Stage 3 – STEM Activity 12
Can we have quiet please?
Description of activity
How can I stop the noise transferring from my room and affecting others? Students evaluate the most effective sound insulator in order to build a room that minimises noise to its external neighbours.
This activity takes approximately 2 hours to:
- design and construct the room
- conduct the experiment and record the results.
It is advisable for students to work in groups of 2 or 3.
Context
The city of Sydney is a fast-developing urban centre. Land is at a premium and the cost of purchasing a home has resulted in smaller properties. People are living closer to their neighbours than ever before. Noise has become a priority for the building community. As an engineer/scientist you have been asked to design and develop the most effective noise-insulated room possible. You will need to reduce the number of decibels (volume) coming out of the room. The results will need to be graphed and recorded as a percentage in the reduction of noise. Cost is a factor, so select materials that are within the budget. You will need to build a room and test three different materials. Place a small portable speaker inside the room for testing and the monitor on the outside for recording the decibels.
Outcomes
Skills
ST3-4WS investigates by posing questions, including testable questions, making predictions and gathering data to draw evidence-based conclusions and develop explanations
ST3-5WT plans and implements a design process, selecting a range of tools, equipment, materials and techniques to produce solutions that address the design criteria and identified constraints
MA3-1WM describes and represents mathematical situations in a variety of ways using mathematical terminology and some conventions
MA3-2WM selects and applies appropriate problem-solving strategies, including the use of digital technologies, in undertaking investigations
MA3-3WM gives a valid reason for supporting one possible solution over another
Knowledge and understanding
ST3-13MW describes how the properties of materials determine their use for specific purposes
ST3-14BE describes systems in built environments and how social and environmental factors influence their design
ST3-15I describes how social influences impact on the design and use of information and communication systems
ST3-16P describes systems used to produce or manufacture products, and the social and environmental influences on product design
MA3-7NA compares, orders and calculates with fractions, decimals and percentages
MA3-11MG selects and uses the appropriate unit to estimate, measure and calculate volumes and capacities, and converts between units of capacity
MA3-14MG identifies three-dimensional objects, including prisms and pyramids, on the basis of their properties, and visualises, sketches and constructs them given drawings of different views
MA3-18SP uses appropriate methods to collect data and constructs, interprets and evaluates data displays, including dot plots, line graphs and two-way tables
Resources
- Materials for insulation, eg aluminium foil, cloth, foam, carpet, isolation foam, polystyrene
- Cardboard or boxes to make three rooms, glue, Velcro dots to attach the materials to the wall
- Portable speaker or device to generate a consistent sound, eg alarm clock or ‘ding’ sound produced from a digital device
- IPhone or device with any free app to measure volume.
Work, health and safety
- Check relevant Work, health and safety guidelines.
- Some students may be particularly sensitive to specific sounds, they may require ear protection.
Evidence of work for assessment purposes
- labelled diagram showing the shape and dimensions of the room and justifications for the choice of lining materials
- photos of the constructed rooms
- experimental report showing the method, results of testing shown in tabular and graphical forms and student’s findings
STEM teaching and learning activities
- Explain the context of this investigation to students, highlighting the concept of noise pollution, the social responsibility to keep it at a reasonable level and the ability to easily and accurately measure sound levels.
- Students discuss the properties of materials that might make them good insulators of sound.
- Students recall the characteristics of a fair test as they will be applied to this investigation.
- Students plan an investigation that will determine which type of insulation will prevent/reduce the volume of sound detected outside a room.
- In their experimental design, students must address various issues by answering the following questions:
- What factor am I changing?
- How can I change that factor?
- What am I measuring to see the effect of that change?
- How can I measure it?
- Which factors need to be constant, in order to make this a fair test?
- How can I make sure they are constant?
- How can I make sure my results are reliable?
- Students will need to:
- create a consistent sound that has a fixed volume and can be repeated
- measure the volume of the sound in decibels (dB)
- construct spaces/rooms of equal size, shape and volume.
- Students develop their design plans to construct their testing rooms. Students ensure that the rooms are the same shape and contain the same volume.
- Students construct the rooms, carry out their investigation as planned and gather results in a table like this:
- Students present their results in the form of tables and associated graphs so that these results can be analysed.
- Which insulating material is the most effective?
- By what percentage is the noise level reduced?
- Students discuss their findings with the rest of the class focusing on issues such as:
- Did everyone find that the same insulating material was the most effective?
- If not, what reasons could account for the differences?
- How might this investigation be improved?
- What are the properties of effective insulating materials?
Vocabulary list
Data – facts or figures that can be used to draw conclusions
Decibel – is used to measure loudness (dB)
Fair Test – an investigation where one variable (the independent variable) is changed and all other conditions (controlled variables) are kept the same; what is measured or observed is referred to as the dependent variable
First-hand investigation – an inquiry based on the direct use of observation or measurement
Insulator – a material or object that does not easily allow heat, electricity, light or sound to pass through it
Loudness – the perception of the amount of sound energy
Material – the matter from which something is made, eg fabric, metal, wood
Noise – a sound that is loud or unpleasant or that causes a disturbance
Property – a quality or characteristic of something (not a possession or house). Words used to identify properties: flexible, inflexible, elastic, protective, waterproof, shiny
Key inquiry questions
Fair testing is the basis of the scientific process. The ability to design, plan and test a hypothesis or solve a problem is integral to all studies in science and technology.
How will you choose the experimental variables?
Experiments are done in order to find cause-and-effect relationships. In other words, experiments are designed to test whether a change in one factor causes something else to change in a predictable way. These changing quantities are called ‘variables’. There are three types of variables:
- Independent: the factor (only one) that you choose to change in order to see whether that change has an effect
- Dependent: the factor that allows you to see whether the change has had a measurable effect
- Controlled: there would generally be several factors that must remain constant. These constant conditions help ensure that it is only the independent variable that causes any change. The maintenance of controlled variables makes an experiment a ‘fair test’.
What makes this a fair test?
In order to compare the results of one trial with another, the only factor that should be changed is the one being tested, ie the independent variable. The more variables that are controlled effectively, the more likely it is that any observed change is caused by the changes in the independent variable, and not something else.
Does it matter where you place the sound generator and the sound meter?
It is not so important where these things are placed, but their relative positions are important, eg the sound generator can be placed anywhere in the ‘room’ so long as it is placed in the same position for every trial. Similarly the sound meter can be placed anywhere outside the ‘room’ so long as it is placed in the same position for each trial. These are important controlled variables.
How much data will you collect?
In any collection of experimental data it is important to take a number of readings/do a number of trials, and then take the average of these readings. This reduces the effect of a ‘fluke’ result and thus increases the reliability of the data. Sometimes this can be achieved by having every group follow exactly the same method and then combining results. By allocating roles to group members and swapping the roles so that each group member does each task at least once, a number of trials are performed and results can be combined.
Additional information
The following statements outline some common preconceived ideas that many students hold, which are scientifically inaccurate and may impede student understanding.
My experiment failed
It is unusual to achieve perfect results on the first try. Repeat attempts and modifications are encouraged and failures considered. It is through the failures and resulting modifications that students learn. Keeping note of these modifications and the reasons for them creates a useful learning tool.
The thicker or more dense the material to insulate the more it will reduce external noise
Sound is a type of energy that is produced when things vibrate (thus it is a form of kinetic energy). If we are to stop sound from travelling, we need to stop the vibrations caused by sound. Often sound travels better through more dense materials because the particles in those materials are able to hit one another and transmit sound. For example sound travels longer distances through water than air. The particles in water are closer together (ie it is more dense) than in air. When some particles vibrate, those close to them also vibrate and thus the sound is transmitted. In air, particles are far apart so the sound will not be able to travel as far.
Support materials
Teacher resources
- YouTube video: Scientific Variables
- Designing and running a fair test: assessment rubric
- Working Scientifically: Investigation Framework
- Many free apps are available to measure noise levels
Student resources
- YouTube video: What is sound?
- YouTube video: How sound travels through different media
Diversity of learners
For extension
- Students research how people with hearing loss manage in our environment, eg how could Beethoven keep composing music after he became deaf.
- Does the design of the room (shape or size) affect the noise level? For example, keep the shape of the room the same but change the volume of the room, or keep the volume of the room the same but change the shape from a square to a rectangle or hexagon.
- Move the measuring device away from the source of the sound by regular increments and measure the decibel level. Record the data in an appropriate table. Design an algebraic equation to reflect this relationship.
Review
By completing this STEM activity you have provided your students with the opportunity to plan and carry out an investigation, gather data and draw conclusions based on that data. Students have explored the characteristics of sound energy and properties of insulators.
Students have carried out a design plan and built the equipment used in the investigation. This process of design is more fully developed in Technology (Mandatory) Stage 4.
NSW Government