Goblin goo can take a solid or liquid form, both of them gruesomely gross.

How can you have a Halloween party without Goblin Goo? Or Magic Potion? Or fake blood?

That’s the message from Liz Heinecke, aka the Kitchen Pantry Scientist of Edina, Minn., who creates her magical concoctions at home with her three children, ages 5, 9 and 10. A former medical researcher who has a master’s in bacteriology, she now cultures more germs than ever, as she notes on her website, www.kitchenpantryscientist.com.

Her experiments are well suited for the young crowd at a Halloween gathering. So let’s break out the beakers (no safety glasses needed here).

—Goblin goo: In a medium-size bowl, mix together 1 cup of cornstarch and ½ cup water, with a little food coloring (purple, green or red would be Halloween-oriented). Use your fingers or a spoon to combine them. Goo will be the consistency of syrup. Messy alert!

When you roll the mixture into a ball, it will act like a solid. When you run it through your fingers, it will act like a liquid.

Science principle: Cornstarch goo is known as a non-Newtonian fluid, which doesn’t have the normal properties of either a liquid or a solid. The cornstarch molecules are like long ropes. When left alone, they look like a liquid; when you move them around, or "agitate" them, as scientists describe it, they act like a solid.

—Magic potion: Parents may want to do the prep for this in advance. Chop a head of red cabbage into small pieces and add it to a pan with enough water to cover it. Boil the cabbage uncovered for about 15 minutes, stirring occasionally. Let it cool and strain the juice into a jar or bowl. (Save the cabbage for a meal.)

Pour about ¼ cup cabbage juice (this is the "magic potion") into two clear glasses or bowls and set them on a white piece of paper so you can watch as the color changes.

Add 1 tablespoon baking soda to 1 glass of potion (this will create a base solution). To the second glass, add a couple of tablespoons of vinegar or lemon juice (this creates an acid mixture). Watch what happens.

Science principle: The pigment that makes red cabbage red is an acid/base indicator. Vinegar turns the mixture pink because it’s an acid, while baking soda turns it blue or green, because it’s a base. Mix them both together for another reaction (you’re creating carbon dioxide gas and guess what that does?).

—Wiggly worms: Cut Gummi worms with a kitchen shears into thinner long strips. Soak them in a solution of 2 tablespoons baking soda mixed with 1 cup water for about 15 minutes. Take the worms out of the solution and drop them in a container of vinegar. There will be a chemical reaction that will cause the worms to wiggle. Science principle: When you mix baking soda (sodium bicarbonate) with vinegar (acetic acid), a chemical reaction occurs, forming carbon dioxide bubbles which make the worms float and move.

—Bag of blood: Fill a heavy-duty quart-size zip-top plastic bag with water and a few drops of food coloring. Then press the seal on the plastic bag. Slowly poke several wooden skewers completely through the bag, from one side through to the other, avoiding the part with air in it. (Advice: Put a bowl underneath the bag, just in case.)

Science principle: Plastic is a polymer with molecules that form a seal around the spot where the skewer is. That is, unless you put the skewer in the air; then it will leak.

More ideas for a fun party

When it comes to Halloween, there are always scary ideas around.

—Fake edible blood: Combine light corn syrup with red food dye until you get a shade that resembles real blood. Add a small amount of cocoa powder to the syrup mixture to darken the shake and make it turn opaque, like real blood. Too thick? Thin it with water. Too thin? Thicken it with flour or cornstarch, mixed in slowly. Mmmm. From www.wikihow.com. Science principle: Uh, none. But fun.

—Dry ice vapors: This is only for adults to work with. You need to be careful when handling dry ice, which can frostbite your hands. To find a retailer for dry ice, check online.

To make a steaming caldron of vapor, place the dry ice in a container and add hot water, which will make a foggy vapor arise. This works great outdoors on Halloween night.

If you want the vapor to come out of a pumpkin, carve the jack o’lantern, then place a tall container inside with some dry ice. Add hot water and voila!

For a punch bowl, place a smaller bowl to hold punch inside a larger bowl that will hold the dry ice and water. It will appear that the steam is coming from the punch, but it will be the outer bowl. (You don’t want anyone accidentally sipping on dry ice!)

Science principle: Dry ice is the solid form of carbon dioxide (CO2). As it melts, it bypasses the liquid stage, instantly becoming a gas. When the very cold CO2 gas bubbles move through water and hit the air, some of the water in the air condenses into tiny droplets and forms a fog of air, water and CO2 that is heavier than the surrounding air and stays near the ground until it warms.