I love the smell of traffic in the evening

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?

Collapsing Can

The collapsing can demo is one I loved seeing for the first time when I was at school, although my teacher used a tin with a screwed down lid which took a little more time to cool down. In some ways I prefer the version using a can with a screw lid because the additional waiting time makes for an even more dramatic “collapse”. Doing the demo with a drink can is of course far cheaper (and I think, more reliable as it doesn’t depend on the lid being screwed down properly) and I suspect this is why the approach we use in our video has become far more widespread in schools.

I like the demo a lot but, as I hope we’ve managed to convey in the video, I think we need to be careful how and why we use it in our lessons. This is a really fantastic demo for using the Predict, Observe, Explain (POE) approach as the explanation of what’s going on is not entirely straightforward – there are a couple of things relating to the behaviour of particles and the action of forces that need to be considered and this can lead to some really interesting discussion with students, providing they’re familiar with the relevant concepts.

We’ve suggested in our video that the collapsing can demo can be used in conjunction with another demo, as a way of “scaffolding” (I really hope I’ve used that term correctly – I think this may be the first time I’ve used it in writing in this context).

Once you’ve done the demo live in class, you’ve got the perfect justification for showing your students this video of a rather more spectacular demonstration of the same physics at work:

Get Set Demonstrate logoThis 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.

Magic in the classroom: The Iodine Clock

As well as being a science geek, I’m a magic geek. I’m not sure if anyone’s done the research on this, but I suspect those are two groups of people where there’s a significant overlap. I’ve got an entire live science show I do based around my love of magic and my somewhat lame attempts to become a magician and I include this demonstration as a highlight in the show. Like many of the demonstrations we’ve filmed, I don’t think video can do justice to how amazing it is to see in real life – it appears to be genuinely magical and always gets an “ooh” from the audience.

I’ve used the iodine clock in class purely for the effect it has of enthralling my students, but, as I hope the video shows, it can be used to achieve particular learning objectives. Mind you, I hope it’s clear that we at sciencedemo.org think “enthusing students” can be a sufficient justification for using a particular demo, if you’re going to take that enthusiasm and use it to help students get more out of your science lessons in general.

Get Set Demonstrate logoThis 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.

Universal indicator-a-go-go

Spotted on Twitter:

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.

Curved space-time

I love this demo, but it’s one of those oddly bimodal ones – you can interact with it in two different ways:

  1. You throw marbles at it yourself, and stare at them. This is delightful, though rarely very informative.
  2. You’re led through a structured exploration by a demonstrator, as here. This is informative, but less delightful.

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.


Flame colours

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.]

Acoustic levitation using standing waves

Most physics teachers will have to demonstrate standing waves at some point in the school year and there are a number of standard demonstrations which can be done with school lab equipment. When teaching about them, I also show videos of standing waves I can’t recreate in the classroom and the one above is a lovely addition to my resources for this topic. This video also reminded me of a piece of art I saw at the Tate Modern several years ago – Kinetic Construction (Standing Wave) – which was the first time I saw a Physics demonstration presented as “art”.