The method is simple. Roll the blotting paper or sheets of kitchen roll into a tube that you can insert into the jar.
Wedge a runner bean seed between the blotting paper / kitchen roll and the side of the jar.
Add about an inch of water to the bottom of the jar.
The water will travel up the blotting paper or kitchen roll, and the bean will begin to germinate. Keep the water level topped up, and the children can watch as the bean produces a whole root system at a phenomenal rate.
Ultimately they can then pot this bean on into a plastic pot of compost, take it home, and later plant it out in their own garden with a bamboo cane for support. The exciting thing will be them being able to eat their own beans at the end of the experiment.
From : mistyhorizon2003