Impromptu Science Experiment

Maddi brought me some lovely flowers a few weeks ago and we thought we'd try a wee experiment that we had seen before but never done.

We trimmed the bottom of the flowers and instead of just plain water, we put red food colouring in the water.  Check out how awesome the flowers looks after a few days.

With this experiment, the children have discovered how essential the functions of roots and stems are to plant growth.  As the coloured water is absorbed, we can see how the water is absorbed into the plant and how the petals of the flower changes colour.

Technical information:
There are two things that combine to move water through plants - transpiration and cohesion.  Water evaporating from the leaves, buds, and petals (transpiration) pulls water up the stem of the plant.  This works in the same way as sucking on a straw.  Water that evaporates from the leaves "pulls" other water behind it up to fill the space left by the evaporating water, but instead of your mouth providing the suction (as with a straw) the movement is due to evaporating water.  This can happen because water sticks to itself (called water cohesion) and because the tubes in the plant stem are very small (in a part of the plant called the xylem).  This process is called capillary action.