Polystyrene Tile Gliders

What you need

1. A polystyrene ceiling tile. You can buy these in packs of ten from DIY shops - they're quite cheap, and each tile makes two gliders. Go for as smooth a surface as you can find - some tiles have ghastly patterns on them.
2. A few paperclips.
3. Sticky tape.
4. A cutting mat (or large sheet of cardboard), craft knife, long ruler or straight edge, and somebody who's not likely to hack their own leg off by accident.

What you do

1. Cut the tile from corner to corner. Be very, very careful here - as ever, a sharp knife will be easier to work with, but also easier to remove your own fingers with.

2. Equally carefully, cut a large triangle out of the middle of the long edge. Each side of the triangle should be about 10cm long, but it's not critical. You'll end up with a shape that looks a bit like a stealth bomber, only much smaller, white, made of polystyrene, and costing about $2bn less.

3. The 'front' is the right-angle corner, so the 'wings' are the... er... bits sweeping back on either side.

4. Here's the tricky bit: you need to bend up the last 10cm of the wings, just a little bit. You'll find you can gently curl them against the table - gently, to avoid snapping them. Half a centimetre of bend is plenty, but try to get it even on both sides.

5. Finally, tape three or four paperclips under the nose of the glider. You'll need to experiment to see how many works best for you.

6. To launch the glider, hold it from the triangle cut-out, pinched between your thumb and forefinger. Point the nose just slightly down, and gently push the glider away from you, along the line of its nose. With luck, it'll waft gracefully off across the room.

What's going on

If your glider flies at all, you'll probably notice that it flies spectacularly well. Head to a school hall or gym, and see just how far it'll go. Quite likely, it'll go much further than a paper dart would, and possibly it'll go further than the room does.

A flying wing is a remarkably efficient aerodynamic shape. The wing area is huge and the weight is low, which means it can fly quite slowly - which causes less drag. Also, your glider is stable not because of a clumsy tail or fins, which would add drag, but because of the way vortices of air form over it. Bending the wingtips up is crucial to help shape those vortices.

You can find small but useful pictures of the glider from The Big Bang, here:

http://www.granadakids.com/bigbang/ser56/show6item4.html

We also made a winch launch system for the gliders, which you'll find here:

http://www.granadakids.com/bigbang/ser56/show6item4_winch.html

And if you want to know more about flying wing designs, this is a good place to start:

http://en.wikipedia.org/wiki/Flying_wing

Special Safety Advice

Take care not to injure yourself with the sharp knife!