their thickness.

**Sound is a form of energy** Use a toy slinky, Stretch it out between two students One student should grab several coils on the slinky. Then let go. You will see the group of coils go across to the other student. Then come back to the starting student. Make sure you notice how the coils stay together. This is what sound waves do. Use a slinky toy. Stretch it out between two students. One student should grab several coils on slinky. Then let go. You will see the group of coils go across to the other student. Then come back to the starting student. Make sure you notice how the coils stay together. This is what sound waves do.
 * Sound waves are compression waves**

**Echo** Not all sound that hits matter is absorbed. Some of it is reflected. That means sound bounces off the solid matter the way a tennis ball bounces off a wall. Sound reflected back to its source is an echo. When sound strikes soft materials, much of the sound is absorbed. A sound insulator is a material that absorbs most of the energy of sound waves. An object like a violin vibrates the air, and those vibrations travel from the violin through the air until they reach us. But we don't hear a violin with our noses or elbows! These vibrations need to travel into our ears for us to really hear them. Well, the ear is naturally designed to collect, focus, and transmit sounds through a tine and efficient conveyence system called the audiotory pathway. Sound vibrations, or sound waves, are collected by the outer ear (those are the things hanging on the sides of your head!) and travel into the ear canal, where they bump up against the eardrum. The ear drum vibrates in sympathy with these sound waves. As it vibrates, it moves a series of tiny bones in the middle of the ear, which carry the vibrations to a fluid-filled tube called the cochlea in the inner ear. The fluid inside the cochlea vibrates a series of tiny hairs called cilia, which are attached to the auditory nerves. The movement of these cilia stimulates the nerves, and they send signals to the barin, which, inturn, processes these signals into the sounds we hear.
 * What happens when we hear a sound?**
 * __So what is so special about our ears that allow us to hear sound?__**

You can see a picture of a sound wave on the screen of a device called an __oscilloscope__.
===Look at the diagram above. The __compressions__, in which particles are crowded together, appear as upward curves in the line. The __rarefactions__, in which particles are spread apart, appear as downward curves in the line. === Three characteristics are used to describe a sound wave. These are wavelength, frequency, and amplitude.


 * __Wavelength__; this is the distance from the crest of one wave to the crest of the next.
 * __Frequency__; this is the number of waves that pass a point in each second.
 * <span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">__Amplitude__; this is the measure of the amount of energy in a sound wave.


 * ===<span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">__Pitch__ ===

<span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">This is how high or low a sound seems. A bird makes a high pitch. A lion makes a low pitch.
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<span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">The more energy the sound wave has the louder the sound seems. The intensity of a sound is the amount of energy it has. You hear intensity as loudness. <span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">Remember the amplitude, or height of a sound wave is a measure of the amount of energy in the wave. so the greater the intensity of a sound, the greater the amplitude. ||  ||
 * ===<span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">Sounds also are different in how loud and how soft they are. ===

<span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">Some sounds are pleasant and some are a noise. <span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">Compare the two waves on the right. <span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">A pleasant sound has a regular wave pattern. The pattern is repeated over and over. But the waves of noise are irregular. They do not have a repeated pattern. ||  ||
 * ===<span style="background-color: #c0c0c0; font-family: 'Comic Sans MS',cursive;">Pitch and loudness are two ways that sounds are different. Another way is in quality. ===

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