Hi everyone!

That's a really interesting question!

Let's start with the first part of the question: why did the celery stick change color when you put it in colored water? A celery stick is full of water! As part of a plant, it has a series of tubes that run throughout it that transport water. When you put the celery stick in the water, some of the water in the celery left and went into the cup and some of the water in the cup moved into the celery. This is called diffusion, and it is when particles, like water and the dye, move around and become evenly spaced. So, that's how the colored water got into the celery!

The second part of the question is: why could you see the celery change color? Well, celery has very thin cell walls, and when the colored water got into the celery, you could see through the celery walls and see the colored water. One reason you could see this so well is because celery is mostly water!

The third part of the question is: why didn't the same experiment work for plants? There are several possible reasons why this might be so. First, you guys seem to have watered a living plant. This means that the water was taken up through the roots, which are very fine. It is possible that the color didn't make it all the way up to the flower portion! It is also possible that you needed to add more dye to see an effect. Try it again, but with more coloring! However, a more likely explanation lies in the flower choice. The reason you could see the colored water in the celery is because the celery cells are very thin and celery is mostly water. It is possible the flower has thicker cells and so you couldn't see the water through them. When students try to color flowers, they usually use carnations, since those flowers have very thin cells and you can see the color through the petals.