Strand:Energy and Forces

Lesson: The Electric Bell

 
Aim/Objectives

Aim: To make children aware of the relationship between everyday objects and scientific principles

Objectives: To explain how an electric bell works.

Materials Needed
Textbook: Look Around - 6th class - Folens
Software: The Way Things Work (D.K. Multimedia)
Laptop, Projector, Extension Leads, Screen
Content/Methodology

Introduction

Elicit what children already know about electric current.

Development


Sequence of events:
(a)Laptop, projector set up on trolley before lesson begins. Get child to insert CD 'The Way Things Work (DK Multimedia). Click on index. Type in Electric Bell. Press OK. View demonstration of how electric bell works. Click on 'How it worked.' Click on words current, contacts, electro-magnet, and spring.

(a) When you press the doorbell, you connect two electrical contacts and electricity is switched on. Current flows around a circuit. A hammer is attached to an electromagnet. As it goes towards the electromagnet, it hits the bell.

(b) When the bar of the hammer hits the magnet, it breaks off the flow of electricity to the electromagnet. The electromagnet loses its magnetism. The hammer goes back to its original position. The cycle repeats as long as the visitor presses the bell.

Conclusion/Follow Up Activities

Questions and Answers session. Take suggestions as to how workings of the electric bell could be enacted or dramatised. Choose a group or groups to do so at a later date.

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