Background

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One of the difficulties in electrical studies faced by secondary school students is determining the arrangement of loads in an electrical circuit, whether they in series or in parallel arrangement. This is due to the misconception of the terms “parallel”, “series” and the comprehension of the term “potential difference”.

Often teachers are inclined to introduce the parallel and series arrangement of loads in a simple geometrical form (Refer 6-D1 and 6-D2).

As a result, when students are given a much complex circuit (Refer 6-D3 and 6-D4), the students are baffled by the arrangement.

Objectives

Hence the purpose of this entry are :

• To introduce Grace Method in rearranging complex circuits to a simpler form

• To give example to clarify the alternative conception of most students that parallel circuits are just circuits arranged in a simple geometrical form.

Benefits for teaching and learning process

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Grace Method, a concept originated by the author, was developed in such a way to help students to rearrange complex circuits to simpler circuits which are much familiar to them and thus, clear the alternative conception they may have before. After implementing Grace Method the results were remarkable. Students were able to solve the questions at ease. Besides that,

• Students have a better degree of understanding about potential difference.

• Students have a better grasp at using voltmeters to measure the potential
  difference in a circuit.

• Students are not nervous when trying to solve questions which involve complex circuits, and as a result, they have better grades in the  chapter on “Electricity”.

• Students were keen on trying out new methods on the arrangement of circuits.

Use of apparatus/ materials and construction of teaching aids

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Preparations of diagrams illustrating various types of circuits.

Implementation of the teaching

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In the middle year of 2003, Grace Method was been introduced to teachers in Sung Siew Secondary School. After teaching students the basic arrangement of circuits, the Form 5 Science and Form 6 Science students tried to solve the more complex circuit arrangements as shown in diagrams (Refer 6-D3) and (Refer 6-D4). They were initially unable to solve these questions. In the next lesson, the concept of potential difference was explained again and the Grace Method was taught to students.

Grace Method and its application

Grace Method

“Points which are not separated by any load are considered to be the same point”

Refer 6-D5, let us denote the resistors as R_1,R _{2 ,}R_3, R_4, R₅ and R₆  and the points as P_1, P_2, P_3,  P₄ and P₅ .

Applying Grace Method, we’ll have

                                                    P₁ = P₂ = P_α

                                                    P₃ = P₄ = P_β

                                                                             and

                                                    P₅ = P_γ

Let us rearrange the circuits in a much simpler form.

1.  R₁  is connected to P_1. As P₁ = P_α, we have the diagram (Refer 6-D6).

2. R₂  is connected to P_1. whereas R₃ and R₄ are connected to P₂ respectively. As P₁ = P₂ = P_{α ,} we have the diagram (Refer 6-D7).

3. R₂ and R₃ are connected to P_3, whereas R₄ is connected to P₄ respectively. As P₃ = P₄ =P_β, we have the diagram (Refer 6-D8).

4.  R₅ and R₆  are connected to P₄  and P₃  respectively. Again, applying Grace method, we have (Refer 6-D9).

5.  R₅ and R₆ are also connected to P_5. Applying Grace Method, P₅ = P_γ, we have the diagram (Refer 6-D10).

At this level, students will be able to recognize the different arrangement in this circuit as compared to the previous one.

Suggestion for modification

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