Sound waves
The topic of sound and waves lends itself well to a wide variety of practical activities which allow students to develop their own understanding. This list provides a range of suggested activities and teaching strategies, as well as resources which support non-specialists in using equipment. From 2014, students should learn about:
• frequencies of sound waves, measured in hertz (Hz); echoes, reflection and absorption of sound
• sound needs a medium to travel in
• the speed of sound in air, in water, in solids
• sound produced by vibrations of objects, in loudspeakers, detected by their effects on microphone diaphragm and the ear drum
• sound waves are longitudinal
• the auditory range of humans and animals
Visit the secondary science webpage to access all lists: www.nationalstemcentre.org.uk/secondaryscience
Wave Machine
Sound waves are longitudinal and this film shows how to make and demonstrate a transverse wave machine - but it’s just too good not to include here!
The word “machine” probably gives the wrong impression - this machine is built simply and cheaply from duct tape, kebab sticks and jelly babies. It’s a fantastic introduction to the whole topic of waves showing that, although the wave moves all the way along the machine, the particles (jelly babies in this case) just vibrate. The film provides full details about how to make the machine, but many teachers, having used it once, may want to encourage students to help them make it during the lesson.
Use it alongside the more usual slinky spring which demonstrates both transverse and longitudinal waves.
Signal Generator
A very helpful film for teachers who want to demonstrate the properties of sound waves but are not yet that confident when using a signal generator. This film will help teachers to feel much more relaxed about using this equipment and, having had a practice, using it with a class should be much more straightforward.
You’ll see how to demonstrate that changing the frequency changes the pitch of the sound and how changing the amplitude changes the volume.
For the more adventurous, connecting an oscilloscope can show the same relationships visually.
Oscilloscope
This film is included here because teachers who are keen to use a signal generator in their lessons to demonstrate sound waves (see the resource above) may also appreciate some support in setting up and using an oscilloscope.
Range of Human Hearing
This is a simpe activity to using a signal generator, amplifier and loudspeaker to investigate the range of human hearing (young people).
Noisy Coat Hangers *suitable for home teaching*
Start collecting wire coat hangers now! This is an experiment that has to be heard to be believed. Students and teachers alike will be amazed just how much louder sounds are when they travel to your ears via a solid rather than (gaseous) air.
Go on to ask students to use particle theory to explain the difference.
Unusually, the instructions for this experiment are available in multiple languages. It would be great to use during a languages week, or maybe you’d like to bring science to a Spanish or French lesson?
Sound 11-14
There’s a lot of high quality information here along with plenty of detail about a good variety of activities from the Institute of Physics. It takes a little bit of time to understand how the resource is structured but it’s well worth the effort.
Old hands may want to turn straight to the Teaching Approaches, whilst those outside their specialist area are likely to appreciate the background information provided by the Physics Narratives and the key points to bring out when working with students given in the Teaching and Learning Issues.
Particularly recommended activities from the Teaching Approaches are
· 'Introducing sources' and 'Sounds meeting detectors'
· 'Pitch and frequency' and 'Range and frequency'
Sound
There is a wealth of activities on the theme of sound on offer in this teacher booklet which will amply repay time spent looking through it. Although the booklet itself is dated, the contents aren’t and teachers are almost bound to find something they haven’t seen before.
Many will know of the “bell in a jar” demonstration where a ringing bell becomes inaudible as a vacuum pump removes the air from the jar. This booklet offers a version that all students can try for themselves: a small jingle bell in a syringe which students can partly empty of air to form a partial vacuum.
Physics in Concert
This resource is highly recommended. It’s an updated and Key Stage Three version of the “Ashfield Music Festival” which some teachers might have used before. The idea is that students play the roles of sound engineer, lighting engineer and electrical engineer (the sound engineer role is what links it to this topic) when thinking about the physics behind putting on a music festival.
It’s designed to encourage students, particularly girls, to study physics further and experience shows that it does exactly what it says on the tin.
Everything you’ll need is provided here including a powerpoint presentation to talk through with students, teacher notes and accompanying students worksheets. It’s a great project for students to get their teeth into either over a sequence of lessons or in a special off-timetable day.
How Science Works: Bad Vibes
in this video, acoustic engineer Professor Trevor Cox describes a far-reaching internet experiment to discover the worst sound in the world. Teachers may wish to focus on one or two aspects of working scientifically when using this film with the resource listed below, such as:
• pay attention to objectivity and concern for accuracy, precision, repeatability and reproducibility
• understand that scientific methods and theories develop as earlier explanations are modified to take account of new evidence and ideas, together with the importance of publishing results and peer review
Using Bad Vibes in the Classroom
This film shows how the video "Bad Vibes" can be used in the classroom to look at working scientifically. It illustrates the collection and analysis of scientific data, quantitative and qualitative methods, and the role of the scientific community in validating changes in scientific ideas.
Professor Cox talks us through the peer review process, explaining how it shaped his development of a website designed to carry out research on the world's worst sounds.
Physics and birdsong
An interesting and alternative approach to the teaching of graphs and sound. This site provides a free download teaching pack (with full teachers notes and an annotated slideshow) that aims to support students graph drawing skills whilst also teaching them about sound, pitch, frequency, loudness and amplitude. Students listen to birds sounds and then have to sketch frequency/time or loudness/time graphs to help them get a ‘feel’ for how a variable that changes over time can be represented.