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Quick and Simple Science Fun

Sink or swim

What you'll need:
* corn syrup
* green and blue food coloring
* vegetable oil
* a paper clip
* a grape
* a plastic bottle top

* Pour one inch of corn syrup into a tall glass or jar and stir in a drop of green food coloring.

* Have your child mix a drop of blue food coloring into a cup of water. Let him carefully pour the water on top of the syrup.

* Add one inch of vegetable oil on top of the water.

* Once the liquids have formed distinct layers, have him drop into the jar a paper clip, then a grape, then a small plastic bottle top.

* Watch how the objects slowly fall and eventually settle on different layers.

How it works: Corn syrup, water, and oil are all made up of tiny particles called molecules. The more tightly packed the molecules, the more dense --or heavy --the liquid. Here, the syrup is the heaviest liquid, followed by the water, and then the vegetable oil, which explains why the syrup sits on the bottom of the jar, the water is in the middle, and the oil rests on top. The same holds true for the objects dropped into the jar: The paper clip is most dense, so it falls to the bottom. A grape is less dense, so it sits in the middle of the jar, at the bottom of the water. The bottle top is the least heavy, so it floats on top, in the oil.

Getting fizzical

What you'll need:
* a zipper-lock sandwich bag
* vinegar
* liquid soap
* glitter (optional)
* baking soda

* Fill a zipper-lock sandwich bag with a half cup of vinegar and a tablespoon of liquid soap (and a pinch of glitter, if you have it).

* Take it outside and add a tablespoon of baking soda.

* Seal the bag, shake it once, hard, then set it down on a sidewalk or driveway (you may not want to put it on the lawn since it can leave a small burn mark).

* Stand back! Within three or four seconds, the bag will quickly fill with bubbles, then burst, sending suds flying out.

How it works: When the baking soda comes into contact with the vinegar, a chemical reaction occurs, and a bubbly gas called carbon dioxide (the same fizzy substance found in soda) is created as a result. The gas fills up the bag, causing it to expand and explode.

Magic milk

What you'll need:
* milk
* a pan
* yellow and green food coloring
* a toothpick
* liquid soap

* Pour a cup of milk into a shallow pan and let it warm to room temperature.

* Let your child add a few drops of yellow food coloring to one side of the pan and a few drops of green food coloring to the other.

* Have her dip a toothpick into liquid soap, then dunk it into the center of the milk.

* Watch the colors make wacky swirls as they dart away from the toothpick toward the edges of the pan.

How it works: Both the milk and the soap have what's called surface tension --a stretchy, invisible "skin" that holds the liquids in place. The soap's surface tension is weaker than the milk's surface tension. So when the soap touches the milk, the milk --with the food coloring in it --goes racing toward the parts of the pan with stronger surface tension.

An egg-cellent trick

What you'll need:
* an egg
* matches
* a glass bottle

* Hard-boil and peel an egg; set aside.

* Drop two lit matches inside a glass bottle with a long, narrow neck and an opening just wide enough to keep the egg from falling in (we used a milk bottle).

* Have your child set the egg on top of the bottle's mouth while the matches are still lit.

* Watch the egg get sucked down into the container.

How it works: After the matches burn out, the air inside the bottle cools, lowering the pressure there. Now, the air pressure outside the bottle is greater, pushing the egg inside.

Static power

What you'll need:
* tissue paper
* a balloon

* Have your child cut a wavy snake out of tissue paper, then fold its head back so it lies flat against the rest of the body.

* Set the cutout on a wooden or tile floor.

* Rub an inflated latex balloon on felt, a wool scarf, or your child's hair.

* Have him hold the balloon just over the snake so it jumps onto the balloon.

How it works: Static electricity is created when atoms release energy in the form of electrons (negative charges). When certain things are rubbed together, like balloons and hair, their electrons move from atom to atom. This makes those items electrically charged. Once the balloon is charged, it will attract things that don't have a charge, like the paper snake.

Contributing editor Barbara Rowley, a mom of two, lives in Big Sky, Montana.

Our science experts: Rick Sanborn, former director of Sanborn Western Camps, in Florissant, Colorado; Brian Jones, director of the Little Shop of Physics at Colorado State University; and Pat Murphy, author of family science books from the Exploratorium Museum in San Francisco.

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