Thursday, March 25, 2010

Surface Area

Teaching Math is truly a challenge. While I like Math, I know that not everyone else does. Especially 6th graders!

Last week we learned how to calculate the Area of squares, rectangles, triangles and circles. We had to learn all of these new FORMULAS !!! (You remember these: A = lw, A = 1/2 bh, A = r2)

Some of the kids got the hang of this right away, others were just trying too hard. I told them that sometimes you have to just accept things on faith, other times you have to look for a deeper meaning.

Just accept these formulas on faith. They are right and they will work.

I managed to get this through to the kids and we moved onto formulas for calculating Surface Area this week.

I started with showing them how you can take a three-dimensional figure and flatten it out into a net. This is one for a square pyramid:
To find the surface area for a square pyramid, you just find the area of all of the flat shapes: one square and 4 triangles.

The formula is based on the formulas for each individual shape, added together.
So the formula for finding the surface area of a square pyramid is: lw + 4(1/2 bh)

Each problem gives the kids the measurements for the length, width, base, and height.

We practice picking the correct formula for each problem (as we learn 3 different shapes and their formulas).

Then we go through the steps to solve this problem.

There is the BIG PROBLEM!

I realize that a lot of the kids do not want to follow the steps, write down what they should be doing, stay organized, pay close attention to what they are doing, or double check their work.

It does not seem to matter how many problems we solve independently, as a group or on the boards. Some will follow the steps and find success. Others will ignore what their classmates and I are doing and continue to try it their own way.

Vince says that the definition of insanity is doing the same thing over and over and expecting a different result.

Yesterday, I had one class talk about tips on how to work these problems and get them right every time. What did they tell their classmates? Follow the steps, check your work, stay organized, use the right formulas.....the same advice I have been giving. I thought that perhaps if it came from their classmates it would have a greater impact.

I was wrong. I still had some of these kids today ignoring everything we spent the past 3 days on.

But we need to move on.

Next hurdle...formulas for Volume.

No comments: