For those of you who are unfamiliar with the Tomatosphere Project I encourage you to view their comprehensive website. Briefly, schools can enrol to be part of a blind test. They are sent two sets of genetically identical seeds – one of the sets has been exposed to a simulated space environment at the University of Guelph, the other set has not. Students are asked to plant the two sets of seeds and track their germination rates. This data must be submitted online before the teacher is informed of which set of seeds was exposed to microgravity and which was not.
I like to start this experiment while we are studying the grade nine space unit. It leads to many questions, such as:
“What is microgravity?”
“How do seeds germinate?”
“Are tomatoes fruits or vegetables?”
“Why would they want to grow plants in microgravity?”
“What will people eat when we colonize Mars?”
All of these questions, and many more, come from the students and each one leads to a teachable moment.
The design of the Tomatosphere Project predetermines the dependent and independent variable for the students. Yet they still need to identify them. In addition, they determine what the control variables for the experiment are and decide on their values.
After distributing the Smarter Science starburst graphic to the students and describing the Tomatosphere Project to them the students were able to define “what would be observed” as the germination rate, as prescribed by the project. Therefore they wrote “germination rate” in the centre of the star burst as their independent variable. The dependent variable, which they filled in at the bottom of the page, was if the seeds had been exposed to microgravity, or not.
Together we brainstormed the control variables, each of which were written around the rays of the star burst. The list was:
• Size of pot
• Amount of soil
• Type of soil
• Location pot kept in
• Number of seeds
• Depth at which seeds are planted
Each student decided the value to give each of these variables then set up their experiment. This also led to a teachable moment on the important of labelling! Fortunately, I have a greenhouse attached to my classroom which allowed them all to choose their own spot in the greenhouse to place their two pots.
Once the seeds were planted the students then had to design their own observation tables. This was the most difficult task of the day. They really struggled with it. I kept telling them to make columns for whatever they were going to observe every day. Overall, this task was poorly done on the first day yet I managed to resist the urge to dictate the table headings to them.
The second day when the students came to class and checked their plants they were disappointed that no tomatoes had sprung up overnight. Nevertheless, I insisted that they still had to write down what they saw and what they did (if anything) to each pot. Now they could identify what was wrong with their observation tables. They asked me things like: “Where do I record how much water I gave them?” Eureka! Now I could tell them to add a column to their table! There were several aha! moments in class that day as the students realized what was wrong with their observation tables. Some even choose to redesign theirs from scratch.
For now we are watching, watering, recording and waiting. What will the two sets of tomato seeds do this year? I don’t know. It’s a blind test! But I will blog about it later when are results are in. In the meantime, I urge you to get involved!
For many of the students in my classroom it is the first time they have ever watched a seed germinate, thereby allowing me to provide them with some prior knowledge before we start our ecology unit. The students become very emotionally attached to their plants. They name them, they rush in to see them before class starts, they worry about them over the weekend, and they take them home and transplant them into their own gardens at the end of the experiment. There is a lot of friendly completion as they compare their plants to the others and a great deal of pride in the finished product. As the plants grow the students become more attuned to the importance of keeping everything equal between the two sets of plants and the importance of a controlled experiment becomes self-evident to each of them.
What types of seeds have you had success with in your classroom? Send me a tweet @EurekaTeacher