What color would you like your celery? Part 2 – What did you found out?

Earlier I showed you how you could use food dye to investigate how water moves through celery.

Did you do it?! If you did, good on you! What did you find?

This is what I saw.after blue celery

The first photo (on the left) shows the celery leaves after an hour in the food colouring and water. The other two photos were taken after a whole day. If you look closely you can also see a line of blue going up the stem.

The leaf got bluer the longer it sat in the blue water.

Why? Remember how water travels up tubes through the plant to the leaves? The blue dye is carried in the water, but it can’t get out of the leaf so it stops there. The longer you wait the more dye has stopped in the leaves, and that makes them go bluer.

When did you notice the leaves start to go blue? It happened quite quickly. The water travels quickly up the plant.

If more and more water goes into the leaves why aren’t they getting wetter? Or perhaps bigger?

The leaf only keeps as much water as it needs. The water that’s drawn up into the leaves escapes through tiny holes in the leaves. More water moves up through the stem to take its place.

Why can’t you see this water escaping? The water that escapes out of the leaves has evaporated – that means it has turned into a gas. Water gas is called water vapour and it’s invisible.

This is what I saw when I cut across the stalk. I cut the stems every 3 cm.

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What color do you like your celery? A classic experiment for kids

Before we do things with silverbeet leaves (see my last post) I want to do a popular experiment to learn about how water moves through plants.

Have you ever had a vase of flowers? What happens if the flowers aren’t in water? They droop and wither pretty quickly.

Why is that?

Plants need water to live, in fact they are mostly made of water. Plants are always losing some of that water into the air.  They need to suck up more water through the stem to replace the water they’ve lost or they droop, and eventually die.

This is a bunch of celery. Or you might call it a head of celery.

This is a bunch of celery. Or you might call it a head of celery.


  • Celery with leaves
  • Sharp knife or scissors
    • a grown-up to help if you’re not allowed to use the knife on your own
  • Glass or jar of water
  • Food coloring


  • Food colouring can stain things so make sure you protect yourself and your stuff from spills and splashes. You could put newspaper on the table. You could wear a raincoat, art smock or old clothes.


First read through these instructions and try and guess what will happen.

  • Add a few drops of food colouring to the water and mix them together
  • Get a grown-up to help if you’re not allowed to use a sharp knife – yes now
  • Cut the celery stalk straight off the bunch if you can, or cut the end off the stalk if it’s already been cut off the bunch
  • Put the cut end of the celery in the colored water
  • Wait and watch
  • When you’ve finished, cut the stem and see what the end looks like. Cut some slices. Break the celery stick and have a look at the structure inside.


0 min blue celery zero min 10-jan-15-2

This is my stick of celery just after I put it in blue water.


And more importantly – I want you to think about why that happens.

You could use the websites below to find out what happened when other people did it, but I guarantee you’ll have more fun if you do it yourself.

I’m going to give you a chance to do that before I talk about what happened to mine!









“Céleri”. Licensed under CC BY-SA 3.0 via Commons – https://commons.wikimedia.org/wiki/File:C%C3%A9leri.jpg#/media/File:C%C3%A9leri.jp


This is cross-posted to Real Science and Other Adventures.



Fun with plants – Refraction

Let’s do a simple experiment. To prepare I’ve cut two silverbeet leaves from the garden. (You might call this chard – it’s the same thing.) Each goes in a glass. One glass is filled with water and the other glass is dry.

silverbeet refraction 2

Hey wait a minute!

Do you see that? See how the stalk in water doesn’t seem to connect to the stalk in the air? It’s called REFRACTION.

silverbeet refraction closeup

It looks bigger in water too.

silverbeet refraction closeup 3

We don’t always see things as they are!

When you see something – like a leaf – it’s because light has hit the leaf and bounced off it, onto your eye. Light travels. Have you heard of a light year? That’s how far light goes in a year. It’s a very very long way – light is very fast.

In the picture you can see through the water because light went through it. The same with the glass.

Not only does light travel, but it can change direction. Light can bend when it moves from air into water, or water into air. (Click here for a simple diagram that shows you how that works.)

You can do this for yourself, maybe with a spoon in a glass of water.

See how the bricks curve behind the glass. That’s refraction too. You can find out more about refraction if you’re interested. There are some links below.

Anyway – that’s not why I cut two leaves.

Why did I cut two?

Can you guess what I’m going to do with them?

Find out more next time.



There are quite a few! They include chard, Swiss chard, silverbeet, perpetual spinach, spinach beet, crab beet, bright lights, seakale beet, mangold and spinach. This list is from the wikipedia entry for chard: https://en.wikipedia.org/wiki/Chard








Cross-posted to Real Science and Other Adventures