sound waves

• echos are used to measure speed of sound
• speed of sound through gas is very slow
• speed of sounds through liquid is higher than gas
• speed of sound through solids is faster than gas and liquids
• ultrasound waves can be used in finding the depth of water because the pulse sent when it hits any surface it is reflected back
• uses of ultrasound?

  industry (finding cracks in pipes), medicine, water depth and training dogs
• the speed of light is faster than the speed of sound