Was it light or electricity in your house?

I am sharing my experiences when I tried to probe or demonstrate some basic concepts under electronics i.e. light and electricity, switch, conductor and insulator. When asked, “Was there light in your house yesterday?”, all the students replied "Yes".
When asked to justify their answer, their responses were - 
  • we get to know after switching on the electric appliances.
  • the running electric meter indicates the presence of electricity.
  • we get to know after looking at light on the power board.
  • if electric appliances do not get switched on it means there is no electricity supply.

I asked them again, “Was there electricity in your house yesterday?” Again they said a loud "Yes". 
I probed, “Was there a light or electricity in your house yesterday?” This question sort of confused them. Asked them to recall the concept of light (what is light?). 
After thinking and talking with each other’s they responded- 
“Light is a medium through which we see the objects. Sun, moon, candle light, torch, bulb, fire etc. are the sources of light”. 
By understanding the cognitive level of the students, here I did not introduce electromagnetic radiation. So, I asked them which one is appropriate “light or electricity?” They responded: "Electricity". Then I tried to explain them that light comes through electricity when we switch on the electrical devices such as bulbs, tube lights, television etc. After this I tried to highlight the two different context “scientific and social”. In social context we use light but in scientific context we used electricity.
The Concept of Switch
To explore this I asked, “What do you understand by switch?”
They replied, "The equipment that controls television, bulb, fan and other electrical appliances is called switch".
When probed what really does a switch do, there was deep silence. It was the time to do some hands on demonstration to break the silence.
The experiment consisted of  simple circuits, which includes a wood stand, two nails, wires, battery, bulb and different materials (metals and non-metals) as shown in picture.
The instructions were:
  • Take a bulb, nails, wires, wood, and battery & then connect them according to the circuit.
  • Use different things or objects as paper, plastic, nails, safety pin (paper clip), zinc metal, aluminum foil, wood etc. in between the two nails as shown in picture.
  • Try to connect these objects through nails and observe the bulb whether it glows or not? 
The students arranged the circuit according to the procedure and connect the two nails through various objects. After the activity students shared their learning or reflection which were:
  • When we used safety pins, aluminum foil, nail & Zinc metal the bulb glows. 
  • When we used paper, plastic & wood the bulb does not glow. 
  • Different objects play an important role for completing circuit. 
  • When circuit is complete bulb glows (in case of object written in first bullets) when circuit
    is not complete the bulb does not glow.
From their own reflections I tried to explore and explained them that
"Any device which makes and breaks an electric circuit is known as “SWITCH”. Here paper, plastic, nails, safety pin, zinc metal, aluminum foil, wood etc. act as switch because these all can be used for connecting or disconnecting the electric circuit.."
(diagrammatically it can be shown as above)
The 2 possible scenarios
Case 1
When there is no connection between two nails, the circuit is not complete therefore the electricity does not flow ahead and bulb does not glow. In this situation we say the switch is “OFF” and circuit is known as an open circuit.
Case 2
When there was connection between two nails, the circuit is complete therefore the electricity flows ahead and bulb glows. In this situation we say the switch is “ON” and circuit is known as closed circuit. 
Both these scenarios led to the grouping of objects into conductors & insulators.
When asked, "Is water a conductor?", there was a mixed response. But,science is in the doing! 
I gave them a hint that by using water as switch in earlier activity can we understand it's nature whether it is a conductor or insulator? The question was how can we use the earlier setup? After thinking for a minute some of the students replied by dipping wire in water and then connecting it between nails as designed in experimental setup (in that time they told aluminum foil and zinc metal) we can understand its nature i.e. if bulbs glow it means it is conductor otherwise insulator, on performing the above activity they observed that the bulbs glows. A sigh of relief was on the faces of the students, suddenly a voice came from behind that wires (aluminum foil and zinc metal) are already conductor of electricity so how we can say it happened due to the water. It created a temporary confusion among them for concluding whether it happens due to water or wire? 
One group of students said that we can use the bowl full of water and dipped the setup (without connecting nails with wire or anything else) in them, make water as connector. Those students took the bowl and arranged the set up accordingly and observed that the bulb glows. Thus they concluded that the water is a conductor of electricity. 
Notes to myself: There is too much emphasis on drill and rote learning and too little emphasis on observation, design, observation, analysis, argumentation and process skills in general. The aim of science education can be fulfilled truly if the science teaching-learning process is governed through practical approach. 


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