"Cut out a flower shape from smooth writing paper, colour it with crayons and fold the petals firmly inwards. If you place the rose on water you will see the flower petals open in slow motion.
Paper consists mainly of plant fibres, which are composed of extremely fine tubes. The water rises in these so-called capillary tubes. The paper swells, and the petals of the synthetic rose rise up, like the leaves of a wilting plant when it is placed in water."