Grade 7 Sound Quiz: Waves and Properties

What is the primary factor that determines the pitch of a sound?

What happens to the amplitude of a sound wave when its frequency increases?

What is the characteristic of a sound that is perceived as loud or soft?

Which of the following best describes the relationship between the frequency and time period of a sound wave?

What is the minimum distance required for an echo to be heard clearly?

What happens to sound waves when they meet a soft surface?

What is the characteristic of a sound wave that determines its pitch?

What is the type of sound wave that is repeated because of reflection?

What is the relationship between the amplitude and loudness of a sound wave?

What is the term for the intensity of a sound wave?

Waves

A wave is a disturbance that travels through a medium, transporting energy from one place to another without transporting matter.

Types of Waves

Mechanical waves: require a medium to travel, e.g. water waves, sound waves
Electromagnetic waves: do not require a medium, e.g. light waves

Characteristics of Waves

Wavelength (λ): distance between two consecutive points on a wave that are in phase
Frequency (f): number of oscillations or cycles per second
Time period (T): time taken to complete one oscillation or cycle

Relationship between Frequency, Wavelength, and Time Period

Wavelength is inversely proportional to frequency (λ ∝ 1/f)
Frequency is inversely proportional to time period (f = 1/T)

Characteristics of Sound

Pitch: characteristic of sound that allows us to distinguish between shrill and grave sounds
Loudness: determined by the intensity of sound waves
Amplitude: increases as frequency decreases, and decreases as frequency increases

Sound Waves

Longitudinal wave: particles oscillate back and forth along the direction of the wave
Produced by vibrations, e.g. drumbeat, voice
Pitch increases with increase in frequency of vibration

Echo

Sound that is repeated because sound waves are reflected back
Occurs when sound waves bounce off smooth, hard objects
Echo is heard clearly when the reflecting surface is at least 17 meters away

Learn about the basic terms related to sound waves, including compression and rarefaction, and how they move through the air as a series of alternate high and low-pressure zones.