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Holiday Physics: Resonance

Chris Creagh's picture

There is a lecture demo in the resources section called "Resonance in a Rotating Tube" but...

Interesting observation: If I take a cardboard tube from the seasonal wrapping paper and wave it about I do not get resonance in the same way. Why is it so? Why does it work for the pool pipe and not the cardboard tube?

I can hear the resonant frequency of the tube if I put my ear to one open end and point the other end at a source of white noise (the airconditioner). I know it is resonating because if I put my hand over the end of the tube nearest the airconditioner, the fundamental frequency of the sound I hear drops considerably even though it is still somewhat "white noise" like. By recalling the formula it must in fact be half the original frequency because there is now a quarter wavelength in the tube as opposed to half a wavelength.

I checked my assumptions about using the noise from the airconditioner as a source of "white noise" by putting the open end of a mug against my ear and as I bring the mug closer to my ear I hear the white noise of the airconditioner but it seems lower than the ambient sound so the mug must be eliminating some frequencies in the "white noise" and not others. My mother use to call this effect the "sound of the sea" when she would put a shell against my ear.

Anyway why does the pool pipe resonate but the cardboard one does not? My partner says it must be the "Q" factor (or quality factor). An object with a high Q resonates in a narrow band of frequency with high amplitude. This is dangerous if it is a bridge and why bridges have dampers on them. So my cardboard tube must have a low Q i.e. each time the sound wave traverses the tube it loses so much energy that audable resonance can not be sustained i.e. the cardboard walls are too soft and squishy. So now I am looking for a cardboard tube with solid walls to test this new theory.

Found one! And yes there is possibly resonance there when I wave it around but not as much as with the plastic pool pipe.

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Early Career Teachers (ECTs)

Chris Creagh's picture

Universities are interesting places, you tend to get an academic position on the strength of your research and then you learn how to teach "on the job". This can be quite a stressful thing and no matter what your initial teaching load, you feel that you have been “thrown in at the deep end”. There are just so many things that you do not know! So many details to pay attention to!

Hopefully you are teaching in an area where you are familiar with the content so that bit is ok. You think you have all the teaching materials ready, and the rooms booked, and the recording of the lectures arranged, and the websites set up with new tests and assignments, and the textbooks ordered for the bookshop, and the exam office notified that you will need an exam, and you have checked the timetable for clashes and resolved what you can, and the students have been allocated to groups and labs, and you have informed the lab techs of the labs you will be doing and the days that they will run… and then the first day comes and you are standing in-front of a class hoping like hell that it all comes together, because really, what do you know about teaching other than what you have experienced yourself?

Somewhere in the next three years you will do a tertiary teaching course, you will find people who will unofficially mentor you and you will get the admin under control so that there is time to think, reflect on your teaching practice and ask how you can do it better. This is the moment you embark on the search for answers to the puzzle of a lifetime!

So, those of you that have survived this "ordeal by fire" any tips and hints for the ECTs?

Who are we/am I?

Chris Creagh's picture

At the moment there are three of us, me, Dr. Christine Creagh (the person with the Fellowship), Associate Prof. Rob Phillips (critical friend and consultant on matters of education and the internet) and Allan Boyd (web dude extraordinaire). We have a few other regular contributors lined up for when we get into full swing and as they join us I will ask them to introduce themselves and I am sure Rob and Allan will put up a post about themselves soon. So to me...

I started my undergraduate physics degree in 1991 when I was around 36years old. Prior to that I had enjoyed physics in high school and then became a Diagnostic Radiographer after 3 short years studying at Curtin University (then WAIT). It was a good job, good pay but on-call for emergencies was a bit stressful. Anyway I worked with the Med Dep long enough to get pro-rata long service leave when I left. My next serious job was as a high-school lab assistant which I found to be a very constructive and creative experience. Basically I had access to all the toys! After that there was about 10years as a stay-at-home mum in various cities around the world.

Back to 1991. I wanted to become a librarian but you need a degree in something else to do that. So I chose a passion from long ago as the starting degree, Physics, and somehow never managed to get back to the library. I blame my undergraduate degree choice on Mr. Nuffield and his physics course which was running in my high school in the late 1960s. It was inspiring! Anyway as you have already surmised I got through undergrad, honours and eventually did a PhD in physics. Right back at the start of my undergrad studies though I thought it might be interesting to do the concurrent Grad. Dip. Ed. that Murdoch Uni was offering and this is where I picked up my passion for teaching and engaging in it as a reflective practitioner.

I have been lucky/unlucky enough to teach first year physics to a mixed discipline group of students since the start of my academic career. Lucky in that it has always posed challenges which have kept me searching for ways to engage students in their studies. Unlucky for the same reasons in that this continuous quest takes time, and time is a limited resource, so something else in an academic’s life suffers as a consequence. However I am now playing the end game, looking towards retirement and I would like to tidy up all the loose ends of the things I have been doing, give away what I can, encourage where I can, and of course the ultimate goal, leave the place a slightly better place than I found it.

So I hope you find what we will create here useful. I hope it brings people who teach physics together so that they can support each other. For we are a widely scattered community across the institutions of the world where the academic sitting next to you may not understand the language of physics education.



I'm Allan Boyd. I'm the Physcom website developer.

I've been building the internet since 1998. I run my own web design/development business: radicalhack.com. I've built so many sites I have lost count - you can see some examples of my work here: http://radicalhack.com.

I mostly build with Drupal -  a popular open source Content Management System powering thousands of sites across the web. https://www.drupal.org/

I began designing and developing this website for Chris late in 2014. What started as a simple upgrade and rebuild of the initial WIO website (http://workitoutts.com) has slowly evolved into a robust Resource and Community Forum project. There has been a lot of testing and tweaking throughout 2015 to bring the site inline with the scope.

Rob Phillips has been invaluable throughout the development process. He has a good knowledge about how Drupal works and without his guidance (and patience) we could not have come so far!

Over several months we discussed how the site would be used, and ways in which content could be displayed. Using Drupal I installed several versions of the Forum and Taxonomy software to get the right configuration. The two parts of the site - Resources and Community need to "talk" to each other. We use a taxonomy/term reference system to help display various bits of content across the site.

So far so good.

Web development is an organic process, and often it is not clear what a website wants to do until people start using it! But I reckon we are nearly there.

All we need now is for folks to add more content. To engage and comment. The more topics and comments there are, the better I can create displays which match the content. To get involved, sign up by clicking the button below!


Thanks and enjoy!


Allan Boyd

Rob Phillips's picture

I'm Rob Phillips. I'm a semi-retired academic, doing projects and some online teaching because it's interesting and enjoyable. I've worked in educational technology since 1992, after an earlier career as a theoretical chemistry researcher, and subsequently as a mainframe systems programmer.

My substantive role was as an Educational Designer, working with academics to design technology-enhanced learning environments that students can learn from. I've worked across most disciplines over the years, and I'm currently developing a training module for paediatricians and allied health professionals about Fetal Alcohol Spectrum Disorder. After many years, I'm also doing the technical development on this project, which has been a frustrating, but sometimes fun experience.

I'm not a practicing Physicist, but I possibly remember more Physics than I do Chemistry, despite that being my undergraduate major. My comments on the forum are more likely about how to teach difficult concepts, rather than the concepts themselves...

I am working as an online tutor for the School of Education at Curtin University for units offered through Open Universities Australia. I teach first years from diverse backgounds about 'living and learnng about the digital world' and about scientific inquiry skills. In this latter unit, students inquire into a sustainability or environmental issue of their own choice, and I facilitate their journey through this investigation.

An explanation of PhysCom.Net

Chris Creagh's picture

This website has two parts. On one side of the coin are a set of resources, the initial ones being the result of an Australian National OLT Fellowship. I would like to see this set of resources grow through the contribution of other physics educators. The other side of the coin is a community forum where we can discuss all things pertaining to learning and teaching in physics. The two sides are linked by some gooey stuff in the middle called tags and categories that try and bring together material of a common disposition. As people contribute more material, either resources or discussion, the website will grow. If we find a lot of “stuff” happening in a particular area then it will get its own little category. So the website will change and develop organically as people use it! So cool!

While the initial site is funded from the OLT Fellowship the Australian Institute of Physics has pledged on-going support so we have a modicum of sustainability.  J

Till next time…

Chris Creagh

Welcome to the site!


I teach physics to first and second year university students. In order to do this effectively I have had to gain a deep understanding of my topic. And, I had to learn how to construct a learning environment for my students that would allow them to gain their own understanding of the content and culture of physics.

Learning new stuff is hard and it takes time. Trying to do it on your own with little or no support makes it so hard that you could end up subjugating your personal time, sleep and health to make it work. While I, and I assume the wider scientific community, welcomes more students studying physics and mathematics, it should not be at the expense of the health and wellbeing of their teachers.

This website therefore has been constructed to help us, help us. It is a place where we can share ideas, discoveries, learning strategies, resources and hopefully in a short time it will become a ‘useful place’ for new and not so new physics educators.

Please take what you find here, modify it and make it fit-for-use for you, your students and your learning and teaching environment. Then feedback, what worked and what did not, so others do not have to reinvent the wheel.

Keep on keeping on,

Chris Creagh