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.
<p>hi, my name is magnolia and I was wondering what would happen if instead of using food colors I used different types of highlighters sense you can buy a pack and it has different colors like pink,purple,yellow,blue,and green I want to know if it will still work or if it might not work because I am going to do this project for my science fair project and it is almost due so I wish if can send me a response by tomorrow thanks for reading my request</p><p> sincerely,</p><p> Magnolia </p>
Huh, I think it would work! I'd really love to see some pictures if it does!
In the 70's, I used to do this with my Granddad as a little kid (we also did it with celery to start with. One half in blue, the other in red). We'd hide the carnations in the basement so no one else would know what we were up to. Nanny would get a boquet of carnations with odd colours and we'd have a giggle. The highlighter would have been really cool for my Uncle's basement bedroom with the black lights...lol. <br> <br>Thanks for the memories and bringing back a simple and amusing experiment!
That's neat, I hadn't heard of splitting the stem, could you do that with carnations?<br><br>Thanks for sharing the memories and the kind words!
Not too sure about splitting carnations....try it! The xylem in the celery make it easy. I remember blue and red celery leaves on a single stalk if you split the lower part and put one in red and one in blue water. The cross-section of coloured celery would make an amusing addition to potato salad.
you can split the stem on a carnation. i use to make them for the fourth of july; a red white and blue flower all in one :)
Cool idea! <br>
How long does the effect last?
Until the flowers wilt and fall apart! Even after that, the ones with the highlighter fluid fluoresce under UV light . . . presumably that would fade after a month or two, but I threw them out before then. I'm not one for dried flowers so much.
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 :)
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!
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!
Thanks a lot, that's high praise! If you do make some of these, please post some pictures, I love to see when someone has done one of my instructables in real life!
would the flowers only glow under uv light?
Right. I was trying to think of a way to make them actually glow, but I don't think the flowers would like to drink actual glow in the dark material!
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.
According to wikipedia (I know, not always the best source, but a convenient one), <a href="http://en.wikipedia.org/wiki/Evapotranspiration">evapotranspiration</a> is about groundwater recycling, combining elements of evaporation and transpiration (which I did mention).&nbsp;<br> <br> You're right about the xylem though, I was reading a different site about it last night, I must have gotten bad info.&nbsp; I've reworded this section, what do you think?<br> <br> Thanks for pointing out my errors, I certainly don't want to be perpetuating misinformation!<br>
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.
I'm with you on both counts!
I wonder if this would get more views if you used a UV-lit picture as your main image.
I kinda felt like that might be a good idea, but with the title I wasn't sure . . . I'll switch it up and see how that works. It was having a really hard time last night trying to get a good picture of the colors in the flowers! I think if I'd done the main image against a black background it might have been better, the white background has kind of washed out what color is there.

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