Sound Energy and Waves

• At the end of a 60 minute period, 75% of the students can discuss what a sound wave is, give examples, and relate sound waves to real-world applications.

Sound Energy and Waves

• Sound travels on a longitudinal wave.
• Sound travels in a spiral form.
• When dropping a stone into a pool of water, the way waves move across the water is similar to how sound waves travel through the air.
• When speaking or shouting, vocal chords vibrate which travel in all directions through the air as waves.
• When the waves reach ears, they cause the eardrums to vibrate, allowing hearing.

Types of Waves

• Longitudinal wave: Vibration of particles in the medium is parallel to the direction of propagation.
• Transverse wave: Vibration of particles in the medium is at right angles to the direction of propagation.

Sound Transmission Mediums

• Sound waves travel on a medium.
• Sound waves can travel though any solid, liquid or gas.
• Sound travels by pushing the particles of a substance.
• The particles push into their neighbor, then return to their original position.
• Sound continues to travel in this way until it reaches the ear.
• Sound travels through a solid faster than through a liquid, which is faster than through a gas.
• Ears are designed to hear sound through a gas.

Compressions and Rarefactions

• Compressions constitute the area of sound waves where molecules are closer together.
• Rarefaction is the area of sound where molecules are further apart.

Wavelength and Frequency

• Wavelength is the distance from the end of one compression to the end of the next.
• Frequency is the number of waves produced per second.
• Frequency refers to "how often" air particles vibrate.

Pitch

• Pitch is defined as the rate at which vibrations are produced.
• The higher the frequency, the higher the pitch.
• The more waves per second or the higher the frequency the higher the pitch.

Intensity

• Intensity depends on the strength, also known as the amplitude, of the vibrations producing the sound.
• Stronger vibrations compress the molecules of the air more forcefully giving them greater energy.
• Stronger vibrations are interpreted by ears as a louder sound.

Wave Properties and Scenarios

• Medium for sound transmission.
• Sound travels better through a solid medium, than a liquid medium.
• Sound waves are made up of compressions and rarefactions.
• Compressions represent areas where molecules are closer together.
• Rarefaction is where molecules are further apart.
• Wavelength is the distance from one compression to the beginning of the next.
• The greater the frequency results in a larger range with variations.
• The speed of a wave is unaffected by changes in the frequency.
• If jet is closer, there's higher pitch and when further away, lower pitch.
• The closer the jet, the more intensity, thus, the louder the jet sounds.