Step 4: Science!

Picture of 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.
IETMN4 years ago
would you mind to send the pdf to my email? I know this shouldnt be done but Im not a Pro and I love your experiment!! stefymel@hotmail.com if you mind :)
depotdevoid (author)  IETMN4 years ago
Well, you're right, it's not supposed to be done. Tell you what, go out and buy some carnations and some food coloring, do the experiment, post some pictures here, and I'll send you a 3 month pro membership. Then you can download the pdf yourself!
cmartin-14 years ago
I love the science you are teaching while still doing something neat. This sounds like a great summer project for my kids! I was also glad to see you took someones science comment and answered nicely. To many times people write something nasty back before thinking. I am following your Instructables now so I can teach me kids a few neat things over the summer. Thank you again!
adamjoe864 years ago
Your scintific principles behind this experiment are slightly off. The main force behind water movement in plants is through evapotranspiration, capillary action isn't strong enough force to draw water into trees. Evapotranspiration takes place when water in the leaves, and flowers is transpires through pores called stomata. The water is typically taken up through the roots (in this case directly from the jar into the stem) and travels through the xylem elements (not capillaries) into the tissue.
depotdevoid (author)  adamjoe864 years ago
According to wikipedia (I know, not always the best source, but a convenient one), evapotranspiration is about groundwater recycling, combining elements of evaporation and transpiration (which I did mention). 

You're right about the xylem though, I was reading a different site about it last night, I must have gotten bad info.  I've reworded this section, what do you think?

Thanks for pointing out my errors, I certainly don't want to be perpetuating misinformation!
It sounds much better. Thanks. I just don't like bad information being spread around (like on wikipedia). I've found that wikipedia is more useful as a place to get preliminary information but it's best to check their sources.