Teaching balancing equations to high school students is difficult, because often some of the students are still at Piaget’s concrete rather than abstract reasoning stage. That is, they can’t just see the molecules in their head and/or draw them correctly. This lesson plan makes use of Chembalancer, an online app, which makes that abstraction concrete – all of my grade 9 class mastered balancing equations in an hour (including the remedial students) using an early prototype of this app.
Directions:
1. Go to http://www.dun.org/sulan/chembalancer and check it out.
2. Go to http://www.dun.org/sulan/chembalancer/worksheet.htm. Print out a copy and photocopy as needed for your class.
3. Go down to the computer lab, hand out the worksheet, and have the students play the Chembalancer game at http://www.dun.org/sulan/chembalancer (or just double-click the default.htm page if you had to had to download and install local copies from chembal.ZIP as described at the bottom of http://www.dun.org/sulan/chembalancer)
4. If you want, you can get the students to show you the final.htm page when they finish (instead of you having to mark #1-#11 on the worksheet), then initial their worksheet to say they completed the game.
5. Get the students to do #12 and #13 on the back of the worksheet.
Next class, if needed, hand out the traditional paper and pencil equation worksheets, and let them balance the equations without using the computer, to reinforce the concept and for practice.
Here is the answer key for the problems on the worksheet:
1) 1, 1, 1
2) 1, 1, 2
3) 2, 1, 2
4) 1, 2, 2
5) 2, 2, 1
6) 1, 2, 1, 1
7) 1, 2, 1, 2
8) 1, 1, 1, 1
9) 1, 3, 2
10) 4, 3, 2
11) 4, 2, 4, 5
12) 2, 2, 2, 1
13) 1, 2, 1, 2
Questions? Comments??
sulan@dun.org