Who said science couldn’t be fun? This little experiment is the perfect activity for kids to learn about plant biology, the basics of setting up a controlled experiment, and creating pretty décor as a result!

What you’ll need

  • White carnations
  • Liquid food colouring – pick a variety of colours
  • Cups
  • Observation sheet



  • To start with, trim down the stems of your flowers so that they sit comfortably in your cups or glasses. Try to make the stems the same length.
  • Fill each empty cup about halfway with water.
  • Put between 10-15 drops of food colouring into each cup. Make sure to put different colours into each cup, and once you’ve picked a number of drops keep it consistent.
  • Add at least one carnation to each cup of coloured water.


Create an observation sheet where your kids can record their observations at different intervals, including a section for ‘what I think will happen’, ‘what I can observe’ and a final ‘what I learned’ area. This allows them to measure what happens to the flowers and compare their learnings to their expectations.

Now sit back and observe the flowers changing colour! They will start to see some changes after a couple of hours, at which point some of the flowers should start to show faint streaks of colour along their petals. After a day or two the colours will continue to become more vibrant. Set an end date for your experiment, a few days should be long enough to get the full impact of the changing colour of the flowers.

After the results have been written up try and mix it up by changing certain variables. There are plenty of ways to adapt the experiment, such as increasing the dosage of food colouring to try and achieve a more saturated colour, introducing more flowers to each cup, or trying different flowers to compare with the carnations (like roses) to see which one takes the colours better.


So why do the flowers change colour?

Plants drink water from the ground up through their roots, up the stem and into the petals of the flower. Though our flowers don’t have roots, they are still able to pull water up from the cup into the stem and up to the petals, carrying with it the coloured dye. This ability is called capillary action, where liquid can flow in narrow spaces in spite of gravity.

Colour changing flowers


For more fun learning activities check out funlearningforkids.com