Thursday, November 18, 2010

Here's how I teach variables in science

Here's one way I use to teach students about variables in a scientific experiment.

Because I believe in teaching students with projects or problems that are in-a-context and for a purpose, I needed to come up with something other than worksheets or direct instruction for teaching kids about responding, controlled and manipulated variables.

So, I wrote this fictitious research report and had the kids read and think about it:

Teachers' Institute of Action Research
After a yearlong study of students, it is our recommendation that grade 6 students be assigned 3 hours of homework per night with an additional 5 hours of homework on the weekends. 
Details of our Study
Our conclusion is based on an experiment conducted on students from Red Deer, Alberta. These students were split up into two groups. One group consisted of twenty grade 6 students while the other group consisted of twenty grade 12 students. 
For one year, each grade 12 student was assigned 3 hours of homework every night and 5 hours of homework on the weekend while the grade 6 students were assigned no homework. At the end of the year, both groups were given the same test based on math, social studies, science and language arts. 
The grade 12 students scored very high on the test, but the grade 6 students scored very low. 
Our research clearly shows that homework is necessary to make students smart.

Before I print this report, I modify the margins and double space the text to give students more space to show their thinking. Here's what it looks like:

Teachers' Institute of Action Research

For more on how I encourage them to show their thinking, check out this post. Basically, I have them record their thinking in the margin while they read. I encourage them to ask questions, make metaphors, share comments, express feelings, record memories and draw diagrams. 

During our class discussion, I had the kids share their feelings on the report. Everyone was critical of the study, but for different reasons. Some were emotional about it and thought evenings and weekends were better used for family time, sports or other personal interests - while others used logic to criticize the experiment's lack of fairness. 

For example, Terry thought that the experiment should be redone but this time only comparing grade 6 students to other grade 6 students. But even then, he wondered how the kids would be chosen - one group might be more intelligent and greater skilled than the other simply by accident. 

Jake questioned the experiment by wanting to know the difficulty level of the final test. As a class, we agreed that the report really didn't specify this - even though it would be important to know such information. I was pleased to see the kids reasoning that it is in fact their right to demand more information than the report offered.

When I asked the kids for the responding variable in this homework experiment, Lilly thought it was the report's last sentence "Our research clearly shows that homework is necessary to make students smart." This led to an interesting conversation about the difference between the responding variable and the conclusions drawn from the results. The kids had a hard time differentiating between the these two ideas.

The next project is for them to write up a fictitious study, as I did, and find creative ways to make the study fair or unfair. Then we will read each other's studies to see if we can identify how the variables may or may not have been designed appropriately.


  1. I like this idea. I feel like your description of your idea could use a bit more explanation on the connection between the idea of variables and what's being measured in the research study. Is the number of students a variable? What about the IQ of the students? Obviously we can reason this out, but just a one line description of how the kids recognized the variables from the study explicitly would be useful. Obviously they've understood the concept from the discussion of whether or not this study is "fair".

    Some people might think that choosing a "controversial" topic might not be appropriate for the classroom, but in my opinion, controversy is where some of the best learning happens. You haven't crossed any inappropriateness lines, you've just made the kids think. Kudos there.

    Isn't it weird that the effects of homework on students is considered a controversial subject? It's like we aren't even "allowed" to bring it up without sounding like a radical in some circles.

  2. Joe, how will you give them the opportunity to use alternate ways to express their fictitious study? What I mean is, will it be text-based as your report is or do they have the ability to create and peform/record, say, a role-play with a partner or group to show a simulated exercise that summarizes their fictitious study?



  3. I just stumbled across this as I am preparing for my first year of teaching. I'm teaching 5th grade science in Mountain Brook, AL and we're learning variables during the first few weeks of school. I really LOVE this idea and I am going to create my own rendition of it. Thank you so much for sharing. I'd love for you to come check out my blog! I plan on revisiting yours frequently.


Follow by Email