Towards a just, equitable, humane and sustainable society

Learning About the Components and Types of Electric Circuits

0

Duration: 135 minutes (3 periods)

1. Teaching Objective:

To introduce children to fundamentals of electric circuits and make them capable of troubleshooting simple electrical circuits.

2. Learning Outcomes:

Through these activities, the students will be able to:

1. Explain how electric current flows in a circuit and wire a simple circuit
2. Explain the functional difference between series and parallel circuits
3. Represent an electric circuit with symbols

3. Pre-requisites:

At the beginning of this module, students should have the following understanding:

1. Charge is a fundamental property of Matter
2. There are two types of charges
3. Like charges repel and unlike charges attract

4. Materials required:

Assumed class size is 30 and students are grouped in pairs.

• Bulb – 40 no (Each group will use two bulbs; Additional 10 bulbs, 5 switches and 5 batteries are taken in case the components are not working or getting damaged. )
• Insulated copper wire: 1 square mm cross-sectional area and 15 m long (1 m per group of two students).
• 1.5 V Battery – 20 no. (Use dry cell alone having 1.5 V; Precaution:  Do NOT touch the terminals with tongue.)
• Switches – 20 no  (If switches are not available, students can make their own switch with the help of safety pin and thumbtacks)
• Wire Stripper –5 no.

5. Note to the Teacher:

The module builds understanding on electric circuits through hands-on activities and guided questions. The activity is designed such that questions are posed to children as they work on building circuits so that they are able to relate to the concepts better. The activity by itself is simple and the questions are important to drive in-depth understanding.

The activity is better done in pairs, as each child would get an opportunity for experimentation. Pre-activity questions given below can be used to engage the students and connect the activity to their prior knowledge. If the students lack understanding of charge, teacher can do the common charging by friction activity (Comb and Paper) with students to explain the force between charges. This can be used to explain the interaction of charges in the electric cell and wire. Children's learning can be assessed using the circuit they build during the activity by simulating problems that affect the functioning of circuit asking the children to troubleshoot. Assessment part also includes a pictorial problem to assess the children’s understanding of circuits. Assessment should be done as and when children build and troubleshoot circuits.

6. Activity: Building Electric Circuits

Duration: 90 minutes.

Mode of activity: Group activity with two members per group.

Precautions:

• Never try this with the electric current flowing in the wires at your home/class.
• Never connect the positive terminal of the battery to negative terminal directly and vice-versa as it will cause the battery to lose the charge quickly.

6.1 Objective:

In this activity, children will build electric circuits and be guided to understand functional difference between series and parallel circuits. They will learn to represent an electric circuit using symbols.

a. Suggested Pre-Activity Questions:

The following questions can be used to initiate a classroom discussion and the activity will be followed by more engaged discussion in class through questions

• How does the light in our room glow?
• What are the components required to light up this small electric bulb (show the bulb to children)?

6.3 Observables:

During the course of the activity students must observe status of bulbs (ON/OFF), condition of circuit components, and condition of connections as they are vital in building circuits as well as for the purpose of troubleshooting.

4. Procedure for conducting Activity:

1. After eliciting from students the components required for lighting up a bulb, the components should be given to the students.
2. The students build up the circuit on their own
3. Now the teacher asks questions to lead the students to an understanding on the components required for building an electric circuit: Power source, Load (Anything that uses the electricity from source, example: electric bulb, fan), Switch, and Connector. The functions of each component can be elicited by asking the question ‘what if it is not there?’
4. What makes the light glow?
1. Children may come up with answers like current, electricity, from the connection of electric cell to the bulb makes the bulb to glow, etc. Now the teacher should guide them through questions.
1. What is the nature of electric current and ask how does it flow from battery? Teacher should also enquire about the positive and negative terminals of the battery and relate them to the types of charge in static electricity.
2. Does the wire also contain charge?
3. What will happen to the charge in wire when placed in contact with the battery terminals?
4. In this level, the students should understand that charges in the wire get repelled by the charge on the battery cause the charge to flow. Explain that this flow of charges is current. (Learning outcome 1)
5. The teacher should show alternative connections and illustrate the difference between the open path and closed path to make children to arrive at the definition of electric circuit. The teacher should make children focus on the similarity between the words circuit with circle and aid them in building scientific vocabulary.
5. Now, the teacher should give two bulbs to each pair and ask them to make the two bulbs glow.
6. Children would come up with a series or parallel type of connection.

After they do:

The teacher should pull out a bulb from a parallel circuit and pose the question: How will you connect the bulb, if you want one bulb to go off when the other bulb is removed? Alternatively, how will you connect the second bulb, if you want it to be ON even if the first bulb is removed? the teacher should guide the students if they are not able to do on their own. The teacher asks   them about the requirements for each bulb to turn ON or OFF (Learning outcome 2).

The teacher can assess the student learning by doing the following:

• The teacher should insert a fused/damaged bulb in a series circuit and parallel circuit. Ask students to give reason as to why the bulb glows or does not glow in the above situations.
• In series circuit, when a fused/damaged bulb is inserted in the circuit, second bulb in the circuit stops glowing and in a parallel circuit even after fused/damaged bulb is inserted in the circuit, the second bulb in the circuit continues glowing.
• Connect a damaged switch in the simple circuit. Ask students to find out why the bulb does not glow.
• Connect a useless cell in a circuit so that bulb in the circuit stops glowing.  Ask students to find why the bulb does not glow?
• Ask children, "how will you explain this to your friend who doesn’t know the connections if you cannot give her/him a face to face explanation, or talk to her/him over phone." This discussion will lead to students understanding that drawing is a form of representation and now students should come out with their own representations.
• Enquire about the difficulties in using such form of representations. Children may come up with difficulties like time consuming, unable to understand other drawings.  Ask them about overcoming difficulties. Then, introduce them to symbols of electric circuits.(Learning outcome 3).

6.5. Post-Activity Questions:

These questions have to be posed to each of the pair:

1. What is electric current?
2. What are the components required to build an electric circuit and the function of these components in electric circuits?
3. What are the advantages of representing a circuit with symbols?
4. What is the difference between series and parallel connections?
5. When you turn off a light at your home, do all lights turn off? Can you guess what kind of circuit it would be? Can you reason out why it is so?
6. Where does series circuit find application?

7.  Worksheet: Electric Circuits

7.1 The teacher gives the following connection arrangement to the students and asks them to identify the cases in which the bulb will glow and explain why in some cases the bulb does not glow and in some other cases, the bulb glows?

8. Rubric

 Performance Indicator 4 3 2 1 Components and their functions Names all the four components and explain their functions Names three components and explain their functions Names two components and explain their functions Only names the components but not able to explain their functions. Build Circuit Builds simple, series and parallel circuits and explains the difference Builds simple, series and parallel circuits, but does not explain Build only simple and either series or parallel. Builds only simple circuits. Draw circuit Ability to provide their own representation and also with all symbols. Ability to provide their own representation and with two symbols. Ability to provide their own representation with only one symbols Able to provide their own representation only without symbols. Troubleshooting (Damaged bulb, switch, battery, connection arrangement) Identify the issues in all the four components. Identify the issues either in three of the components. Identify the issues either two of the components. Unable to identify only one of the issues.