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1.7

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by banu

Introduction

Set up a circuit using AA batteries and an LED to test the electrical conductance of different material from daily life.

Video Overview

    • Scissors have functional sharp edges. Contact may result in injury.

    • Always keep blades away from fingers and body. Handle with care.

  1. To make the battery holder please visit this link DIY Battery holder - Foam and Spring.
    • The longer leg is the positive terminal.

    • Connect the wire from the negative terminal of the battery to negative terminal of the LED.

    • Attach another wire to the positive end of the LED. Keep the other end free.

    • Remove insulation from both the ends of the wires before you connect to LED or battery.

    • Keep the wire from the positive end of the battery free.

    • We are going to use the free ends to check the conductivity of different materials.

    • You can also keep a longer wire ready to attach it on the positive end. This is only useful for checking bigger objects.

    • The wires are now your test leads.

    • Use these test leads to test various materials for their conductivity. Never bring the test leads in contact with each other; keep them at least 2-3cm apart on every object that you test.

    • If the LED does not glow, it is an example of a negative result, in this case the material is an insulator.

    • If the LED glows, it is an example of a positive result, in this case the material is a conductor.

    • The connections between the battery and safety pin might be loose, in that case hold the two terminals with your thumb and index finger for a better connection.

    • Make sure all the connections are clean and stable, otherwise the current will not flow.

    • To ensure proper connection, wind the wire several times over the material.

    • Does the brightness of the LED vary among different conductors?

    • Conductivity is directly proportional to brightness of the LED. (True/ False)

    • Are all metals conductors, and all non-metallic substances insulators? (Yes/No)

    • Can an LED be connected in any direction and still work? Can you think of any other use for this property of the LED?

    • Why is it important to connect the batteries as we did here? Are there other ways of connecting multiple batteries?

    • Use the observation table shown alongside to classify the materials into good and bad conductors and insulators.

    • Good conductor - LED glows brightly. Bad conductor - LED glows dimly. Insulators - LED does not glow.

    • Try to check some bigger materials like iron rod, bicycle wheel rim, cricket bat etc.

    • Try to check the conductivity of liquids like milk, curd, lemon juice or any other fruit juice.

    • If you want to check the conductivity of even more materials, please click on this link Electrical Conductivity (Variations).

Finish Line

Vishal Bhatt

Member since: 04/26/2017

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