This lesson is appropriate for any teacher who is developing Practice 3: Planning and Carrying Out Investigations and Practice 1 Asking Questions and Defining Problems.
I start the lesson by having students visit the MysteryNet Kids Mysteries Site and attempt to solve the "Case of the Ruined Roses". Students are immediately drawn in, wanting to solve the mystery after reading the scenarios and clues. It only takes a few minutes, as it is a pretty quick read.After giving them a few minutes to work through the mystery, I explain that the process of conducting a science experiment is very similar, if not exactly the same, as solving a crime. Scientists, like detectives, must collect data (or clues) to come up with a hypothesis as to how something works (or who committed the crime). I tell the students that by reading and using the clues to try to solve the mystery, they just formed a hypothesis, or educated guess, in order to explain a phenomenon. Today, we will talk about how scientists hypothesize what makes a good hypothesis.
We read the information on the top half of the Writing Your Hypothesis page. While reading, I direct the students to highlight important information, modeling if necessary*, under the document camera. You can also view my screencast to learn how I use technology to help my students learn to highlight.
Next, I direct the students to the five statements on the bottom of the front page. I have the students work with their nose partner to read through each sentence and identify the dependent and independent variable in each.
Upon finishing, I call on random students to identify each variable. I ask students to raise their hand if they agree with their classmate. For those that don't raise their hand, I ask them why they disagree. This strategy has two major purposes. First, it mandates active participation and holds students accountable for participating in the activity. Second, it allows students with differing viewpoints to justify their reasoning and opens up a discussion about the content and students' thinking. There are times when I also randomly call on students who do raise their hand to explain why they agree with their classmate. Again, this mandates participation and requires every student to be prepared to justify their thinking.
*See reflection, "Teaching Students to Highlight"
Next, we read through the tips on the top of the next page, highlighting important information that students think they should remember as they form their own hypothesis.
I explain to the students that I would like to conduct my own investigation in class, not only to help them learn about how to create a science fair project, but also because I think it would be interesting. Since we are in the middle of cold and flu season, I am interested in investigating how many germs are truly passed onto our food if we do not wash or sanitize our hands before eating. I explain that this might be helpful information to know, since many kids have recently gotten sick and I want to do all I can in class to keep everyone healthy. Since the students had crafted their own questions in yesterday's lesson, I decide to post this idea to them and and ask them to help me in crafting a scientific question that would address the idea I would like to experiment. I remind them of the four sets of criterion we discussed yesterday, and ask them to brainstorm a possible question or two that I could use as a map to help guide my investigation.
As students begin to think, I rewrite our criterion from the prior lesson on the board as a student reference. I ask students to share ideas with their table and come up with one solid, testable question, as well as one well written hypothesis statement, that we could use to guide this investigation as a class. I give the students 1-2 minutes to discuss their ideas, then call on one students from each group to share the groups' thinking. I copy each one on the board, and evaluate each one using a Think-Aloud strategy so the students can hear my "thinking".
After providing a little gentle guidance through my think-aloud, I ask students to vote on a question and a hypothesis. This provides students with the opportunity to take ownership of the class investigation, even though I have chosen the topic and guided the direction of the discussion.
I erase all of the other possible questions and hypotheses, and copy ours in a Google Doc that we can refer to later when we begin the process of conducting our experiment.
Now that students have a handle on how to properly form and write their hypothesis, I have them read through the hypotheses on the back of the page, and evaluate each to determine if they are written correctly. After all of the students have had the time to evaluate each statement, we review them as a class, following the same procedures I did in the last activity.
Finally, I return the students' index cards from the prior lesson and direct the students to refer to their own science fair question. I have them craft a hypothesis statement, related to the question, on the back of their card that explains what they expect to happen once they perform their experiment. After they write, they share their hypothesis statement with their table mates, and provide feedback based on what we have learned throughout the lesson.
Once the students have written their hypothesis on the back of their index card, I collect the cards and read them one by one. If their hypothesis statement meets all of the criteria we have discussed, I will approve it and have the students type both the question and their hypothesis into a Google Doc and share it with me. We use this document for all other portions of the project from this point on.
If it is not approved, I meet with the student one-on-one during or after class to elicit more information or explanation or to help them to revise their hypothesis before creating their Google Doc. Knowing who has struggled with this step helps me to determine who may need additional support with latter parts of the project.