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Modern School Acoustics      On teaching styles, room acoustics, teachers      health and pupil behaviour
Modern School Acoustics on teaching styles,                                        room acoustics, teachers’ health and pu...
The third stage then addressed how                        2. Teaching past andnoise, in terms of natural, working         ...
in the classroom in comparison           The methods chosen are generallywith those produced by traditional,      dependen...
intelligibility is to be achieved.       the teachers voice is transmittedSince an adult voice is designed for     from on...
4. "Acoustic Ergonomics" –               contrary, under optimum conditions    Share of "quiet" teaching phases (overall) ...
Pupil-centred teaching phases are frequently quieter under                          The rise of the basic SPL over the mor...
After acoustic refurbishment, the teacher works with a                                  5. Consequences and               ...
The proud team of "scientific staff" after successfully measuring the acoustics of their classroom.                       ...
Classroom solutionRecommendation for normal sized classrooms(area: <100m², volume: <200m³, length: <9m)                   ...
GlossaryAcousticsThe study of sound. In everyday language also refers to how sound isperceived in particular premises.Reve...
Complaints about noise pollution in educational premises were the                        reason to cast a light on causes ...
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Acoustic Ergonomics of Schools research report by Bremen University, Germany.

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The study centred on the “school as a workplace” and as such the workplace of teachers and pupils. The study shows the link between a reduction in noise and the reduction in teachers stress levels. It also demonstrates that sound level reduction in the occupied room is more dramatic with multi conversation activities such as groupwork.

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Transcript of "Acoustic Ergonomics of Schools research report by Bremen University, Germany."

  1. 1. Modern School Acoustics On teaching styles, room acoustics, teachers health and pupil behaviour
  2. 2. Modern School Acoustics on teaching styles, room acoustics, teachers’ health and pupil behaviour By Dr. Markus Oberdörster, Ecophon Germany and Dr. Gerhart Tiesler, Institut für Interdisziplinäre Schulforschung der Universität Bremen (Institute for interdisciplinary school research of the University of Bremen, Germany)1. Noise in schools – current by pupil noise. One year later, the Of course, the sound pressure level performance and/or teachers workstatus of school research Bundesanstalt für Arbeitsschutz und measured in the classroom does stress? And, not least, what areSchools have become much noisier Arbeitsmedizin (German Federal not only consist of unwanted noise, teachers really talking about whenin recent years, with the number Institute of Occupational Health) since the teachers voice and a they complain about noise in theof complaints about this steadily was commissioned to carry out necessary contribution of pupil classroom – the measurable SPLincreasing. In 1999, a study by the most extensive research project voices are also involved. Thus, or, rather, the way in which theirthe ISF (Institute for Interdisciplinary to date on "Noise in educational overall classroom noise is generated teaching is disturbed?School Research) of the University establishments". Observations from by the two-way teaching process All these issues resulted in theof Bremen, with about 1,200 more than 570 lessons showed as well as by other factors. Even most recent ISF study in 2005teachers participating, gave a very an average classroom SPL (sound if this overall level were generated on the "Acoustic ergonomics ofclear picture of the stress factors that pressure level) of approximately exclusively by the teacher, this schools". Based on 175 lessons,arise in schools. When questioned, 65 dB(A). Levels that are this would mean - at the very least - that the first stage involved researchingmore than 80% of those taking part high mean that communication he or she would have to speak in the effects of different teachingadmitted experiencing stress caused can be extremely difficult or even a raised voice throughout the entire methods (direct teaching vs. impossible. lesson. student-centred teaching) on the The question of noise in schools basic* and working** SPL in"I am stressed Answers (%) is therefore extremely complex. the classroom. The second stageby the noise 50 How, for instance, does the general involved an investigation intothat pupils noise level in the classroom affect how changing room acousticsmake." 40 the communication processes (reverberation time and speech that take place there? How it is intelligibility) affects this level for 30 possible to differentiate between each respective teaching method. disturbing noise on the one hand It was possible not only to analyse 20 and useful noise (sound) on the average values for lessons but other hand, when carrying out a also to gain insight into actualISF study, 1999: 80%of teachers complain 10 scientific teaching analysis? How teaching phases that showed clear,about the noise made do SPL and poor understanding pedagogical characteristics.by pupils 0 of communication affect pupil do not agree tend not to agree totally agree at all agree slightly *The Basic SPL: the general basic noise level in a fully occupied class over a defined time period. ** The Working SPL: the noise level parameter describing a working situation.2
  3. 3. The third stage then addressed how 2. Teaching past andnoise, in terms of natural, working present - schooling reflectedsounds, affects teachers during in educational trendslessons. How do room acoustics The education system in mostaffect teachers measurable industrialised countries is changingphysiological stress in relation to faster than ever before, not justactual teaching events? since recent OECD-Reports1). These kinds of ergonomic The organisation of schooling inquestions, linked with actual general, and teaching methods ineducational trends, may be particular, have changed a lot in School with predominantly student-centred teaching method.surprising at first glance. However, recent years.they give an interesting insight into Is noise in schools a newthe concept of noise in schools, problem, one that did not existits causes and effects, and into previously? This question is certainlyother acoustic factors such as justified, since complaints byreverberation time and speech teachers about noise do not occurintelligibility. in the literature from the beginning of the 1900s. The "modern", "student-centred" and "non teacher- centred" teaching methods (e. g. partner, group or project work) that are promoted by educational experts do certainly produce totally different communication scenarios1) OECD (Organisation for Economic Co-operation and Development)/PISA (Programme for International StudentAssessment, Learning for Tomorrows World, First Results from PISA 2003, OECD Publishing, Dec 2004, 478 p,ISBN: 9264007245. (Available in English, German, French, Portuguese and Spanish) OECD/Centre for Educational Research and Innovation (CERI), Schooling for Tomorrow: Think Scenarios, RethinkEducation, OECD Publishing, April 2006, 200 p, ISBN: 926402364X (Available in English and French) School with predominantly direct teaching method. 3
  4. 4. in the classroom in comparison The methods chosen are generallywith those produced by traditional, dependent on the personaldirect teaching. The image of the preferences of the teaching staffteacher as a distributor of material, and on the prevailing teachinga channel of knowledge, is fading. style at the school in question. The presence of technology was only unfamiliar for a short time. After just a fewPupils now have to independently The layout of the classroom and hours, children saw the measuring instruments and loudspeakers as just anotherinvestigate, weigh up, discuss the arrangement of the desks are part of normal classroom equipment.and acquire the knowledge and sometimes relevant, since theseskills to solve the problems they indicate the teaching methodsare presented with. Modern that are used to determine whatteaching relies much more on happens in the classroom. 3. The peculiarities of noise around 65 dB(A) must be rated asshared learning, and deliberately Shortsighted analyses, which in schools a useful or wanted signal, generalpermits several people to talk in have attributed the much higher When discussing noise in relation pupil murmur of around 55 dB(A)the classroom at the same time. noise levels in recent decades to education and schools, its quality during a quiet working period mightEven in a disciplined discussion exclusively to social or educational and quantity are very different be rated as noise interference. Aenvironment, however, higher noise trends, fall far short of the truth. from that of the noise occurring in straightforward increase in the noiselevels than before occur, when Even early investigations proved commercial workplaces, be it an level in a classroom, without takingteachers used to lecture the class the relationship between a rooms industrial or an office environment. the actual teaching situation intoas a whole. This is particularly the acoustic working environment, While the noise produced by consideration, is only a small partcase when the teacher exercises a the quality of communication and machinery is generally felt to be of the noise in schools concept.high level of discipline. the development of noise in the noise interference, the noise level A first, decisive criterion for Nowadays we tend to find a classroom. It is therefore important in educational environments should appraising noise in schoolsmix of direct and student-centred to ask: What are the determining be regarded as a useful signal is the ratio of “useful signal”teaching styles in the classroom (key factors for teaching in respect of with a widely varying degree of to “interference signal” in thephrase "frontal teaching discussion"). modern, educational methods? interference factor. Its differentiation classroom, taking into account the and evaluation depend on the communication processes in the teaching method being used in lesson. For an adult, the useful the case in question. For example, signal must generally be around while text being read out in a 9 dB higher than the interference voice with a speech volume of signal if error-free speech4
  5. 5. intelligibility is to be achieved. the teachers voice is transmittedSince an adult voice is designed for from only one point and –a normal speech volume of around depending on the size of the room50 to 55 dB(A), this means that and the position of the teacherthe noise interference level must be - may need to travel over a distance In more than 570 lessons, as well as the SPL being measured, the activities inless than 40 dB(A). Even in quiet of up to 6 m to reach pupils sitting the classroom such as teaching methods or proportion of speech were recordedwork periods, however, the SPL in at the back. If the basic noise is every second.schools seldom measured under 50 unchanged, this involves eitherdB(A), i.e. teachers usually have to a distinct additional strain on theraise their voices in order to pass teachers voice, leading to longinformation on to the pupils. In term health consequences, or an will compensate for the pooreraddition, specialist literature points interrupted flow of information to speech intelligibility in their groupsout that primary-school children pupils sitting further away, resulting by raising their voices, which inneed to specifically learn how to in negative effects on their learning. turn increases the noise interferencelisten and understand before they There is another aspect to level for the others, and so on.can develop their as yet untrained consider in relation to modern, The noise level in the classroomacoustic memory. Young hearers student-centred teaching methods. If therefore gradually increases eventherefore need a useful signal level there are several groups speaking if the number of people actuallythat is about 15 dB louder than in the room at the same time, the communicating remains the same.the ambient noise interference. An signal from one group becomes This is known in acoustic circles asadded difficulty is the fact that the noise interference for the other the Lombard effect.noise interference in a classroom is groups. This results in a negativerelatively evenly distributed, while chain reaction. The other groups 5
  6. 6. 4. "Acoustic Ergonomics" – contrary, under optimum conditions Share of "quiet" teaching phases (overall) in classrooms withnoise in schools and the noise level measured during good/poor acoustics.teachers health student-centred teaching phases Share of time (%)Room acoustics are particularly was even lower than during direct 80significant with regard to modern teaching. 70teaching. For instance, short Overall, the basic SPL inreverberation times result in a classrooms with reverberation times 60precise speech signal (especially of less than 0.5 seconds were 8 50in respect of consonants), and dB lower than in classrooms with 40people can communicate with a reverberation times of between 0.6lower signal-to-noise ratio. The study and 0.8 seconds. 30Acoustic Ergonomics in Schools 20(2005) showed that the build-up 10of noise is considerably less, ordoes not occur at all, in classrooms 0 Reverberation time > 0.5 sec. Reverberation time < 0.5 sec.that have good acoustics. On the Under better acoustic conditions, the proportion of "quiet" teaching units was more than 80% compared to approximately 67% under poorer conditions (in relation to the average speech volume of an adult - approx. 62 dB(A) - taken as normal teaching speech).6
  7. 7. Pupil-centred teaching phases are frequently quieter under The rise of the basic SPL over the morning is much less ingood acoustic conditions. rooms with short reverberation times.Share of time (%) LA95 [dB(A)] 80 70 70 60 65 50 60 40 30 55 20 10 50 0 Reverberation time > 0.5 sec. Reverberation time < 0.5 sec. 45Even more obvious is the change in classroom conditions during student-centred 40teaching phases. In this case the proportion of quiet time units doubles! Thisclearly indicates an absence of the Lombard effect during partner, group orproject work. The difference in levels between rooms with good acoustics and 35those with poor acoustics while these teaching methods were used was morethan 13 dB! 30 1 2 3 4 5 Lessons An additional, important aspect was revealed by this comparison of teaching situations. The normal increase in the basic noise level over the course of the school day did not occur in the classrooms with short reverberation times (< 0.5 seconds). This has a significant effect on the teaching process and provides an initial indication of the physiological reactions that take place as a result of the acoustic working environment. 7
  8. 8. After acoustic refurbishment, the teacher works with a 5. Consequences and schools. The relationships wererelaxed heart rate for more than 80% of the time compared outlook easily identifiable. Only the schoolsto just 60% before refurbishment. With a change in educational where the staff followed a common,Share of time (%) approaches, a steady increase in accepted educational concept were student-centred teaching methods really quiet. In schools where the100 and a corresponding reduction in same rules apply in all classrooms, direct teaching, it may be necessary during all lessons and in all the 90 to re-evaluate school buildings that different areas of the school, and have functioned well for many where the children can expect the 80 years. New teaching methods same teacher reaction if they do not place new demands on the basic comply with those rules, the noise 70 ergonomic conditions. levels measured over a long period It would be absurd to claim were lower. The recipe is therefore 60 that teachers themselves have as simple as it is effective. The only no influence on noise in their requirement is that staff work as a 50 classrooms. They do, of course team and are consistent. Reverberation time > 0.5 sec. Reverberation time < 0.5 sec. – and it is important that they The school organisation andThe positive effects of good room acoustics also reduce the teachers stress level. exert this influence. This issue is the personal contributions ofAfter an acoustic refurbishment, the same teacher was subject to comparatively addressed in depth in the research individual teachers are essentiallittle work stress for a much greater part of the lesson. Further investigations also report of the study "Noise in factors in effectively reducingshowed that the teacher was less sensitive to the stress-inducing noise, with educational establishments" (2004). noise in schools. The ergonomicwork thus becoming much more relaxed. It is undoubtedly true that there is an This study also showed the level conditions provide the necessaryergonomic dimension to the acoustic design of classrooms. It directly affects the reductions that can be expected foundation for the teaching activitieslevels of work stress, activation and fatigue of the people who teach (and learn) after fairly immediate intervention by of the school day. Neither of thein these premises. individual teachers: approximately two aspects can be replaced 2 dB. At the same time, however, nor offset by the other. They are in rooms with resembling acoustic mutually interdependent and need conditions and a comparable pupil to interact if the teaching process social structure, there was evidence in context of modern pedagogical of similar differences (5 to 6 dB) communication is to function in the noise levels of different properly.8
  9. 9. The proud team of "scientific staff" after successfully measuring the acoustics of their classroom. 9
  10. 10. Classroom solutionRecommendation for normal sized classrooms(area: <100m², volume: <200m³, length: <9m) Acoustic ceiling of sound absorption 1.1 - Classroom Solution class A (Ecophon Master) Wall absorber from 0.8 to 2.0 metres above the floor (Ecophon Wall Panel) 1.1 Classroom solution Reflector over the teachers desk area if enhanced speech comfort is needed (Ecophon Master/gamma) Additional wall absorber from 0.8 to 2.0 above the floor if there is a risk for flutter echo or if increased sound level reduction1.2 Classroom solution with low1.2 - Classroom Solution is needed (Ecophon Wall Panel)with low frequency absorberfrequency absorber Low frequency absorber (Ecophon Master Extra Bass)10
  11. 11. GlossaryAcousticsThe study of sound. In everyday language also refers to how sound isperceived in particular premises.Reverberation time, (T or RT)The time it takes for the sound pressure level to fall by 60 dB after thesound has been turned off. Measuring the reverberation time allows usto calculate the total sound absorption. The reverberation time variesaccording to the frequency.Sound pressure level (dB)The variations caused by sound waves in air are called sound pressure.The lowest sound pressure level which can be heard is 0 dB, known asthe hearing threshold. The highest level which can be tolerated is calledthe pain threshold and is around 120 dB.Speech intelligibilitySpeech intelligibility is directly dependent on the level of backgroundnoise, reverberation time and the shape of the room. Different methodsare used to evaluate speech intelligibility, the most common ones areRASTI, STI and %ALcons.Lombard effectThe Lombard effect is the tendency to increase ones vocal intensity innoise.© Ecophon Group 2006 11Idea and layout: Saint-Gobain Ecophon AB, Printer: Skånetryck AB, Photo: Saint-Gobain Ecophon GmbH, Illustrations: Condesign Infocom AB, Dr Gerhard Tiesler and Saint-Gobain Ecophon GmbH
  12. 12. Complaints about noise pollution in educational premises were the reason to cast a light on causes and consequences of “school noise”. This interdisciplinary study investigated various kinds of teaching/ learning styles and sound pressure levels in the classroom, and moreover, how improved room acoustic conditions affect sound levels together with teachers workload and fatigue. This publication is a complement to the book “Dont limit your senses” Sound and the Learning Environment, Saint-Gobain Ecophon, ISBN 91-974193-2-X published in 2002. 06.11 5000, Art no: 929050Saint-Gobain Ecophon AB, Box 500, S-260 61 Hyllinge, Sweden, phone +46 42 17 99 00, fax +46 42 22 59 29,e-mail: ecophon.export@ecophon.se, www.ecophon-international.com
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