WHAT'S A CRYSTAL FOR?

When I was teaching hands-on science, we also gave "prompts" to our students to write and practice their science research projects and write ups. After the writing was over, science teachers from all over the city, gathered together to score the students with predetermined rubric. I will never forget one student's research. The scientific method was impeccable as well as the method to record the results. Even the conclusion was well researched and written to argue her point. The only thing is that further research or even different wording of the prompt may have lead her to an altogether different method and conclusion.

This was the prompt: You are given 20 tomato plants and the garden area in which to grow the plants and water. Plan an experiment to see if adding crystals actually do help the plants grow faster or slower. Draw a graph and a diagram to show how you think the plants will grow.

Now, my students were urban children with very little "gardening" knowledge except for the bean they watched sprout in their paper cup and the plants I had growing around the room. So this student used that knowledge to design an experiment to watch the effect of crystals on growing tomatoes. The hypothesis was: "I think the crystals will help the tomato plants to grow twice as quickly than the tomato plants without the crystals because the sunlight will be intensified by the crystals, giving the plants more energy with which to grow." Curious!!???

I went on to read the process of the experiment only to find out that the student had cleverly incorporated her knowledge of light and refraction of crystals from rocks with, apparently, prismatic crystals she had seen and used around her home. She decided to hang the crystals in the trees above the tomato plants, to aid the plants in photosynthesis and growth. The crystals were large and drawn with the angles that diamonds might have. They were hung at heights appropriate to allow the sunlight to be effective and would obtain the optimum exposure throughout the day. The crystals were hung in trees and fences surrounding the garden. Lines indicated the rays of sunlight being refracted to the tomato plants below. The diagram was artistic as well as accurate. There were tomatoes growing on the plants. Her graphs indicated the projected growth in circumference of the tomatoes as well as height of the plants. She had projected only the rate of growth to amount of sunlight variable as accurately as her knowledge of light would allow. Her control diagram was exactly the same sans the hanging crystals.

However, there was one problem. The crystals, that were implied for use in the experiment, were grow crystals such that you would find in the popular "Miracle Grow" plant fertilizer. The writer of the prompt had chose the word "crystals" without any further adjectives or explanation for what the crystals looked like or how to use them. These students had no knowledge or experience in using "crystals" to enhance the growth of vegetables, flowers and plants. Perhaps it was my fault for not emphasizing that nutrients are found or can be added to most soils and might contain nutrients in the form of crystals..

Her experiment plan created a conundrum among the teachers who scored her prompt. The hypothesis could be tested. One variable was being considered at a time. The steps to the experiment were solid. Her resources and sources correctly sited. Graphs and diagrams were detailed and neatly drawn. Even her handwriting was clear and legible.

At last, we concluded, the student had met the criteria set up in the scoring rubric. Nine out of the ten scorers gave the student a top ten. The prompt has since been re-written, and I now include the use of fertilizer and nutrients when potting our beans. This is just one example of how cultural experience can effect students' test performance.

In the same group of science writing prompts, the students were asked to create an experiment comparing the number and size of the peanuts inside of the peanut shells. This would also demonstrate their ability to observe and measure. If only.....half of our student population had not been allergic to nuts or peanuts, this may have been a pretty good prompt. As it was, even the non-allergic students could not open the peanuts, nor could the teachers allow them into the classroom for fear of an allergic fatality. I can just hear the writer of that prompt smacking their head and repeating the proverbial Simpson exclamation, "DOH!"