Third Age Physics

This post serves as the 'contents page' for a series of videos to be uploaded to YouTube during the final months of 2020. In essence, they are the online version of various physics-inspired sessions put together during recent years for the 1000+ members of my local U3A branch. This year, being the fun-fest that it isn't, requires a different approach - one that doesn't depend upon face-to-face indoor events. Assiduous readers of my blog - if there are any - will realise that this is the third series of videos to be made available this year, and the second to be dedicated to the non-expert but highly intelligent U3A participants I have come to love spending time with. (Details of the first 'U3A series' may be found in an earlier post, here. There is also a series curated from the surviving recordings of my pre-retirement lectures for Foundation Year Physics students; the details are here.) Apart from providing the YouTube address of each video, I'll use the post as a convenient repository for the details of any 'further reading' (or viewing) suggestions that come to mind. What I'll not be able to offer here is access to the online discussion/Q&A sessions planned as a follow-up to the initial video; sorry, but those must remain within the purview of my local U3A coordinators.

Each video will have been recorded in a single take, and without a script or notes in order to try to reproduce the 'live' experience. Also, it would simply be too dispiriting to deliver a long and stilted monologue by reading from a script ... oh how I miss sharing my love of science face-to-face with a group of people who can provide real-time feedback!  This video-based approach is, you can tell, not my ideal - although a variant of it worked very well when I was teaching students (see here) as face-to-face follow-up sessions were built into the process.  The upshot is that viewers will get all my stumbles, throat-clearing, failures in memory and moments of lost track: forbearance is a good quality in such contexts. I am not, as you will rapidly discern, a 'natural' in front of the camera. (I'm reminded of the media training day I attended a few years prior to retiring during which I was recorded being interviewed: the feedback was hilarious. Apparently, one of my sentences lasted 35 seconds! You have been warned.)

Only after beginning the project did it fully dawn on me what a significant undertaking it was. It's far more tiring to record a talk than it is to share it face-to-face with people. Furthermore, I have allowed myself the opportunity to include more material than I might have risked in a live performance. I have tried not to lose all sense of restraint in this regard but it's been good to have the opportunity of sharing a few more artefacts for instance. What I will try to ensure is that I build a 'sanity break' into the videos every 40 minutes or so: a juncture at which it's easily possible to have a rest. I may do this within a given video or by splitting the thing into two or more parts.

One more thing: although it's entirely possible to read my blog and watch the videos on any suitable device, the larger the screen the more you'll see. It was ever digitally thus 😉

1. What's so special about the Earth?
87 minutes, with an intermission at 42 minutes; there is seven minutes-worth of optional additional material tacked onto the end.

The original U3A programme abstract read: "With the discovery of planets orbiting stars other than our own Sun, several of which have been labelled ‘Earth-like’, it might be tempting to conclude that we’re really not that special. Moreover, some might argue that humankind ought to consider spreading out and colonising such exoplanets. Is any of this reasonable?" This topic is tackled first as there is only one practical demonstration I wished to show. This was, in a way, selected as the test-bed for subsequent videos in the present series.

There are a couple of my former blog posts which include relevant information and additional links: on star and planetary formation and on the very subject of the U3A talk at the heart of this topic, here. Indeed, many of the links shown below are also included in these earlier posts.

Useful video/animation links cited within the talk include:
On the scale of bodies in the Solar System
On solar wind 
On tectonic plate movement and similarly here
On the Earth-Moon rotation about their barycentre  
A fun look at the earth’s rotation on its axis.
Also, there's a great TV documentary available on the importance of the Moon. Whilst on the subject, this is a link to a brief computer simulated animation depicting the probable violent birth of our moon after the Earth collided with a Mars-sized planet in the early years of the Solar System; it shows clearly why the chemical/mineral composition of the Moon is almost identical to the Earth: they both solidified from the same 'mixing pot'. Indeed, since making the video I have come across another contribution to life on Earth made by the Moon: apparently, it once had a weak magnetic field which provided important additional shielding for emerging life on our planet - see here for details.
(Diagrams and figures used in the slides have references to their sources included on the page itself.) 

p.s. I am indebted to Leigh Edwards for pointing out in a comment on YouTube that there are ~100-200 billion stars in the Milky Way - I used the word "million" in error; my apologies.


2. Radiation: bad, benign, beneficial - Parts 1 ,2 & 3

Part 1: discovering the language (51 minutes)

Part 2: bad and 'benign' - balancing risk (62 minutes, with an intermission at 27 minutes)

Part 3: beneficial uses of radiation (32 minutes)

The original U3A programme abstract read: "Radiation, has been of considerable interest for over a century – but how much do we know about it? Together, we’ll take a look at its origins and effects – bad, benign and beneficial – from a scientific perspective."

There is a blog post written previously which include relevant information and additional links, here. 

UK figures on radiation exposure. Other links are shown within the slides in the video.

3. Glass: a look inside - science, technology and art
Part 1: what is a glass and what goes into the mix? Glass in nature, both hot and cold. (58 minutes, with a break at 32 minutes)

Part 2: glass-making technology; looking deeper inside. (45 minutes)

Part 3: staining and painting, sculpture and culture. (41 minutes)

Part 4: technology and engineering - glass in the development of science, communications, consumer items, architecture and the kitchen. (55 minutes, with a break at 33 minutes)

Part 5: towards the cutting edge - bioactive glassy materials and some major breakthroughs in physics; myths, breakages and sound. (67 minutes, with a break at 37 minutes)

The original U3A programme abstract read: ‘Glass has existed in nature for billions of years; mankind has been using it since the Stone Age. It is ubiquitous, often irreplaceable, in art, in technology & engineering, & in science. We'll discover, at the level of its constituent atoms, what a glass is; we'll look at its uses in technology, in art, architecture, & in science: from bottles to stained glass windows, to scaffolds for re-generating bones & for drug delivery.’ This online version covers material from what was originally a little less than four hours of 'live' event spread across three sessions, hence the necessity for multiple videos. Having indulged myself by including an extended range of 'show-and-tell' artefacts, the five constituent videos in this series will, if you watch them all, take approximately four and a half hours. By the way, I hope you like the green-screen backdrops to this series: if nothing else, it will make a change from the bookcases against my study wall.

There are several of my former blog posts which include relevant information and additional links, but here I include only three of them: here, here and here. There is also a one-hour video, recorded some years ago in Canterbury’s Heritage Museum – now closed, sadly – which covers some of the same ground within a single one-hour video: here. 

Additionally, you might like to augment this series with the following material:

On 'Prince Rupert's drops' - thermally toughened glass; there are some great ultra-slow motion sequences. YouTube provides a treasure-trove of accessible material on glass-blowing, float glass processing, making stained glass panels and all sorts of other relevant topics.

Some of the general interest books on glass from my shelves, should you want or need additional reading material:

4. Colour 

Part 1: introduction, Newton's approach (the electromagnetic spectrum, prisms, rainbows etc.) - 35 minutes.
Part 2: a look at Goethe's observations and Turner's use of his idea (perception and interpretation) - 34 minutes.

There are a lot of demonstration-type experiments in the face-to-face original session, so it's impracticable even to attempt to translate this into video format given my limited home setup. However, by stripping out the more challenging demonstrations, a variant of the material becomes a (hopefully serviceable) possibility.

The original U3A programme abstract read: ‘Most of us grew up on Isaac Newton’s theory of colour; we use it to explain a multitude of everyday things like rainbows. There were alternative theories however, like those derived from the careful observations of Johann Wolfgang von Goethe – who influenced JMW Turner’s choice of colours very significantly. We’ll explore the world of colour from a scientific perspective, and in the process consider the role of individual perception in our technicolour world.’
There are a couple of my earlier blog posts which include relevant information and additional links: here and here including a link to one of the projects I undertook with the Turner Contemporary gallery in Margate (here). 

Also, there's a fascinating video series available on Goethe’s approach to colour.

If you want to dig a little deeper into the phenomenon of the refraction of light, then video 30 in the 'Physics Beyond the House' series will provide further details; other videos in the series offer additional information on the electromagnetic spectrum etc.