Category Archives: hands on

"Balancing" Equations

Here is a lesson that I taught a couple of weeks ago. I wanted to cement in the students minds that you must treat both sides of an equation the same to keep them equal or balanced. I always tell a story about “being fair” that whatever you do to one side of the equation you must do to the other side or it will get angry with you and give you the wrong answer. I should mention that this is a 6th grade math class and their first exposure to equations.

I made up a dozen of these scales with scrap wood from my shed over spring break and used pennies as weights. To calibrate them I had the students put paper clips in one side until they balanced (somewhat evenly).  I then used some items that I had multiple copies of laying around as the variables. The problems are a bit contrived but I was trying to show more than just addition in the equations.

One problem is that not all of my items were exactly equal to a certain number of pennies. For example the marble is closer to 2 1/2 pennies instead of exactly two pennies. I could tell my students were too used to “book problems” where every answer comes out neatly because they were easily sidetracked by the calibrating and the fact that the answers did not balance perfectly.

I used this as my first lesson and they did not all “get” it the first day. Some of my more abstract thinkers quickly found it easier to just “do the math” without the scales. What I thought was successful was that for the rest of the unit I had a mental image to refer back to to remind students that equations must balance.

Lego Robot Erase

My students, Cullen, Jordan, and Jordan designed, built the robot, and implemented this program where the robot follows a black line and then erases it.

Pneumatic-Powered Truck

My 7th grade technology class always designs a pneumatic-powered device. We use syringes and tubing as the power source. Anthony made the best one ever: a dump truck with doors that open and hydraulics. I then made my first youtube video to document.

I love projects that let kids be creative!

Paper Platforms

I usually write about the new things that I am trying in my classes, but I realized this week that some of my “old” lessons are worth sharing. In my 6th grade technology class I have always taught the paper platform lesson. The source of this comes from my mentor technology teachers Larson and Roode, a true master of teaching kids to come up with creative solutions.

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The paper platform project challenges students to build a three inch tall platform that can hold as many pennies as possible. The beauty of the challenge is that it is cheap and simple, yet not easy. I do not give students hints or help but ask lots of questions about their practice models. I often see all A students frustrated by this project because I will not help them solve it. I also feel it validates some students hands on skills that are often undervalued in school, but are important in the real world.

I have had lots of very different solutions over the years. The current world record is over 1500 pennies and the students get their names posted on my “Wall of Fame.” What lesson do you use to teach problem solving?