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Sound. How are sounds made?. Waves. Sounds move in waves. A wave is a change that carries energy from one place to another. Sound is a form of energy that travels as waves through matter. Waves. Distance between one crest or trough. High Point. Frequency. amplitude. Low Point. Waves.
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Sound How are sounds made?
Waves • Sounds move in waves. • A wave is a change that carries energy from one place to another. • Sound is a form of energy that travels as waves through matter.
Waves Distance between one crest or trough High Point Frequency amplitude Low Point
Waves • Two types of waves: • Longitudinal waves • particles move back and forth in the same direction like a spring. • This is how sound waves travel • Sound can pass through matter • Transverse waves • particles move in a different direction than the wave this like ocean waves.
How Sounds Are Made • Sounds are made when something vibrates. • Vibrate is to move back and forth quickly.
Studying Waves crest Trough
How You Hear Sound Message is sent to Brain Vibrates Catches sound waves Passes vibrations to the inner ear
Summarize • Sound is a form of energy that travels in waves. • Sound is produced when matter vibrates or moves back and forth quickly.
Sound How can sound be changed?
Properties of Sound • Sound cannot travel in empty space. • Sound can only travel through matter. • The matter is called the medium of sound. • Solid • Liquid • Gas • Sound waves travel at different speeds depending on the medium through which the wave is traveling. • Sound waves move faster through warm mediums. • Sound moves slower through cold mediums.
Pitch • The pitch of a sound is how high or low it is. • The pitch is caused by the frequency of the sound wave. • High frequency = High pitch • Low frequency = Low pitch
Volume • Volume is how loud or soft a sound is. • Volume depends on how much energy a sound wave has. • The amplitude shows a sounds wave’s energy. • He higher the amplitude the louder the sound. • The higher the crest the higher the amplitude.
Controlling Sounds • Volume is measured in decibels. • Loud sounds can hurt your ears and damage your hearing if the sound is greater than 85 decibels. • Large airplanes and some tools like jackhammers are very loud. • People who work around these things use earplugs to protect their ears.
Acoustics • Acoustics is the study of how sounds travel and can be controlled. • Good acoustics helps people hear sounds clearly. • Sound waves bounce off or reflect off certain surfaces such has hard surfaces. • Sound waves also can be absorbed by certain surfaces such as soft surfaces.
Summarize • The pitch and volume of a sound can be changed by controlling the traits of a sound wave.
Stump the Teacher! • This week we learned how sounds are made and how sound can be changed. • Read back over lesson 1 and 2 on pages 112- 129. • Write down 5 questions to stump the teacher along with your answers. • The question and answers must come from the content from the reading material assigned. • You must prove your answer if you think the teacher has been stumped. • If the teacher gets the question right the teacher gets a point. • If the teacher is stumped then the students get a point.
Review • A boy is plucking a stretched rubber band to make sounds. How can he change the pitch? • Stretch the rubber band more or less tightly. • How are light and sound ALIKE? • Both are forms of energy that travel as waves. • What does the frequency of sound wave determine? • Pitch • What does the amplitude of a sound wave determine? • Volume
Review • What is the distance between crests and troughs called? • Wave length • What unit is volume measured in? • Decibels • What medium does sound travel through the fastest? • Solids
Review • The number of troughs of sound waves that pass every second measures what property of sound? • Frequency • Explain how a guitar produces sound • When the string is plucked, air particles vibrate. • What happens when a violin string is plucked? • The string vibrates causing sound waves.
Review • Explain why Mr. Blakely’s voice is pitched lower than Walter’s voice. • Mr. Blakely’s voice vibrates at a lower frequency than Walter’s. • Explain how we hear with our ears. • Our outer ear gathers sound waves. • You place the tips of a vibrating tuning fork into a dish of water. What does this show? • Sound travels as waves in vibrating matter.
Review • Which part of the ear passes vibrations to the middle ear? • Eardrum • A trumpet and a tube are blown with the same amount of effort. Why do they sound different? • They produce different pitches. • The amplitude of a sound wave is a measure of • How pushed together or spread apart the particles are.