I had a well thought out and well structured post all typed up, but a WordPress error caused it to disappear into the ether, despite having clicked on Save Draft, my post is nowhere to be found.
The short version of what I had typed is that after realising I needed to float over the top of my videos to allow more space to be used for whatever it is that I am showing, I ordered a green screen (chroma key) kit, which arrived a few days ago. Having today off provided me with an opportunity to experiment, and I have been playing around with it for a little while now and have put together a very short test video.
It is certainly not perfect, I need to work on getting the lighting right behind my torso to prevent the shadowing that occurred, but I am reasonably happy with it as a first effort.
I would love to hear from anyone who is using chroma key techniques in the classroom, and what obstacles you have come up against, and what strategies you have used to circumnavigate those obstacles.