Today I begin by asking students to read the I Can statement with me. We read, "I can follow an experimental design to complete an experiment." I ask students, 'What do you think it means by experimental design?" I let them give their ideas about what an experimental design is. I reinforce correct responses and shape those that may be close. We come to consensus that an experimental design is a set of directions for conducting an experiment.
I say, "Today I am going to give you the experimental design. I want you to follow the directions to set up the experiment. What do you think goes into the design?" Here I want students to begin to verbalize the parts of an experiment - a question, hypothesis, materials, method, results and conclusion. My goal is for students to show their understanding of an experimental design, and to be able to use the scientific terms correctly.
For this experiment, I have written the experimental design out for students. celery experiment.pdf I partner students up using their Buddy Wheel numbers. I give each team a direction sheet. I say, "I want you to begin by reading the entire sheet to each other. You may read it together (choral read), or you may take turns reading a section. As you read and finish a section you must both initial it showing that you read or listened to the directions. Before putting your initials on the paper, talk to your partner if you are not sure about what something means. I will give you 5 minutes to read and initial the form. If you finish earlier, talk to your partner about what you think is going to happen, and about what you will be doing." I ask questions and for 1 student to repeat the directions so I am sure that everyone understands what to do.
After about 5 minutes, or when most groups are done, I ring the bell and say, "does anyone have any questions about what you will be doing to set up this experiment?"
I say, "Now you and your partner will follow the directions. Your materials are here on the front table. You will initial each step as you complete it. You will not be able to fill in results and conclusions right now. Why is that?" (The directions say to leave the experiment for 3 - 4 hours but we found that overnight was better). "Right, so right now you will only be setting up the experiment."
I check for understanding and then allow students to take the directions, gather the materials and set up the experiment. I assist groups who may be having trouble reading and following the directions.
When each group has the experiment set up, we set them aside until the end of the day when we will add our results and conclusions.
At the end of the day, I ring the bell and invite students to come to the rug. I say, "This morning you set up an experiment with celery and colored water. I would like you to look at your own cup, see if anything has happened and record your observations and conclusions, the answer to the question based on what you discovered, on your journal page. I will give you 10 minutes to do this."
I want students to draw their own conclusions based on evidence. This is a skill that students should begin to develop. I circulate around the room to check on student understanding and to ask them to justify their conclusions based on what they see with their plant.
After 10 minutes I invite students to place their cups back on the table and to return to the rug. I ask for students to share what they discovered and to tell us how they decided upon their conclusions. I use a talking stick and pass it around the circle so that everyone has a chance to listen to each other's conclusions. I want to encourage students to engage in scientific discussion as they draw conclusions based on evidence. Sharing The Blue Celery Explaining the Results
I take notes on student ability to express their conclusion and justify it based on evidence for ongoing assessment.