Step 4: Science!
Have you ever wondered how, without a heart to pump liquid around, plants get water from their roots to their leaves and flowers? They exploit certain properties of water to move it against the flow of gravity, through their internal tissue called xylem.
All plants contain a material called xylem which, much like the veins and arteries that move blood around our own bodies, transports water and sap where it's needed in the plant. As water evaporates from the upper parts of the flowers in a process called transpiration, water is sucked up the through the xylem like a straw. Because of the negative pressure at the point of transpiration and a property of water called cohesion (sticking to itself), the water is pulled up to fill the space left by the transpired water.
As this goes on with our experiment over a day or two, the new colorful water is pulled up to the top of the flowers. You can see it in it lacing the flowers, also at the tips of leaves and in the joints of the flowers. The first picture below is the flower placed in the highlighter water fluorescing under UV light. You can really see the fluorescent ink in the petals, as well as the joints of the stems.