Experiences

Stereometry for 3. class

Zuzana Zuštinová

Slovakia

High Secondary School

Maths

Teaching in class

Direct

There is 31 students in the class. Mathematics is taught one class per week but given that one week the students go to school and one week is the practical training we meet twice every other week, which is a very little frequency. Level of knowledge in this class is low. Therefore I eased demands on them in order to achieve at least mediocre results. In class, I showed slowly a presentation, where I reiterated surface and volume solids - cube, cuboid, prism, cylinder, pyramid and cone.
I explained and showed students how to draw a body in free parallel projection. I reminded students of the formula to calculate the volume and surface of the bodies. In the presentation they could have seen the network's elements. We calculated a few examples together.
I wanted to rehearse the taught matters so I gave away models of cube, cuboid and cylinder to the pairs of students. I asked them to measure the size, draw the body into their workbooks and calculate the surface and volume of each solid. Not even one student was able to solve the task. They did not know how to measure the dimensions and draw a body, let alone choose a formula and calculate the job. Since I saw the problem, I presented the slide show again. Everything was repeated again. Nobody did the right calculation or was just drawing rectangles.
During the next class, I asked a pair of students to come to the blackboard and gave them a block ruler to measure the dimensions and mutually control each other. Others should just watch and pay attention. One student outlined a body on the board with minor errors and wrote down the dimensions. The second pair had to do the same with a cube, the third pair received a cylinder. All six were grated. Then all the students were supposed to choose formulas from the mathematical tables and using the calculators calculate the volume and surface area of these three bodies. All students gradually presented me the results of these tasks that I evaluated. Despite my warning to be cautious students did not draw pictures correctly. Some did not mark the dimensions, the finished level of some students was inadequate and calculations inaccurate. For the cylinder capacity they used dimensions in the formula for the radius and the average, they did not understand that it is just one formula. They took down partial results in their workbooks and rounded them, although I still explain that they have to calculate everything on the calculators and round off only the final result.
I am not satisfied with the outcome of this class, even though my rating was mild. The worst mark was C. At the end of the class one of the students showed me the old calculations with other dimensions meaning he did nothing the whole class and therefore failed in the grading.