Think Halloween science!

I’m going to post a spooky experiment every few days from now until Oct.31st. They’re great for school or home Halloween parties, and some even make groovy Halloween Decorations!

This bloody candy experiment takes a few weeks , but is worth the wait! If you start soon, you’ll have gorgeously gruesome rock candy, dripping with sugary fake blood, in time for Halloween.

This experiment requires adult supervision for boiling and handling the hot sugar syrup. Once it’s cooled down, kids can take over.

To make 12-15 sticks, you’ll need the following:

-2 and 1/2 cups white granulated sugar

– 1 cup water

-cake pop sticks or wooden skewers

-red food coloring

1. Dip one end of cake-pop sticks or wooden skewers in water and then roll them in granulated white sugar. The sugar should cover 2-3 inches of the stick. Let them dry completely. These are the seeds for the sugar crystal growth.

2. Boil 2 cups water and 5 cups sugar until sugar is dissolved as much as possible. It should look like syrup. Once it cools, this syrup is your supersaturated sugar solution.
3. Let syrup sit until it is no longer hot and pour into a large glass jar or deep bowl.
4. When syrup is completely cool, set the sugary end of the sugar-seeded cake pops or skewers into the syrup, evenly spaced in the jar. Cover loosely with plastic wrap and let them sit for about a week. Gently move the sticks around occasionally, so they don’t stick to each other and the crystals in the bottom of the glass. If the glass container gets too full of crystals, pour the syrup into a new container and move your stick into the cleaner syrup to grow more crystals.
5. When the rock candy is done, pull them from the syrup and let them dry. Save the syrup.
6. To serve, pour a few cm of your sugar syrup into the bottom of a pretty glass and add a few drops of red food coloring. You can even add a little flavoring to the syrup (like cherry extract.) Stir.
7. Put your rock candy, handle side up, into the glass. Be sure to give your guests napkins, so they don’t drip “blood” all over the house!

How do Crystal Grow?

Like bricks in a wall, crystals are solids formed by a network of repeating patterns of molecules. Instead of the mortar that holds brick together, the atoms and molecules are connected by atomic bonds.

Crystals that share the same chemical composition can be big or small, but the molecules always come together to form the same shape. Table sugar, or sucrose, is made up of a molecule composed of two sugars, glucose and fructose.  Crystals formed by sucrose are hexagonal (six-sided) prisms, slanted at the ends.

The crystals on your rock candy sticks grow from the “seeds” of the sugar you rolled on the stick before you put them in the syrup.

Plants love water as much as vampires love blood. Although they don’t have long thin fangs, they’ve developed a great system for pulling water up through their trunks and stems to their highest leaves using  capillary action.

The kids and I demonstrated how to make them on WCCO MidMorning. Click here to watch.

after 24 hours of “drinking”

Make a vegetable vampire and watch capillary action move colored water through the cabbage creature you created.

To make a leafy vampire, you’ll need:

-head of fresh napa cabbage

-2 large cups,  jars or plasticware containers  large enough to hold the base of ½ of your cabbage

-food coloring

-fruits and veggies to use as eyes and eyebrows on your monster

-toothpicks

-rubber bands or string

 First, fill your two containers ¾ of the way to the top with warm (not hot) water.

Add 10 or more drops of blue food coloring to one container and 10 or more drops of red food coloring to the other .

With a sharp knife, cut the cabbage in half vertically, from the bottom up, leaving the top 10cm or so 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.

Use rubber bands to secure the bottoms of each side of the cabbage and make a fresh cut at the bottom, a few cm up from the old cut.

Put one half of the base of your cabbage in the red water, and the other half in the blue water.

Decorate your two “vampires” with eyes and spooky eyebrows made from olives and peppers (or whatever you have in the refrigerator.)  Secure the decorations with toothpick.

Keep an eye on your cabbage to see how much colored water it’s drinking. Your vegetable vampire will have to drink for 24-48 hours for the best results.

Plants survive by drawing nutrients dissolved in water up into their stems, stalks, trunks, branches and leaves.

Capillary action is the main force that allows the movement of water up into plants. In a narrow tube, on a surface that attracts water, the attraction between the surface and water, coupled with the attraction of the water molecules to each other, pulls water up. Plants are composed of huge numbers of tube-shaped cells that take advantage of these physical forces.

In this experiment, you can see colored water being taken up, via capillary action, into your cabbage.

Imagine how high the water in giant redwoods has to travel to reach the leaves at the top.  In very tall trees, a process called transpiration helps the water overcome the forces of gravity.  Here’s a transpiration experiment you can try at home.