Minority Scientists' Showcase

Magic introduces kids to science principles

Kids visiting the Minority Scientists' Showcase last month got a chance to pick up some good magic tricks that they could do at home.

The St. Louis Science Center holds the annual Showcase to give minority kids and their families a chance to see some of the science careers available at local companies.

This year's 16th annual Showcase was held Saturday, Sunday and Monday, over the Martin Luther King holiday weekend, Jan. 19-21.

Many of the Showcase exhibitors had staff members to explain scientific processes used to make the group's products. But, many booth demonstrations also showed simple scientific experiments that make good home magic tricks.

The Science Center also had a group of its YES students on hand to show other magic tricks to visiting kids.

Adrian Lindsey is a sophomore at Parkway North High School and a volunteer member of the Science Center's YES Corps. That stands for Youth Exploring Science. The feature of Adrian's booth was a demonstration of "anti-gravity coins."

Everyone knows that if you let go of a coin it'll fall to the floor. Adrian showed kids that wasn't always the case.

The trick was to take a small paper cup and attach a string through the bottom of the cup, using a paper clip. Then, you put a coin inside the cup. But, instead of dropping the cup, you swing it around in a circle over your head.

The coin doesn't fall because the centrifugal force of the spinning keeps the coin stuck to the bottom of the cup, even when it was upside down.

Another YES booth invited kids to compete in a "soda can race." You made the cans move without touching them. You used a filled balloon that has been given a negative of static electricity by rubbing it with a soft cloth.

As the balloon got close to the can, the balloon's negative charge attracts the metal can, which has a positive charge. Therefore, the contestants could pull their cans toward the finish line without touching them.

Sigma-Aldrich Corp. had a whole pamphlet available that gave directions on how to do a number of different magic tricks using science. The pamphlet was titled, "What does a Scientist do?"

One of the simple experiments that kids could do at home involved making "silly putty." In addition, the company had some jars of "silly putty" made up that kids could take home to use.

The "silly putty" formula includes a cup of white glue, such as Elmer's; a cup of liquid laundry starch and a plastic container. You put the glue in a plastic container and slowly stir in the liquid starch.

You continue to stir in the starch until the mixture gets smooth and rubbery. Presto, you have "silly putty" that you can shape into a ball that bounces and stretches.

Another experiment listed by Sigma-Aldrich was how to clean pennies and other coins with a mixture of 3 tablespoons of white vinegar, 1 tablespoon of salt with some water. That mixture becomes a diluted hydrochloric acid.

The pennies become dull when oxygen in the air combines with copper to make copper oxide. The hydrochloric acid cleans off the copper oxide and fresh copper shines through.

The pamphlet also explains how fireflies give off light. The light is caused by an enzyme in the flies' belly is exposed to the oxygen in air to give off a bluish light. This light is different in another way; the light doesn't have any heat attached to it, like light from an electric bulb.

So, the fireflies' light is "cool" in two ways, both "cool" as "wow" and "cool" as in non-heat "cool."

(Another feature of the Sigma-Aldrich handout was a grid puzzle that helps kids expand their scientific vocabulary. See below.)

Monsanto's booth had an experiment where kids could test the pH of red cabbage juice.

Rawlings Sporting Goods had some neat samples to show how both wooden and aluminum bats are made. Also, the booth had cutouts of baseballs, showing how both major league and kids baseballs are made.

The company has a technical development facility in O'Fallon, Mo. The firm has the exclusive contract to make all the baseballs used in major league games.

Although most kids' baseball teams use aluminum bats, the City of New York has banned metal bats because of concern the bats make the balls go too fast and can cause injuries. The Showcase booth also had a sample of how a wooden bat is made from a piece of ash wood.

Another controversy in baseball is whether lighter, drier air in major league parks at higher altitudes such as in Denver, cause the balls to fly further. The Rockies keep all balls in a humidor that keeps the temperature at 72 degrees F and humidity at 50%.

Asked whether that changes the balls flight, the attendant said, "I can't answer that."