Picture the scene you are explaining something to your students. You have a practical activity to enhance the learning but the lesson still feels a little flat. You try to do a demonstration that has never worked for you but it doesn't work - predictably- so you put a video of someone doing it correctly on.
You get annoyed at this person on YouTube or whatever being able to do something and make it seem so easy. In this case lighting a Bunsen burner with a Van der Graaf generator.
So you step into the plastic box to isolate yourself. Get a shock on the VdG when you put your hands on it and charge yourself up. After a minute you ask a student to turn the gas on and with one slightly shaky hand you start to touch the Bunsen. You get shocked but are now determined. Your class is drawn in with you because they know you have never done this before. You keep going and after what seems like an eternity (a whole 30 seconds) a flame appears!
In stead of professionally smiling and explaining what has happened your euphoria gets the best of you. You start to dance around the room like a Leprechaun on drugs, the students are laughing and cheering and then you realise one of them has been filming you.
Yet this isn't some sinister students getting one up on a teacher. This was a class who genuinely wanted me (this happened on Tuesday) to succeed. The student e-mailed me the video (which I would love to share but can't as students are in view). It reminded me of the power of a good demonstration. Especially ones that show that you love your subject or that you are showing them something special.
Now people who read my blog know I love the practical nature of science, especially letting students discover scientific principles through experimentation - a practical that doesn't work is just as useful as one that does as students can evaluate it and gain skills experience - but I often neglect the demo as being a second class of practical.
However the success of Tuesdays demo is making me reevaluate my thinking on this area of my teaching.
Especially as the next lesson in my series was to do with the dangers of statics. The the students had spent the next few nights watching my lighting of a Bunsen on FB meant that they all knew the dangers of sparks in areas with fuel vapours (and yes I played Sparks 'this town aint big enough for the both of us' in the lesson).
So I am now going to try and add more demonstrations into lessons especially ones that will either stretch me as a practitioner or link some concepts together. Well that is the aim anyway!
One thing to add to this is that showing work or how to draw things as a demo is just as good. I often use or have used a home made 'visualiser' to show how to draw graph axis in BTEC classes.
For those who don't know the cheapest way to make a visualiser is to use an external webcam (about 2 quid) and a retort stand with a boss head (which you can get for under 15 quid on ebay!). Much cheaper than a several hundred pound visualiser and does just the same job in my opinion.
And just for fun here is a screen grab of my dancing!