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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD: 

Demonstrate knowledge of the physics of sound 
SAQA US ID UNIT STANDARD TITLE
252384  Demonstrate knowledge of the physics of sound 
ORIGINATOR
SGB Environmental Sc/Mgt & Waste Mgt 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 10 - Physical, Mathematical, Computer and Life Sciences Environmental Sciences 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 5  Level TBA: Pre-2009 was L5 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Reregistered  2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2024-06-30   2027-06-30  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard does not replace any other unit standard and is not replaced by any other unit standard. 

PURPOSE OF THE UNIT STANDARD 
This unit standard will be useful for people working in local authorities and charged with noise control, as appointed Noise Control Officers. They facilitate the generation of policy, develop procedures, apply the by-laws, ensure that issues between complainants and offenders are resolved, and initiate further action where this becomes necessary, including notices and legal proceedings.

More specifically this standard recognizes knowledge required to understand sound and its measurement.

People credited with this unit standard are able to:
  • Demonstrate knowledge of scientific principles of sound.
  • Demonstrate understanding of the speed of sound and implications for noise measurement.
  • Demonstrate understanding of noise measurement. 

  • LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
    The credit calculation is based on the assumption that learners are already competent in terms of the following outcomes or areas of learning when starting to learn towards this unit standard:
  • Competence equivalent to that described in the National Certificate: Environmental Noise, NQF Level 4. 

  • UNIT STANDARD RANGE 
    N/A 

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Demonstrate knowledge of scientific principles of sound. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The concept of particle velocity is used to explain the transmission of sound waves through a medium in accordance with accepted scientific principles. The explanation differentiates between particle velocity and the speed of sound. 

    ASSESSMENT CRITERION 2 
    Particle displacement or particle amplitude is explained in terms of its velocity and the oscillations of air molecules in a medium as it transmits a wave. The explanation is consistent with accepted scientific principles. 

    ASSESSMENT CRITERION 3 
    Measurement of particle velocity is explained with reference to the logarithmic decibel scale and the calculation of particle velocity levels. The significance of the resulting sound velocity level is explained with reference to noise measurement. 

    ASSESSMENT CRITERION 4 
    The concept of sound pressure is explained in terms of the pressure deviation from the local ambient pressure caused by a sound wave. The explanation includes reference to instantaneous and effective sound pressure, and their significance in the noise measurement. 

    ASSESSMENT CRITERION 5 
    The relationship between sound pressure and acoustic particle velocity in a sound wave is accurately explained in accordance with accepted scientific principles. 
    ASSESSMENT CRITERION RANGE 
    Relationship includes:
  • Complementary variable; linear (small amplitudes); acoustic impedance.
     

  • ASSESSMENT CRITERION 6 
    Acoustic impedance is explained with reference to the characteristics of the wave and the medium through which it travels, in accordance with accepted scientific principles. 

    ASSESSMENT CRITERION 7 
    The local instantaneous sound intensity is explained in terms of sound pressure and acoustic particle velocity. The explanation includes reference to vector quantity in time. 

    ASSESSMENT CRITERION 8 
    Sound pressure level (SPL) or Lp is accurately defined in scientific terms. Key concepts are used accurately in accordance with accepted scientific terminology. 
    ASSESSMENT CRITERION RANGE 
    Concepts include:
  • Root-mean-square sound pressure; reference sound pressure; ÁPa.
     

  • ASSESSMENT CRITERION 9 
    Scientific terms and concepts associated with sound and its measurement are used accurately, and explained correctly in accordance with generally accepted scientific usage. 
    ASSESSMENT CRITERION RANGE 
    Terms include:
  • Decibel, sone, mel, phon, hertz; Sound pressure level; Particle velocity, acoustic velocity, sound velocity; Particle displacement, particle amplitude, particle acceleration; Sound power, acoustic power, sound power level; Sound intensity, acoustic intensity, sound intensity level, sound energy density, sound energy flux; Acoustic impedance, sound impedance, characteristic impedance; Speed of sound, amplitude; Sound energy flux.
     

  • SPECIFIC OUTCOME 2 
    Demonstrate understanding of the speed of sound and implications for noise measurement. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    The speed of sound is described in terms of the relationship between the elastic modulus of the medium through which it travels and its density. 

    ASSESSMENT CRITERION 2 
    Speed of sound accurately calculated and expressed as a fundamental property of given materials. Reasons for the differences in speed are explained in accordance with generally accepted scientific understanding. 

    ASSESSMENT CRITERION 3 
    The impact of ambient conditions on the physical properties of materials and consequent effect on the speed of sound is correctly explained using examples of three different mediums. 
    ASSESSMENT CRITERION RANGE 
    Conditions include:
  • Temperature; atmospheric pressure; humidity and inversion layers; topography.
     

  • ASSESSMENT CRITERION 4 
    The effect of sound amplitude on the speed of sound is discussed with reference to nonlinear propagation effects, including the weak production of harmonics and the mixing of tones. 

    SPECIFIC OUTCOME 3 
    Demonstrate understanding of noise measurement. 

    ASSESSMENT CRITERIA
     

    ASSESSMENT CRITERION 1 
    Sound is discussed in terms of the key characteristics of power, mechanical energy and force. The operation of sound generating equipment is explained in terms of these characteristics. 

    ASSESSMENT CRITERION 2 
    The importance and use of the logarithmic decibel scales is explained with reference to the wide range of amplitudes detectable by the human ear. 

    ASSESSMENT CRITERION 3 
    Various logarithmic scales used in the measurement and/or description of sound are identified and described in terms of their purpose and application, in accordance with generally accepted scientific usage. 
    ASSESSMENT CRITERION RANGE 
    Scales include:
  • Sound intensity; pitch.
     

  • ASSESSMENT CRITERION 4 
    The relationship between the physical magnitudes of stimuli and the perceived intensity of the stimuli is accurately explained with reference to generally accepted scientific understanding. 
    ASSESSMENT CRITERION RANGE 
    Understanding includes:
  • Weber-Fechner law; quantitative approach to physical stimulus.
     

  • ASSESSMENT CRITERION 5 
    Sound pressure, sound intensity, sound power and sound energy density are differentiated in terms of what they describe, and their application in noise measurement. 

    ASSESSMENT CRITERION 6 
    The reason for frequency weighted sound pressure levels in the measurement of noise are explained with reference to the properties of the human ear, spectral response, and perceived sound pressure levels. 
    ASSESSMENT CRITERION RANGE 
    Weighting includes:
  • A-weighted sound pressure levels (dBA); C-weighting (peak levels).
     

  • ASSESSMENT CRITERION 7 
    Sound intensity is defined with reference to sound power and area, in accordance with generally accepted scientific usage. Its application in noise measurement is described with reference to sound intensity and the listener's location. 
    ASSESSMENT CRITERION RANGE 
    Usage includes:
  • Direction; magnitude; watts per square meter.
     

  • ASSESSMENT CRITERION 8 
    Sound intensity level, or acoustic intensity level, is explained in terms of the logarithmic measure of sound intensity against the accepted reference level of 0 dB. Its application in noise measurement is described, in accordance with generally accepted scientific usage. 

    ASSESSMENT CRITERION 9 
    Sound power, or acoustic power Pac, is described with reference to sonic energy, units of time, and scientific units of measurement. Its application in noise measurement is explained with reference to the sound source in comparison to a specified reference level. 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
    Accreditation Options:
  • Providers of learning towards this unit standard will need to meet the accreditation requirements of the relevant ETQA.

    Moderation Option:
  • The moderation requirements of the relevant ETQA must be met in order to award credit to learners for this unit standard. 

  • UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
    The following essential embedded knowledge will be assessed through assessment of the Specific Outcomes in terms of the stipulated Assessment Criteria. Candidates are unlikely to achieve all the Specific Outcomes, to the standards described in the Assessment Criteria, without knowledge of the listed embedded knowledge. This means that for the most part, the possession or lack of the knowledge can be directly inferred from the quality of the candidate's performance. Where direct assessment of knowledge is required, Assessment Criteria have been included in the body of the unit standard. 

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identify and solve problems and make decisions using critical and creative thinking.

    Note: Important in defining and identifying noise nuisances and disturbing noise. 

    UNIT STANDARD CCFO WORKING 
    Work effectively with others as members of a team, group, organisation or community.

    Note: Operates as a team leader, and must advise and resolve noise related issues. 

    UNIT STANDARD CCFO ORGANISING 
    Organise and manage themselves and their activities responsibly and effectively.

    Note: Recording information and presenting advice and information to others; as well as evaluating reports. 

    UNIT STANDARD CCFO COLLECTING 
    Collect, analyse, organise and critically evaluate information.

    Note: Key task is to evaluate the reports of others and validate these. 

    UNIT STANDARD CCFO COMMUNICATING 
    Communicate effectively, using visual, mathematical and/or language skills in the modes of oral and/or written presentations.

    Note: Core skill-communicating and mediating. 

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically showing responsibility towards the environment and health of others.

    Note: Understanding sound and noise measurement requires an ability to understand and use science and technology. 

    UNIT STANDARD CCFO DEMONSTRATING 
    Demonstrate an understanding of the world as a set of related systems by recognising that problem-solving contexts do not exist in isolation.

    Note: Core to role in noise management-understanding that the sounds people make affect those around them and may come to be viewed as unwanted sound, or noise. 

    UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    Notes to Assessors:

    Assessors should keep the following general principles in mind when designing and conducting assessments against this unit standard:
  • Focus the assessment activities on gathering evidence in terms of the main outcome expressed in the title to ensure assessment is integrated rather than fragmented. Remember we want to declare the person competent in terms of the title. Where assessment at title level is unmanageable, then focus assessment around each Specific Outcome, or groups of Specific Outcomes.
  • Make sure that evidence is gathered across the entire range, wherever it applies. Assessment activities should be as close to the real performance as possible, and where simulations or role-plays are used, there should be supporting evidence to show the candidate is able to perform in the real situation.
  • Do not focus the assessment activities on each assessment criterion. Rather make sure the assessment activities focus on outcomes and are sufficient to enable evidence to be gathered around all the Assessment Criteria.
  • The Assessment Criteria provide the specifications against which assessment judgements should be made. In most cases, knowledge can be inferred from the quality of the performances, but in other cases, knowledge and understanding will have to be tested through questioning techniques. Where this is required, there will be Assessment Criteria to specify the standard required.
  • The task of the assessor is to gather sufficient evidence, of the prescribed type and quality, as specified in this unit standard, that the candidate can achieve the outcomes again and again and again. This means assessors will have to judge how many repeat performances are required before they believe the performance is reproducible.
  • All assessments should be conducted in line with the following well documented principles of assessment: appropriateness, fairness, manageability, integration into work or learning, validity, direct, authentic, sufficient, systematic, open and consistent.

    Definition of Terms:

    Terms have been clarified as far as possible through the use of range statements. 

  • QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Fundamental  59325   National Certificate: Environmental Noise Control  Level 5  Level TBA: Pre-2009 was L5  Passed the End Date -
    Status was "Reregistered" 
    2015-06-30  LG SETA 
    Elective  80306   Further Education and Training Certificate: Electronics  Level 4  NQF Level 04  Reregistered  2021-06-30  As per Learning Programmes recorded against this Qual 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    1. Avenida (Pty) Ltd 
    2. Icando 
    3. Nyankwavi Investment CC. 



    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.