A Scientific Experiment with Celery and Food Coloring

distinct color

How to set up a simple Scientific Experiment with Celery and Food Coloring :: Tinkerlab.comWhile I’m an art educator by trade, having small people pulling at my pants has turned me into a mini-alchemist who’s suddenly found herself reading books to her kids about Galileo (The Magic Schoolbus and the Science Fair Expedition) and brewing all sorts of concoctions in our kitchen (vinegar and baking soda, anyone?).

This project is easy to achieve with basic kitchen materials and it’s embedded with all sorts of opportunities for introducing the scientific method (in short: asking scientific questions, making predictions, and conducting an experiment).

 

science food coloring celery experiment

Materials

  • Celery with leafy tops
  • Clear glasses
  • Water
  • Food coloring

The Experiment

N poured water into three glasses. about 3/4 cup in each.

Then she added a few drops of food coloring — 5-8 drops, but who’s counting! — into the glasses and stirred with a piece of celery, which was left in the glass. And then we talked about what might happen if we left the celery in the colored water for a while.

science food coloring celery experiment

We oohed and ahhed over the lava-lamp effect of the food coloring as it hit the water.

We started off with red, yellow, and green, but N really wanted to mix colors and added blue and red to the green water (far right). We revisited our earlier discussion and made predictions about how the celery might change.

While waiting for something to happen, I chopped the celery heart off the bottom of the stalk and set up a printing activity.

N humored me by making a few prints and then asked if she could play with colored water. Totally!

While I only have one photo of this, it was probably the highlight of the afternoon.

capillary action

When we checked the celery a couple hours later, this is what it looked like. I put a leafy top next to it so you can see how subtle the change is. Hmmm. While I could see the change, I wasn’t sure it would make a big impact on my daughter. And then I realized that I should have just put the leafy parts in the water for a more dramatic result. Done!

A few hours later the blue/green had the most pronounced shift, but the red and yellow were visibly different too.

capillary action

Here’s a side-by-side comparison of the red and blue-green died celery tops, about 16 hours after the stalks had been sitting in the water. N seemed to appreciate the difference, but wasn’t nearly as impressed as her dad and I were.

The science behind the art

Plants need water to survive and they draw water up from their roots through their capillaries. The capillaries are hollow and act a lot like a straw. Adding color to the water helps us visualize this usually invisible process.

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Painting on Ice Cream

painting ice cream

If you live in the U.S., there’s a good chance that you’re in the middle of a terrible heat wave. While I can’t make it cooler (sorry about that), I’d like to offer up this cool lesson in color mixing…and it all happens right on top of a chilly scoop of ice cream, sure to help you forget the heat for at least 5 minutes.

Tools

  • Vanilla Ice Cream
  • Food Coloring. Because I like to keep it natural, my new favorite food coloring is India Tree Liquid Natural Decorating Colors. They’re pricier than supermarket food coloring, but they last a long time, the colors are wonderful, and you’ll feel good about feeding your family with natural coloring.
  • Bowls
  • Ice Cream Scooper (optional)
  • Assorted sprinkles and syrup (optional)

Drop food coloring directly onto the ice cream.
Blend it around in whatever way you like.
After you marvel at the rainbow colors on your ice cream, pour on the jimmies, rainbow sprinkles. colored sugar or syrup. Yummy and cool.

Enjoy!

Dry Ice Experiment

DSC_0036

Dry ice is a favorite mysterious Halloween material, perfect for spooking up a witch’s cauldron, but did you know that you can experiment with it too?

Dry ice is so cool (couldn’t resist!), and makes for a fantastic (ventilated) kitchen or outdoor experiment. Have you ever worked with it? The big caution is that you don’t want to touch it less it burns your skin. Got that? So it has to be handled with tongs and/or insulated gloves.

Read up on  the cautions of using dry ice before proceeding, and always use your best judgment. I went through all the warnings with N, and the dry ice earned a great deal of her respect. She kept asking questions about how ice could burn us (it wouldn’t make sense to me either if I were her age), and was very curious about how it “smoked” on its way from our porch to the kitchen.

In case you’re wondering, I think it’s smart to introduce kids to “dangerous” things. They’re naturally curious about how the world operates, and given the proper instructions and parameters these introductions can give them a good foundation for critical and creative thinking. Have you heard of the The Dangerous Book for Boys or The Daring Book for Girls? I have a copy of the latter that I know N will love when she gets to be a bit older.

I found the dry ice at our supermarket, and asked the manager to help me pack it up. They come in big bags (perfect for cooling a fridge full of food, but far too much for this experiment), and I understand that they may break smaller pieces for sale…it sells by the pound at our market. To do this experiment, we used two pieces, each the size of a button mushroom.

I filled the bottom of this metal travel mug with about a cup of warm water, and dropped a piece of dry ice in with kitchen tongs. The ice makes a surprising sound when handled by the tongs!

The smoke is perfectly okay to touch.

And blow.

Then we got fancy. N squeezed some dish soap into the mug.

Surprise!

And it got even more exciting with the addition of red food coloring.

And green, blue, and yellow food colorings, too!

This project is great for encouraging curiosity, setting the groundwork for scientific investigation (observation and experimentation), and building creative confidence. A+ in my book!

The Science behind Dry Ice

Dry Ice is frozen carbon dioxide, which dissipates into carbon dioxide gas when it melts. It’s called Dry Ice because it turns directly into a gas from its solid state, without ever becoming a liquid, and therefore there’s no puddle of water in its melted state. This process is called sublimation. Also, Steve Spangler Science is my new best friend, and it’s where I gleaned tons of good information for this post. If you like science experiments, do check this out.

More Ideas from Tinkerlab

Get more Halloween ideas on my Halloween Pinterest Board.

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