The black cherry Kool-Aid and the lemon lime Kool-Aid absorbed and reflected light in different ways. A mixture of the two, analyzed by a spectrophotometer, revealed characteristics of both flavors to science students at Community Christian School this week.
Dr. Bruce Jacobson, a St. Cloud State University science professor, led students through the exercise Wednesday in the Science Express mobile science lab. People driving down 19th Avenue in Willmar this week have probably noticed the semi trailer parked outside the school.
Middle school and high school students from CCS have been running from their building to the trailer all week for science class.
"I don't know if you realize how much you learned in the last 35 minutes," Jacobson said to a middle school class.
He had started the lesson talking about the spectrum of light and describing how different-colored objects absorbed and reflected different parts of the spectrum.
Using spectrophotometers, students graphed the colors reflected by five known Kool-Aid samples and then an unknown mixture which was about the color of weak iced tea.
The peaks of the unknown graph matched the peaks of the two colors in the mixture.
Jacobson then explained what characteristic properties are. For example, gold is known to be shiny, and that's one of its characteristic properties, he said.
The way in which each Kool-Aid dye reflects and absorbs light is also a characteristic property, he added.
By graphing the known colors, the students were able to figure out which colors were in the unknown mixture by comparing characteristic properties.
Becca Mulder and Jordan Starkenburg, both sixth-graders, were a little surprised at some of the graphs they saw. For instance, with the grape Kool-Aid, "they don't have just red and blue in them," Jordan said.
Becca said they had expected to see steeper graphs, but instead saw gentler slopes that indicated the dyes reflected more different colors than they would have thought.
CCS science teacher Sam Greene circulated around the six-station science lab, offering suggestions and checking to see if each group of students was getting similar results.
Greene attended training sessions in the lab last summer along with other teachers from around the state.
The teachers got a taste of the lab's possibilities and earned a chance to have the lab spend a week at their schools in its pilot year of operation.
"This gives us an experience with materials that our school does just not have at this point in time," Greene said.
Greene hopes the school will someday have some of the equipment students got a chance to use this week. Some of it should someday be within reach of the CCS budget, he said.
Jacobson has said that some of the equipment in the laboratory is too expensive for any public schools and most private schools in the state.
Jacobson said the 53-foot semi trailer has had a successful first year. It has had a full schedule visiting private and public schools around the state during the school year. Next week it will be at Central Minnesota Christian School, and it is scheduled to stop at Willmar Senior High in mid-April.
With the lab's two large slide-out sections extended, it offers a 16-by-22 lab with six fully equipped stations and a conference room. It can accommodate up to 30 students.
The Science Express is the state's first mobile science lab, and so far it is proving to be quite popular, Jacobson said. He filled the first year's schedule and had to turn some schools away.
Similar labs have been used for some time in other states. In Connecticut, there's a four-year waiting list for the mobile lab, Jacobson said.
Jacobson has worked on developing the lab for some time. His first plans were simple, a used semi trailer that could be fixed up a bit. Then Medtronic donated a trailer that had been used for physician training. Grants from the Minnesota State Colleges and Universities Bioscience Initiative helped equip the lab.