Make Multicolored Carnations . . . With Science!




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Inspired by user NurdRage's video of how to make your flowers glow under UV light, I revisited an old science experiment from middle school.  India and I turned a bland spray of white carnations into this lovely bouquet of multicolored flowers, just in time for Valentine's Day.

So come along and join us, as we have fun and learn something interesting about plants in the process!

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Step 1: Supplies

This is a very cheap little science experiment, you probably have almost everything you need already around the house:
  • 6 vases/cups/jars/etc
  • Liquid food coloring
  • A highlighter you don't mind destroying
  • Scissors
  • White carnations--I found a spray of white mini carnations at Albertson's for $3.33
I'm told that carnations work best for this experiment, but I've not tried another kind of flower.  Has anyone out there tried a white rose or some other kind of flower?

You'll also need to have a black light or some UV LEDs for the highlighter part of the experiment.

Step 2: Prepare the Containers

Fill each of your containers about half full of water.  Liquid food coloring usually comes in a package of red, blue, green and yellow, so in the first four jars squeeze out a generous amount of each color--especially yellow, it's usually kind of pale.  I bought a package of food coloring just for this purpose, so I used the whole container.

In the fifth jar, remove the ink sponge from the highlighter and dump the whole thing in the jar.  NurdRage just used a few drops in his video, but hey, I figure if you're gonna do something like this, why not go whole hog?

The sixth jar is, of course, left untouched as your control.  This is science after all!

Step 3: Add the Flowers

Split the carnations into six groups and add them to each container.  At this point, cut an inch or two off the bottom of each stem, at a 45 degree angle.  Supposedly, it's best to do this underwater, so do it in the jars if you can, or in a mixing bowl, the sink, etc.

Now all that remains is to leave the flowers in their vases overnight (or longer) to let capillary action do its work!

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.

Step 5: Final Thoughts

Thanks for joining us on this little trip to Science Land!  Praise be to the mighty NurdRage for reminding me about this cool little experiment.  It's fun for kids, looks great, and teaches just a bit of the scientific method of inquiry.

If you enjoyed this, don't forget to rate, comment, and subscribe!

As always, if you make your own version of this, post a picture in the comments and I'll send you a digital patch!

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    28 Discussions


    4 years ago on Introduction

    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



    2 replies
    johnny test sc

    3 years ago

    i did this project it was sooooooooooooooooooooooooooooooooooooo coooooooooollllllll


    3 years ago

    Wow, I haven't thought about this in years! When I was a little kid my mom used to do this with daffodils and blue ink. Turns them green!

    1 reply

    8 years ago on Introduction

    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

    Thanks for the memories and bringing back a simple and amusing experiment!

    4 replies

    Reply 8 years ago on Introduction

    That's neat, I hadn't heard of splitting the stem, could you do that with carnations?

    Thanks for sharing the memories and the kind words!


    Reply 8 years ago on Introduction

    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.


    Reply 7 years ago on Introduction

    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 :)


    Reply 8 years ago on Step 5

    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.


    8 years ago on Step 4

    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!! if you mind :)

    2 replies

    Reply 8 years ago on Step 4

    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!


    8 years ago on Step 4

    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!

    1 reply

    Reply 8 years ago on Introduction

    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!