These units contains activities, majority of which is aimed at students´ independent investigation. They were selected and designed with regard to their potential towards IBSE with strong emphasize on the students´ inquiry.
The activities do not cover all the range of topics concerning direct electric circuit. The goal of this unit is instead to provide inquiry-based activities to support teaching and learning the topic of Direct electric circuit in an inquiry way. As a result there are some concepts that are not the central part of any activity but they are used within the activities (like power, energy delivered to the circuit, electromotive force). These concepts are supposed to be introduced within theoretical lesson before the activity starts.
Electricity is one of the basic areas of physics that are very important at all levels of physics teaching. At the primary level young children gain experience with simple electric circuits. At the secondary level electricity is taught more systematically. In this sense the activities can be used at different levels. For lower secondary level students (aged 12-15), depending on the national curriculum, it is recommended to carry out activities 1, 2, 3, 4, 5.1, 5.2, 8, and 10.
Electricity is one of the most difficult concepts for students to grasp. It is around us but at the same time it is invisible. Current and voltage are difficult to understand because they cannot be observed directly. As a result, there are many misconceptions concerning electricity identified by physics education research .
The most common misconceptions concerning electric circuits involve:
- Current is used up in a bulb. It is consumed while running through the resistor so that less current is flowing back to the battery.
- There is no potential difference across an open switch because V=IR and there is no I.
- Ohm´s Law applies to all circuit elements (not just resistors).
- Electrons move quickly (near the speed of light) through a circuit. That’s why when we connect the bulb to the battery, it lights up immediately.
- Charges slow down as they go through the resistor.
- A conductor has no resistance.
- The resistance of a parallel combination is larger than the largest resistance.
- Battery is a source of electric current. Battery either outputs zero current (if nothing is attached to it) or outputs a standard amount of current, independent of what is attached to the battery. Emf and potential difference are synonymous.
- There is no current between the terminals of a battery.
- Charges that flow in circuit are from battery.
- Current and voltage are the same.
Taking into account the physics education research results on students misconceptions the activities are designed to confront these common misconceptions. To reveal them the teacher should ask questions so that the student can confront his pre-knowledge with the results gained in the experiment. The activity Model of the electric circuit ( why is it more or less resistive) presents an approach to teaching electric circuit concepts described by Herman Haertl that addresses successfully some of the standard students´ misconceptions.
The activities are designed for the certain level of inquiry. But it is up to the teacher and the level of his students to change the activity to more open investigation or vice versa.
Helping Students Learn Physics Better, Preconceptions and Misconceptions, available at http://phys.udallas.edu/C3P/Preconceptions.pdf
Haertl, H.: The electric Circuit as a System: A New Approach, Eur.J.Sci.Educ., 1982, vol.4, No.1, 45-55