 sound, pitch, that's what this unit is about, pitch is the stuff that we use to make music. How can you go about teaching pitch to students and factors that affect it? Well, I've got a few activities that I'll share with you that will literally make them feel it in their bones and give them an excellent opportunity to investigate the factors affecting pitch, through it identify variables and control those variables so they get fair tests. Take an ordinary elastic band and cut it in half so that we've got a length of elastic to work with. One of these little clips, we'll just fix it to the tabletop and you can hear the vibration. If I stretch it higher, the sound changes and that's the basis for the experiment. There are different ways in which you can get children to explore this. What I often do is get them to use their teeth as the clamp. So they stretch it. The advantage of that is that the sound goes all the way up through the bone structure and in fact they can not only hear the sound, they almost feel it and get a really good sense of the sound that's being produced. If you're demonstrating, I find something that works quite nicely is take a yogurt tub, drill a little hole in the bottom and then just take a pencil or a stick, push the rubber band through that, pull it through a little bit, tie a knot in it and voila, you've made a sounding box to amplify the sound. So that's the simple activity. It's not difficult but what I would get children to engage with now is go and explore it on their own because the pitch that they will hear is very dependent on a number of things and we call them variables. So this is a lovely activity that enables children to identify variables and to explore them, to control them and to have a fair test. So let's have a look at what are the variables that are involved. One is the length of the string. And if we change the length, does the pitch change? It does but you've changed something else as well. Not only have you changed the length but you've changed the tension in the elastic. So you've got two variables and somewhere along the line, they've got to control them. Only one of them must change. So that's the length, what's it like if you do it half that. So clamp it there, so the tension there remains the same, it's only the length that's changed. Another one is the thickness of the elastic, how does that vary? You can use a thin elastic or use a thick elastic. That's another variable. Another one is, but that elastic might be different to that elastic. So it also depends on the nature of the material. Here's an idea, use the same elastic band but let's double it over. Now it's twice as thick. You give it a little twist so that you fix it and then they can tweak that. So these are the different kinds of variables that are involved. Another one that you could play with is what's the amplitude where they give it a little tweak or they give it a big tweak and they should get out of it that the pitch doesn't change but the loudness of the sound changes. Another very important element to your teaching is helping children to see the relevance of what they're studying. How is it what we're talking about today relate to your everyday life? And I think it's not very difficult with something like this because all musical instruments depend on this. So much as we've got a string here that we're vibrating, that's exactly the whole principle of the guitar. You've got strings and why do we get a different note from each one? And you'll see one is thicker than the other. I can tension it and the tension will affect the thing or I can change the length. That's for short, same one, long. So, exactly what we've been exploring is applied there and I would talk that through with children, possibly using any other musical instruments that you do have. Right, I've shared some ideas with you today on how you might approach this topic. I'm sure that there are many ideas out there and I'm inviting you to share them with me and I will find a way of putting them up. I'll give you proper acknowledgement. Just send your ideas to me on this email address.