never mind the optics

You don’t have to look too far into the internet undergrowth to find a Wordle these days.  These word cloud images can be a powerful, yet flexible, tool – as shown in Tom Barrett’s 38 ways to use Wordle in the Classroom.  I’ve used this tool before to analyse my own writing for a book chapter.  I found that it helped me to check I had the correct emphasis and was handy for pointing out my repeated use of some words in the piece.

Just before the summer holidays, I thought I might create a series of classroom posters to help pupils identify key vocabulary for each unit of the Standard Grade Physics course, starting with the Using Electricity & Electronics topics for my new S3 & S4 sets respectively.

To generate the wordles, I copied the SQA arrangements for each unit and pasted them into the text box on the wordle site.  I showed the inital results to a test group from the new S3 class and they were not that impressed.

They identified several problems with the output;

• too many words on display (Wordle.net’s default setting is 150 words)
• the random vertical/horizontal word orientation was difficult to read
• words that protruded significantly from the main cloud were distracting
• unappealing colours – particularly so whenever a white background was in use

We started work on these issues by reducing the number of words on display.  The panel felt that 50 words was a good compromise and setting the output preferences to place all words horizontally was straightforward.  Similarly, the positioning of words to avoid any jutting meant remaking the Wordle until it was more pleasing to the eye.  Colour selection, however, was more subjective and it was difficult to achieve a consensus.  Eventually, it was agreed that we would create our own colour palette as agreement could not be reached with the selection provided.

Looking back, I have to agree that the white background is not particularly stimulating and a more inviting word cloud was obtained using a custom palette.  Setting up a custom palette gave a much more visually interesting word cloud, here is the final layout for the Using Electricity vocabulary.

I have to admit the preferring the colour scheme for the Electronics design – it may be the way that the scheme evokes memories of chocolate lime sweets.

I took each of the brightened up designs and uploaded them to a site called BlockPosters.  This site can produce large poster-sized pdf files of any image you upload.  I choose to blow up each image to a 5×2 array – spreading the picture out over 10 sheets of A4 paper.  The printed A4 sheets can then be taped together to create the poster.

So I have 2 posters on my classroom wall now.

They are easier to read than the initial 150 words designs and have colour schemes that appeal to the people intended to use them.  Most importantly, they are being used! When questioning the classes, I see eyes moving towards the posters during “thinking time”.  Not because the answer is on the wall but because pupils know that the vocabulary to scaffold their response will be.

The dust (sorry!) is starting to settle after 2 fantastic nights of participation in the annual Perseid meteor shower.  The event hasn’t actually finished just yet but the number of meteors per hour will fall rapidly now that we have passed peak activity.

So what was it all about?  I’m no astronomer, nor am I presumptuous enough to think I provide a decent explanation.  Basically, our planet just passed through the debris trail left by a comet called Swift-Tuttle.  You can find out more about the phenomenon here.  What I have found astonishing is the sheer number of non-astronomers (myself included) who have been following events and staying up late to view these blazing trails of light as they stream across the night sky.  How do I know that so many people have taken part? Well, that would be down to Twitter.

Many astronomers have seized the publicity available to them through the International Year of Astronomy 2009 to promote their work/research/hobby to people who have never had any dealing with astronomy before.  The 365 Days of Astronomy podcast dedicated an entire episode to the Perseids just before they arrived.  While these would have contributed to a raised awareness, they are not sufficiently mainstream to attract the unprecedented interest surrounding this year’s event – this is where Twitter comes in.

In the UK, a local astronomy group called Newbury Astronomical Society, who tweet from the @NewburyAS twitter account, seized the initiative by setting up the #meteorwatch hashtag for the Perseids event.  The tag caught on and hundreds of people shared their experiences during the shower by tweeting with that hashtag, taking it to 4th place in Twitter’s trending topics.  The organisation of the Newbury club even drew the attention of the BBC (click link on that page to see video footage) who visited “the bunker” during the first evening.

While the south of the UK enjoyed clear skies on the first evening, I was not so lucky.  As there was no way I could see the meteors, I tried to detect them using a very basic radio technique instead.  I connected an FM antenna to the back of an old Pioneer receiver unit and fed the output into a Griffin imic (with RCA to 3.5mm jack adapter) that was plugged into the usb port of a laptop.  The Griffin components were essential to convert the RCA HiFi electrical connections into a standard computer connection.

I tuned the radio to the lowest clear FM frequency available (87.5MHz) and used a virtual chart recorder package call Radio SkyPipe to record the data.  The recording software is quite straightforward and would be a good introduction to signals and measurement for senior pupils, such as those undertaking AH Physics investigations or the new Science Baccalaureate, as it requires several calibration & signal nulling steps before use.

Unfortunately I didn’t capture any exciting data although there was a curious low frequency amplitude modulation (see below) on the signal that I could not explain.

On the second night, I decided to leave the setting up of hardware for radio astronomy to the professionals and concentrated on looking for streamed data from the web.  I found this site broadcasting from Tavistock in Devon.  I downloaded the BS-Tuner application and pasted in the url of the broadcast site.  To my surprise I heard streaming FM static coming from the laptop.

Every now and then this static was pierced by an eerie scream as radio waves were reflected back down towards the Tavistock antenna by the ionised wake of each meteor.  The signals varied in volume, duration, clarity and complexity but due to their unpredictable nature it was difficult to record one.  However I have attached one of the sounds I captured and encourage you to play it using the flash player below.

I was disappointed to view just a single Perseid at around 2.30am last night, the weather just wasn’t right for it.  However, without those clouds I’d never have considered the potential for homemade radio astronomy.

A Nasa podcast on the Perseids is also available.

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