Sound
by Justin Cheng
1. How sound is transmitted
1.1. Sound transmitted is through liquid and gas as longitudinal waves.In solids however,sound can be transmitted as either longitudinal or transverse waves.
1.2. Sound cannot travel through vacuum, as there is no matter in vacuum,thus there would no medium that sound can be transmitted through.
2. What is Sound?
2.1. It is a mechanical wave that is an oscillation of pressure transmitted through matter.
3. Speed of sound
3.1. The speed of sound is about 330 metres per second.However,it is a lot slower compared to the speed of light.
4. Echo
4.1. Sound waves can be reflected by large,hard surfaces such as buildings.If the reflected sound is heard as a separate sound after a period of silence,it is known as an echo.Echos are used in sonar to locate underwater objects.
5. Pitch and Loudness
5.1. Pitch is used to distinguish different sounds and is dependent on frequency.The higher the frequency,the higher the pitch.
5.2. Amplitude is determined by how much energy is put into the vibrating system.The greater the amplitude,the louder the sound.
6. Ultrasound
6.1. Ultrasound is a type of sound waves that have a frequency greater than 20 kHz.It is used in sonar and examining the internal tissues and organs of a patient.