Magic Teaparty
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Magic Teaparty
Dorchester Middle School
Download film (right-click)Artistic/Creative , Chemistry , Demonstration , Drama , Primary
A neat trick using sodium polyacrylate — but don’t drink the tea!
Director's Notes:
When you first see this trick it’s hard to believe — you pour water into a cup containing a small amount of water-retaining gel granules, swish it around for a few seconds, and then turn the cup upside-down. The gel absorbs the water and swells up, locking the water away. You can buy the granules at garden centres if you’d like to try it for yourself, but do make sure you don’t eat them!
The granules are sodium polyacrylate, which can absorb up to a thousand times its own weight in water. Amazing. You’ve seen the nappy adverts which boast of absorbing huge amounts of… umm… liquid? That works because the nappy pads contain powdered sodium polyacrylate. Aren’t you glad you know?
The film itself was a deliberate attempt to inject a little glamour into SciCast, which all too often ends up in a dingy school lab. A little work on the set went a long way, there’s a costume of sorts (actually a giant metallic helium balloon that was lying around), and even some lighting to punch up the image. Brilliant.
SciCast Notes:
This team set themselves a much harder challenge than they realised, in that having three people on camera is unbelievably more complex than two, let alone one. But they captured the story nicely, and you can just about see what’s in the cups, though if we’re being picky some even tighter close-ups wouldn’t have gone amiss.
The film is also notable for having used an unusual part of the SciCast kit, a Fig Rig. This is a steering-wheel shaped camera support that helps keep small cameras steady when they’re being handheld. We picked one up cheap, and while it’s a bit bashed-around it works perfectly.
It really came into its own here because the camera operator was a wheelchair user. Holding a heavy camera all day is tiring, but the Fig Rig allowed her to rest it on her lap and still have the lens positioned at a good height. Then the wheelchair itself produced the ultra-smooth ‘tracking’ shot you see in the finished film, where the camera pushes into the action. Great work.
— Jonathan