We’ve touched on this before, but the assessment of practical work is a hot topic. As it happens, tonight’s Twitter #asechat is about just that subject:
Search ‘#asechat’ on twitter.
Starts 8pm UTC (by which time we should know if Rosetta has woken up); Helen Rogerson is your host tonight.
Comments regular Michael de Podesta has an excellent post about experimental technique:
Do it quick. Then, do it right.
Be sure to read to the end of the link for a particularly lovely aphorism.
It’s Friday night, so of course we’re sitting at home doing… geometrical constructions. Of course we are.
(via Matt Parker and Katie Steckles. Reminds me of gearsket.ch, which is also very good indeed on an iPad.)
Ofqual […] has decided that practicals will not be included in the reformed science exams because teachers mark them too generously. The science establishment is despairing.
— Guardian editorial, yesterday. Tip of the hat to the Wellcome Trust’s Clare Matterson, via Twitter.
No other film in this series provoked more discussion and argument than this. Mostly from me. It’s a classic demo and was highly-requested in the nomination stage of Get Set Demonstrate, yet I argued against filming it.
For many years I made essentially all the science programmes that went out during the UK’s teatime ‘children’s television’ window, and there were only a few demonstrations I flat-out refused to show. This was one of them. You can show a safe method, you can treat the science with due respect… but with video you have precious little knowledge of your audience. You can’t tell when their attention has drifted away and they’ve maybe missed a crucial detail, you can’t be 100% certain of the message they take home, and most importantly you can’t guess what they might be tempted to try for themselves.
In person, the heat from the fireball is impressive: on video, it’s the size of your TV, or a YouTube window, or your phone. And it’s cold.
Film-makers can’t be responsible for the behaviour of their audience (discuss, 20 marks), but in this case the risk is very, very high. If 100,000 children saw the demo in our show, and 1 in 1,000 tried it themselves, and 1 in 100 set the curtains alight… that’s not something I ever wanted on my conscience. It’s not that the demo is too dangerous, it’s that it’s too easy. It’s trivial to perform it yourself in a kitchen, and the results can (and will) be catastrophic. So I never filmed the demo. Until now.
Others on the team eventually convinced me, using effectively the same argument applied backwards. The demo is straightforward to reproduce, and reproducing it is dangerous. Knowing that – understanding how and why oil fires are dangerous – might just save someone’s life, and for that reason alone, the team argued, this demo should be known and used in schools, and hence we should make this film.
I’m glad we did.
Three quick notes:
This film was produced for the Get Set Demonstrate project. Click through for teaching notes, and take the pledge to perform a demonstration to your students on Demo Day, 20th March 2014.
See those blue bars in the photo above? That’s you, that is.
Huge thanks to everyone who’s tweeted, said something positive on Facebook, posted to Boing Boing, whatever – yesterday was this site’s busiest day to date by a factor of five. Then today’s hit twice yesterday’s page views. Amazing, not to mention gratifying, but traffic is nothing compared to all your positive comments.
This site is itself an experiment, trying to plug a gap we’ve been worrying about for years. It looks like we’ve struck a chord. Fantastic, and thank you.
If you’re a teacher in the UK: join Demo Day 2014. Take the pledge to perform a demonstration for your students, on 20th March. It doesn’t have to be one of the demos featured here, the choice is up to you. But take the pledge, and spread the word:
Get Set… Demonstrate, at the British Science Association.
We’ve another of our demo films each day this week (and on Monday – bonus!), and we’ll keep the site ticking over until the grand premier of our epic Demo documentary film. Early March for that, maybe?
Meanwhile, it looks like Alom and I are making three more films of biology practicals in the near future. Who’s next? Is it time for some maths, or computer science? Or would the physicists get jealous?
Spotted on Twitter:
My colleague Charlotte set this up before xmas…tis only just ready #chemistryrainbow #RealTimeChem @ChemistryatYork pic.twitter.com/KVsRm9VbO4
— Emma Dux (@Duxie_Em) January 6, 2014
Fantastic. Emma later noted that it’s absolutely as simple as it looks: a condenser tube filled with universal indicator solution, with acid added at one end and base at the other. Then you “wait ages” – ie. a couple of weeks.
Mighty pretty.
I love this demo, but it’s one of those oddly bimodal ones – you can interact with it in two different ways:
The challenge for the demonstrator is to balance their audience’s natural inclination to roll the marbles themselves with their inclination to retain control and direct attention. That is: play vs. lecture, or perhaps more appropriately here, interactive exhibit vs. demonstration.
We explore this a little in the forthcoming Demo film, which starts with a candle flame. We all love staring at the flames of an open fire, but we don’t necessarily learn very much about combustion by doing so. How we use a demonstration is perhaps more important than the demonstration itself. That’s certainly the case for teaching, and I suspect also true for storytelling.
Video found via The Kid Should See This, which also links to this useful video showing assembly.
A scary article in the NY Times last Friday about a chemistry demo they refer to as “the rainbow”:
“With about 30 students watching from their desks, a snakelike flame tore through the air, missing the students closest to the teacher’s desk, but enveloping Alonzo Yanes, 16, searing and melting the skin on his face and body, according to witnesses. He was in critical condition on Friday[…]”
Just weeks ago, the article relates, the demo was the focus of a safety bulletin from the US Chemical Safety Board, and this film:
Here in the UK, I think we’d more commonly refer to the demo as “Flame colours”, and at the head of this post is a photo I took of it a few years ago. As best I can tell, the cause of the accidents in the US has been demonstrators topping up the flame straight from the methanol bottle, leading to the ignition of a large volume of fuel vapour.
Now, I’d hope most people reading this blog will be wincing right now. It was drilled into us (in school) that you never open a bottle of fuel near a naked flame, and that the correct procedure here is to ensure the watch glasses are cold before adding a small amount of fuel (typically with a pipette), then sealing the fuel bottle and removing it to a safe distance, before lighting the mixture in the watch glasses.
That would be standard lab practice, and it’s near-inconceivable that a teacher would pour meths from a bottle directly onto a flame. However, one thing we learned from SciCast is that we’re into the second generation of science teachers who’ve never really ‘done’ practical science. Recent science graduates don’t necessarily know how to handle flammable materials; they may never have been taught.
That generational knowledge gap was one impetus behind the demonstration films Alom and I have been making for the National STEM Centre and others, and also for this website. So pass this on, please, and let’s not make assumptions.
Oh, and if you’re a teacher in the UK, the version of this demo you should do is probably the one with ethanol spray bottles. That’s the version the Royal Society of Chemistry and Nuffield promote, but – as ever – check with CLEAPSS for their standing advice.
[EDIT 9/1/2014 – The RSC’s Education in Chemistry blog has picked up the story. Their post includes a quote from Steve Jones, Director of CLEAPSS.]
[EDIT 2 15/1/2014 – I somehow missed the NY Times’ follow-up story about the school involved in the incident above being inspected by the Fire Department, and being given notices to improve on a range of issues. Also, for the UK audience I should note that the Scottish equivalent of CLEAPSS is SSERC.]
Former FameLabber Feargus McAuliffe speaks at TEDxDublin about how he to learned to share science by telling stories about it.
It’s an interesting watch, but I’d go much further than Feargus: I think the peculiarity is the formalised ‘present your evidence’ model of science, and that in the general case, all communication is storytelling. Indeed, it’s mostly scientists who baulk at that idea – for people in the media and comms worlds, their surprise is that this is even a discussion.
One of the reasons I believe demonstrations are valuable is that they present ideas from science in a (usually very simplified) narrative structure. You begin with an arrangement of apparatus; something happens; the state of the apparatus has changed.
Demos are stories.
