SOUND Science
What Makes Sound? vibration – a back and forth movement energy transfer
How Does Sound Travel? Sound is a vibration that travels through matter. As vibration occurs, molecules in the air squeeze together and then spread apart. compression – the part of sound wave where molecules are crowded together rarefaction – the part of the sound wave where molecules are spread apart
Sound waves travel as compressional waves.
Sound waves can only travel through matter. Sound waves need PARTICLES to travel. Sound waves can only travel through matter. Gases, liquids or solids
How Can You Change a Sound? pitch – how high or low a sound is Higher pitched sounds will have a greater frequency of sound waves. frequency – the number of times an object vibrates per second hertz – a unit for measuring frequency
Looking at amplitude Amplitude measures how much energy is in the wave. Big amplitude = BIG SOUND
The pitch depends on how many vibrations there are. The more frequent the vibrations the higher the note. The fewer the vibrations the lower the note
What Makes Sound Loud? Energy of Sound Waves Decibels – a unit for measuring loudness
Loudness Amplitude determines loudness. An amplifier increases the amplitude of sounds.
Do Sounds Bounce? reflection – the bouncing of a sound wave off a surface Example – the crack of the baseball bat absorption – the disappearance of a sound wave into a surface Example – the sound of a baseball hitting the glove
What Is An Echo? echo – a reflected sound wave
Ultrasound and Sonar Sonar is a system that uses reflected sound waves for measurement and can measure large distances.