Kids will love to learn how plants drink by creating cabbage monsters that suck up colorful water.
Plan ahead, since your “vampires” will have to sit in colored water for 24-48 hours before you see a dramatic color change. Adult supervision is needed to cut the cabbage.
What You'll Need
- A head of fresh napa cabbage
- 2 large cups, vases, or jars, large enough to hold the base of 1/2 of your cabbage
- Food coloring
- Fruits and veggies for decoration (olives, berries, and red peppers work well)
- Toothpicks
- Rubber bands or kitchen twine
How to Make Veggie Vampires
Step 1: Fill your vases or jars three-fourths of the way to the top with warm (not hot) water.
Step 2: Ask your child to add 10 or more drops of blue food coloring to one vase and 10 or more drops of red food coloring to the other vase.
Step 3: With a sharp knife, make a fresh cut on the bottom of the cabbage stem, by cutting 1 or 2 cm. Then, cut the cabbage in half vertically, from the bottom up, leaving the top 10 cm or so of the cabbage intact, so the two pieces are still attached at the crown. If possible, try to cut down the middle of one of the big leaves.
Step 4: Using rubber bands, secure the bottoms of each side of the cabbage and make a fresh cut at the bottom, a few centimeters up from the old cut.
Step 5: Put one half of the base of your cabbage in the red water, and the other half in the blue water. Ask your child what hethinks will happen to the water.
Step 6: Have your child decorate the “vampires” with eyes and spooky eyebrows made from olives and peppers (or whatever you have in the refrigerator). Pin the decorations into the cabbage with toothpicks.
Step 7: Have your child check the cabbages every few hours to see how much colored water she's drinking.
The Science Behind the Fun
Like vampires, plants prefer a liquid diet. Plants survive by sucking nutrients dissolved in water up from the ground into their stems, stalks, trunks, branches, and leaves.
The main force that moves water up into the plants is called capillary action. Cabbages, which are plants, have lots of tube-shaped cells that take advantage of these physical forces.
In this experiment, you can watch colored water being taken up, via capillary action, into a cabbage.
You can find more experiments like this one at kitchenpantryscientist.com, and in my books Kitchen Science Lab for Kids (Quarry Books) and Outdoor Science Lab for Kids (Quarry Books).
© Quarry Books, 2016/Kitchen Science Lab for Kids
Featured Photos Credit: © Quarry Books
