Experiences

Gravitation power

Mária Dojčanová

Slovakia

High Secondary School

Physics

Teaching in class

Direct

The lesson objective is to develop logical thinking and acquire skills in the calculation of the gravitational force.
In the initial part of the lesson I repeat the basic concepts with the pupils - gravity, gravitational forces, gravitational field, the general law of gravity.
In the application part of the lesson pupils solve examples to calculate the size of the force of gravity.
Problems I face:
• When calculating the size of the gravitational force sin such a way that the pupils appoint specific numbers to the physical quantities, many have mathematical difficulties in expressing the result, since the gravitational constant is a very small number.
• In the second case, when I try to assign tasks to logical reasoning, for example: How will the value of Fg changes if the mass of the first body increases 3times? - In this case usually respond correctly. In case of: How will the size of Fg changes if the distance is reduced or enlarged by 2-fold? – Here become the difficulties with mathematical expression.
Many students have difficulty with the adjustment fractions, mainly composed of fractions and those with squares.
Although I try to guide students to think logically when speaking about what happens to the force of gravity if you zoom (reduce) the weight, increase (reduce) the distance in mathematical terms, many have no problem to write an incorrect result resulting from a mathematical error they made. A student often does not logically verify the result.
Another problem which I encounter in physics is the expression of an unknown value in the physical relationship.
But these are all problems based on inadequate math skills of the students.