By Harold Reutter
harold.reutter@theindependent.com

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A small metal rod can make a big sound as Edgerton Explorit Center staff member Rick Brown (right) leans toward Dodge Elementary students causing them to lean back and Haley Brown, 9, (left) to cover her ears Thursday afternoon during a special visit to the school by Edgerton Explorit Center staff members to teach about water and sound. To help understand water better, Dodge Elementary third-grader Eric Ortiz, 8, squeezes a bottle to create higher fluid pressure during a Cartesian diver experiment. Click Thumbnails to View

Rick Brown took half the school's third-graders to teach about sound, with Ken Schroeder teaching students about water.

Brown started his lesson by asking students to make various kinds of sounds. The first student responded with, "Ummmm " and Brown said that counted.

Students slapped desks, rapped a metal ring on desks, used their noses, whipped their fingers to create a cracking sound and cracked knuckles to make sounds.

Brown used a balloon to make a sound, blowing first against its side, then blowing into the balloon and holding it by the neck to let the air escape in a squealing sound.

He used a spoon to bang on a baking pan and then struck a tuning fork. The common denominator for all sounds were vibrations, a fact that Brown demonstrated by placing the tuning fork in water.

Students placed paint sticks over the ends of their desks and struck them, again causing a vibration and a sound. The longer the stick stuck out from the desk, the lower the sound.

That long-low, short-high principle of sound held true whether the material being vibrated was air, string or metal. He also showed how solid objects can sometimes be better conductors of sounds than "squishy" air.

At one point, Brown put rosin on his fingers and rubbed them along a metal bar, causing the bar to hum and whine, not always pleasantly.

Near the end of the session, Brown had the students make their own version of a washtub bass. Only, instead of a washtub, Brown had students use a plastic cup and string. The string didn't make a loud noise when vibrated, but if students put the cup to their ear, they could hear the sound a little better.

Meanwhile, across the hallway in another classroom, Schroeder was teaching students about water, especially emphasizing that water is sometimes a solid (ice), a liquid or a gas.

Water molecules move very slowly as ice, more freely as water and very rapidly almost like having a party when they exist as a gas.

Schroeder noted that one of the very first engines was the steam engine. He created his own "steam engine" by heating water in a canister hung from a string. The only escape was two bent pipes on opposite ends of the canister. The escaping steam twirled the canister.

Schroeder also heated water in a paint can with holes poked in the lid. Eventually, steam began to escape.

But Schroeder showed that steam wasn't the only thing escaping. He had a student quickly turn the paint can upside down into a tub of cold water.

That immediately caused the steam inside to condense back into water. It also caused the air inside to contract, creating more air pressure on the outside of the can than the inside. The can immediately collapsed, much to the surprise and delight of all the students.

Schroeder also created a Cartesian diver an air bubble in a clear container of water. Increasing the water pressure would cause the bubble to sink, while lessening the water pressure allowed the bubble to rise.