Task: 

Design, conduct and analyse a simple experiment to investigate the effect of distance from a sound source on its intensity or loudness. Use the sound intensity sensor in the Arduino Science Journal app (or similar) to measure sound intensity. 

Hypothesis:

(make a prediction about how the sound intensity will change with increased distance away from the sound source)

Method:

1.     Place your device (mobile phone) in a location suitable for recording sound intensity. (Think about its orientation and the position of the microphone)

2.     Hold your hands close to the device. Clap your hands 10 times, with a short break between each clap. (You should see clear spikes on the graph that correspond with your claps. Experiment with loud and soft claps to see how it changes the graph).

3.     Measure the distance between the device and the position where you clapped your hands.

4.     While recording, clap your hands 10 times again at the measured distance.

5.     Determine the highest decibel reading (highest peak) of the 10 claps.

6.     Record the maximum sound intensity (dB) for this measured distance in your results table.

7.     Repeat steps 3 to 6, doubling the distance from your device each time. (For example, clap at 0.25m, 0.5m, 1m, 2m, 4m and 8m)

Results: 

Use Microsoft Excel or similar to produce a line graph of these results and include a snip of your graph. When graphing the independent variable (distance from sound source) goes on the horizontal x axis. The dependent variable (maximum sound intensity) goes on the vertical y axis.

Discussion:

Use the guiding questions below to help you write a short discussion of your results.

• What happens to the measured maximum sound intensity as distance increased from the device? Was there a consistent trend? Was it a linear (straight line) relationship?

•  With greater distances, will the sound intensity ever reach zero?

• Does the loudness of the background noise affect the loudness of the maximum clap?

• What variables did you need to keep the same to make this a fair test?

• How could you improve the design of this investigation?

Conclusion:

What did you find out? Did your results support your hypothesis or not?

Have you ever been sitting in your room at home wondering how to block out traffic noise or loud music from outdoors? The sound waves produced outside travel through the air, hit the walls and windows and make these solid materials vibrate. Energy is transmitted through the solid glass, wood, concrete or stone and makes the air vibrate again on the other side and eventually these sound waves reach your ears. In this activity we investigate the effectiveness of different materials on reducing the transmission of sound energy. 

Task:

Design a simple experiment to investigate the effectiveness of different materials in blocking the transmission of sound. Use the sound intensity sensor in the Arduino Science Journal app (or similar) to measure changes in sound intensity. 

Imagine that you are going to design a soundproof room, or even a soundproof box. What design and materials would you use?

Brainstorm as many variables as you can that would affect sound absorption. Use Bubbl.us, an online mind-mapping tool to record your ideas (log in using their google account @education.nsw.gov.au), concept mapping or create your own brainstorming image.

Alternatively, discuss with your teacher whether a Padlet has been set up to complete this activity.

Once you have brainstormed different materials that could be used, identify all the materials that you would be able to use, collected from in and around the house, in your investigation.

Proposing a hypothesis

Think about the materials that you will be testing in your investigation. Make a prediction and try to rank the materials in order from the worst to the best material at reducing the transmission of sound.

Designing and planning

You now have some time to think about how you are going to design your investigation to answer the question:

What materials are best at reducing the transmission of sound energy?

You might like to think about features of fair testing, from the Fair test Lab.

• What variable will you change? (independent variable)

• What variable will you measure to see how it is affected? (dependent variable)

• What variables will you need to keep the same throughout the testing? (controlled variables)

• What materials will you need and what procedure will you use?

• How will you record and analyse the results?

Sample investigations that might give you some ideas are outlined in the Science Buddies activity Block that noise! and in TeachEngineering, What soundproofing material works best?

Don't forget to hand in the work you completed today!

• Your teacher will have told you to do one of the following: 

  • Upload any digital documents you created and any photos you took of your written work to your Learning Management system (MS Teams, Google Classroom for example).

  • Email any digital documents you created and any photos you took of your written work to your teacher.

Make sure you keep any hand written work you did in your exercise book or folder as your teacher may need to see these when you are back in class.

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