Thomas shows Robin reminisce about (nearly) an academic year of podcasting. They describe their favourite practicals and are joined by Patrick Kaplo. Robin and Thomas between them share five practicals that they really enjoy as well as describing their best and worst moments of the year.
Finding the mass of a 1m ruler using a 1N weight @ 07:17
SHC using a kettle @ 11:41
Exploring uncertainty and efficacy of measuring devices using measuring 4 ohm resistors @ 20:16
Bond energy using a kettle @ 22:55
High Points and ideas for season 2 @ 25:46
Thomas’ PIM – Bias @ 32:09
Patrick Kaplo @ 39:48
Summary
Physics, physics, physics, Thomas and Robin just love to talk about how they teach it. Perhaps too much. They chat about the year they have had making the podcast and share some of their favourite practicals along the way.
Finding the mass of a 1m ruler using a 1N weight
Thomas wasn’t super clear in the podcast about this, but has made a Google Slide deck about it. Basically: Find a series of balance points for the ruler pivoted on the edge of a bench with the weight sitting on the but of ruler sticking out. clockwise moments = anticlockwise moments. The image below is from the google slide deck.
Join in!
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
Thomas shows Robin his package… A montage of chats he’s had with teachers who have worked abroad. The Rev (Episode 21), regular co-host Patrick Kaplo and one of Thomas’ old student teachers all give their thoughts on this adventure.
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
Thomas and Robin are joined by IoP Misconceptions expert, Alex Mathie.
Timestamps
Introductions @ 00:15
Physics in the News @ 01:25
Misconceptions @ 02:47
Mistake vs Misconception @ 03:00
Why are misconceptions important in physics? @ 04:07
Examples of misconceptions @ 06:27
Models and misconceptions @ 08:55
Addressing misconceptions @ 10:33
IoP Spark and misconceptions @ 15:50
PIPER @ 24:37
What could a teacher do tomorrow to address misconceptions? @ 26:17
Physics and Philosophy @ 30:10
Summary
What is it that makes physics a unique teaching challenge? Well dealing with misconceptions must be one of the prime candidates. More than perhaps any other subject, physics students end up with some stubbornly embedded ideas that might be along the right lines but are definitely on the wrong track.
Thomas found the YouTube video Why is Light slower in glass? – Sixty Symbols useful in fixing one of his misconceptions. The other (using the gradient of a tangent to a V vs I graph) is incorrect, you use the point on the graph of course.
As a teacher, think about your questioning and how it might root out common misconceptions. Check out the IOP Spark misconceptions section to see what might crop up in the topic you’re teaching.
Join in!
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
Thomas and Robin are joined by Patrick Kaplo and NQT, Imogen House to talk about our first years in teaching, which leads to a wide ranging chat about highs and lows, being liked vs respected and teaching pedagogy.
Timestamps
Introductions @ 00:23
NQT Mistakes @ 01:32
NQT Best Bits @ 12:28
Respect vs Being Liked @ 15:12
Pedagogy in teacher training @ 19:09
Survey Feedback @ 23:48
Summary
What’s the collective noun for a group of physics teachers? Answers on a postcard please (or on Twitter, @physicstp).
Episode 31 finds Thomas, Patrick and Robin re-joined by Imogen who was a guest of an early podcast as a physics NQT. Imogen is now through her NQT year and joined us for an ‘all-request’ episode 31. We were contacted by @thePhysicsNQT on Twitter who asked us to explore some of the things that went wrong when we were early-career teachers.
Thomas recalls inviting bedlam by promising real-world relevance in one of his early lessons, thus inviting constant questions such as “what’s the relevance of xxx”; “How is this relevant to the world?” etc.
The gang got to reminiscing and unsurprisingly pupil behaviour became a theme, but Patrick did point to his years of experience giving him increased confidence in his practice, so that he is now much more ready to acknowledge and address mistakes. It’s an important point: professional insecurity doesn’t encourage reflection. It’s confidence in your practice that makes you better equipped to take feedback.
More positively, relationships were celebrated as a way to build positive environments based on mutual respect. All the teachers agreed that it is easy to confuse a positive mutually respectful relationship with ‘being liked’, particularly at the start of the year. Respect first and ‘liking’ second was the maxim with Imogen reflecting that she is likely to be stricter up front in future.
Moving back to physics, Robin postulated that subject-specific training knocks spots off ‘generic pedagogy’ with Patrick observing that physics has definite and unique demands that need specific training.
Congratulations and thanks to Helen Le-Mar: the winner of a T Shirt for completing our survey. The crew finished by looking at the results of the survey and looked forward to the variety that we are planning based on the results. Thanks to everyone who’s supported the podcast by volunteering, promoting, participating and suggesting. Keep spreading the word and letting us know what you want to hear!
Join in!
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
How would you teach forces to 11 year olds? @ 05:00
Guidance for a non-specialist @ 21:10
Summary
Robin and Thomas were back to basics this week. With Patrick busy bringing physics joy to a
new generation of New Hampshirites (that’s really what residents of New
Hampshire are called – I Googled it and everything), it was just the two
physics geeks getting together to talk forces.
Before we got to the main business we had time to welcome IOP’s new Spark website which gathers together and updates the resources offered to teachers by the IOP. With a new section on misconceptions and a much slicker look and feel, IOP Spark should be in every physics teacher’s bookmarks – have a look at spark.iop.org.
If you completed our listener survey, a big thank you! The results show that you love the Podcast,
and particularly those episodes where you get tips and pointers for teaching
specific topics, and so this week we zeroed in on KS3 Forces, with TWP asking
the question, “What would your first three lessons be for introducing forces in
year 7 or 8?”
We discussed starting with the idea of a “push, pull or twist”
and asking students to think about ways this might work. TWP uses a circus of different types of forces
to get students thinking about pushes, pulls and twists and discussing the
origins of different types of forces.
A common misconception is that movement requires a force (e.g.
a tennis ball travelling over the net ‘must’ have a force that makes it move
forward). This is not true, and Robin said
that he would like students to have been introduced to the idea that persistent
motion is the natural state and that our experience of friction and drag make
us think that objects slow down and stop.
Another concept to introduce is force arrows – an arrow in
the direction of the push, pull or twist, and whose length is proportional to
the size of the force. Robin suggested
re-visiting the earlier circus and asking students to add force arrows to their
earlier observations.
It is one area when lots of practical investigation can aid
understanding, particularly on the idea of resistive forces such as friction
and drag.
Don’t forget to tell us how it goes and share your tips. Details on how to get in touch are below. Thanks for listening.
Chit
Thomas’ Carousel on Forces might include the following:
a boat (origami will do) floating in a tub of water
ping pong ball with two straws and a zig zag obstacle course made with text books
popping toy
something static like a heavy weight on a piece of paper
wind up toy
flannel to wring out
pendulum
pull along toy
weight hanging on a spring
anything you can think of that pushes, pulls or twists!
Join in!
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
This is a way to determine the Young Modulus as an individual, rather than group practical. For years I thought that you needed a pulley for the wire, but it turns out you don’t. Without that limiting factor, it becomes a pfaff reducing exercise.
Summary
Get a plank of “whatever you can find” width, about 1.2m long, drive a screw in about 5cm from one end. Photocopy a normal ruler at 100% then at 90%. Check the reduction is accurate! Use the 90% to make a vernier scale. Get about 2m of 32swg copper wire and tape the vernier scale to the wire at 1m from the nail. Line the vernier up with the 100% scale and gently hang 1N weights to the end of the wire that hangs off the end of the plank, measuring each extension. The diameter of the wire is done traditionally by using a micrometer or looking up the diameter of swg wire in mm.
Steps and Photos
This is one of our dynamics ramps, but any old plank could be used. It needs to be more than 1m long and should stick out over the desk to give the weights room to hang. This is 32swg copper wire, diameter 0.27mm90% photocopy of the ruler. Do check that 10.0cm in the copy is 9.0cm on the real ruler (some photocopiers reduce by a few percent as a matter of course). It may take some trial and error (keep notes for next time…). In the experiment I took photos of, I used a real ruler for the 100%, but realise a photocopy would be better.The vernier scale at 1m from the screw. It is sellotaped on. ± 2mm is fine (± 0.2% uncertainty is negligible compared to the extension and area)Wear goggles, but you also need some protection from flying wires (not such an issue with copper, but other alloys can store a lot of energy). These cardboard pieces help prevent the wire from flying around. e.g. with 32swg copper you 1-10N is fine and prety safe if it breaks, but with nichrome you might want 1-40N in 4N steps which is altogether more interesting if it snaps.)I use a 10g hanger to tension the wire so that there is a nice talking point about the ice hockey stick shape of the graph (a false extension on the first weight because it is taking up the slack and pulling out kinks). Note the hanger is near the floor and there is a sandbag in case the weights fall: it stops you putting your foot there more than protecting the floor.
For those of you who assess against CPAC, this is a good experiment for 3a (Identifying Risks) and 3b (Working Safely). I use the Hazard | Risk | Control approach to a risk assessment. e.g.
Hazard
Risk
Control
Wire breaking.
Flailing wire causing damage to exposed skin/eyes. Weight falling on feet.
Eye protection. Weights over wire for kinetic energy transfer. Sandbag on floor.
I realise that the weights on foot issue is not a massive one, and using copper wire makes the flailing wire unlikely too, but they do need practise thinking about these things for bigger challenges ahead.
The main pfaff is getting the top ruler (the scale) parallel with the wire. The bottom ruler is just raising the vernier to the height of the top scale. I now realise I could dispense with both rulers and use a 100% photocopy (or thinner ruler!) for the scale. This reading would be 828.8mm.Normal micrometer screw gauge practice for the diameter (three times). Check the micrometer for zero error. I would do a whole lesson on micrometers well before attempting Young modulus, and would give a few a nice zero error using the little adjustment spanner that comes with them. Area is πd²/4 (rather than finding r, which just introduces another opportunity for mistakes). Uncertainty here (assuming a perfect zero) is ± 0.005mm (it is a reading) or 1.9% for the diameter so 3.7% for the area, which I would round up to 4% (I always err on the side of caution).My lab book, but before I stuck in a screw instead of using a G clamp! With 1m of 32swg copper you get about 1 mm extension per 4 N weight on the wire. The wire starts to slip at around 10-13N, and the general guidance is 5 < number of readings < 10 so the whole experiment can comfortably be done with one hanger with ten 1N weights on it. Assuming we discount the first couple of readings, making 2N our “zero” the uncertainty in the first real extension (2 to 3N) is ± 0.1mm on 0.3mm or 33%, but this reduces so by the fourth point (2 to 6N) the uncertainty is ± 0.1mm on 0.9mm or 11%.
With the pulley
Very similar to pulley but over the edge of the plank, honest!
Hooke’s Law using this apparatus – this was the wire hung over the end of the plank
Three graphs of real data showing how the pulley (middle) makes no difference, the first and third are with the wire simply hanging over the edge of the plank. The final one (green dots) is Hooke’s Law.
I also made a video.
I hope you found this useful. Any comments, suggestions etc. Please contact us through twitter on @physicstp or use the form below.
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
We discuss what’s gone well and badly this week with guest presenter Cara Wood and then chat about James de Winter’s thoughts on Maths in Physics teaching.
Timestamps
Introducing the Survey @ 01:45
What’s gone well and badly this week? @ 02:46
James de Winter interview @ 08:50
Post James chat @ 25:12
Summary
Cara Wood (she of the plucky string in episode 27) steps in for Patrick Kaplo to share her thoughts about what has gone well and badly this week. James de Winter then talks about Maths in Physics teaching: what can learned from the Maths department and the challenges Physics Teachers face. He mentions research by the ASE about cooperation between Maths and Physics departments and also Ed Southall’s book “Yes, but why?”. He also talks about how he has used numberless graphs and suggests a question you can ask yourself before each activity: What’s the point?
Cara reminded Thomas about the graph scale selector, but we couldn’t find a link to an example, can you?
Join in!
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
I think I am getting a bit blasé about publishing, two fails in two weeks. ?
When I create a Podcast Post I have to do three main jobs for the podcast to release properly:
Upload and attach the mp3
Tell the Post when to go live (5:00am on the next term-time Thursday – an arbitrary choice that I have stuck to)
Tell the Post it is a Podcast Episode (rather than a blog etc.)
Last week I failed at #2, this week I failed with #3. Both cases were because I changed the auto-tweet text. For some reason you have to completely start again from scratch if you want to change the release auto-tweet. This means copying and pasting all the content in to a new page, usually late at night, usually a bit frustrated…
I am making a checklist now. #1 is
“Check the damn tweet doesn’t have a spelling mistake!”
Enough procrastination. I have a pile of lab books to mark. ?
Patrick, Thomas and Robin get together to tackle ways to teach waves but not until they have touched on Jeff Bezos’ bid for extra-terrestrial adventure: Blue Origin.
Cara Wood was first up sharing tips for teaching waves. She introduces waves by simply getting
students to pluck a piece of string held in their teeth, so that they can see,
feel and hear vibrations, experience amplitude and frequency, and discuss waves
travelling through solids and gases. Patrick
loved this: really giving a tactile encounter with waves and their source. Robin made the tenuous link to cochlear
implants. Very similar is the metal coat hanger demo.
“You can’t beat a Slinky” according to Dan Toomey – thanks Dan! Patrick put us onto “Snakey springs” on amazon for a mighty £27, but we found them cheaper with a bit of persistence: £5.75 at Select School Supplies. Snakey Springs help to avoid Slinky tangles when demo-ing transverse waves. Thanks to Graham Thomson for the tip of setting a ball next to the slinky spring so that it gets struck as the wave passes and you can thus link frequency and energy. Graham pointed out the rich discussions you can have on time period, frequency, wave speed and wavelength all with the Slinky. Thomas was really impressed with Frank Noschese’s video using paper cups next to the Slinky to demonstrate constructive and destructive interference. Robin recalled a similar method to this to demonstrate the vibrational link to sound waves.
Thanks to Dr Joshua Griffiths and Graham Thompson who talked
about challenging students to produce features on ropes and Slinkies, such as
increasing numbers of standing waves and purposely frustrating by asking for
high frequency, long-wavelength waves.
This gives a good discussion of why it can’t be done!
Thanks to all the other folk too numerous to mention, who
also pointed us towards the Slinky as a ‘must-have’ for teaching waves.
Thanks to Dan Toomey for the salt / sand pendulum video. Thomas was delighted to report he had already done this and Patrick was keen to have a go.
John Hamilton’s use of acetate wave traces to demonstrate superposition makes a tough concept much easier for students to visualise – thanks John! Jed Marshall uses acetates to get across the tricky idea of wavefronts, alongside his ripple tank that students can struggle with and he kindly supplied a booklet to show how it worked. (photos below).
Thanks to John Hamilton
Thanks to John Hamilton
Thanks to Jed Marshall
How’s this for a handy mnemonic for longitudinal vs. transverse? Thanks to Chris Beason and K Physics 1.
Alom Shaha joined us for his PIM and he described his jelly baby wave machine. The video says it all: easy to make, and as Alom says, transformative in the teaching of waves! Reflection, refraction, amplitude and frequency – all easily demo-ed quickly and cheaply. Despite Jelly Babies being lost in translation, Patrick endorsed the machine and he still uses it, although the Gummy Bears may be past their sell-by date!
Signal generators, strings and vibration generators always go over well, particularly in conjunction with a stroboscope and Patrick described how he challenges students, not least through atmospheric use of Pink Floyd music! Don’t forget your Rubens tube too – it really helps discussing pressure differentials in sound waves. And if anyone has any tips to get the Kundt’s tube to work, let us know!
Paul from @PlanetReynolds on Twitter had a lovely dichromatic crystals demo which has “Wow factor” and his toppling dominos is a great way of demonstrating density’s effect on wave transmission. Just search on eBay for “optical glass cube” and “100 led finger lights“.
Thanks again to Dan Toomey for his tip on using superposition with loudspeakers, and don’t forget PhET, ripple tanks and “stadium waves”!
…and finally! Well done to Frank Noschese who we picked from the expensively engineered randomised name selection device. Frank will receive a personally signed copy of Alom Shaha’s Recipes for Wonder.
HAVE A GREAT HALF TERM!!
Join in!
Please share ideas or successes – or indeed questions by messaging us on BlueSky: https://bsky.app/profile/physicstp.bsky.social . You can also message us via our website contact form on every page of the web site at the.physicsteachingpodcast.com, or email using the address given in the podcast (if we remember). We are moving away from X but can be found there as @physicstp.
