Building Electrical Circuits Constructing Pathways Purpose: to understand and demonstrate how electrical circuits work

Electrical Circuit Electrons flow through a circuit, or path, that generates heat, light or movement.

Parts of a Circuit Power source or supply

Parts of a Circuit Transmission device such as wires

Parts of a Circuit Device to do work such as something that generates heat, light or motion Motor

Building a Series Circuit

Circuit #1 Use two short wires and a light bulb to construct this circuit.

Circuit #2 Replace the light bulb with a motor.

Circuit #3 Using another short wire, add a light bulb to the circuit.

Circuit #4 Using another short wire, add a switch to the circuit.

Conductors / Insulators To test items for electrical conductivity. Free a wire from the light bulb and attach another to the battery. Using the two free wire ends, touch items from the test object bag. If conductive, bulb will light. Record results. How are these similar to magnetic properties?

Review What is a circuit? What is a series circuit? A switch should be in what position to allow the flow of electrons? What is a conductor? Challenge: Connect light blub to battery with only one (1) wire.

Parallel Circuit Using two light bulbs and several short wires, make this circuit. Light Blub Both bulbs should light up at the same time. How can you make the bulbs shine brighter? Switch Battery

Electromagnet, Part One Using the yellow wire, wind it around the top part of the large rivet or screw 20 times. Connect the ends of the yellow wire to the battery (optional – use a switch). Switch Battery

Electromagnet, Part Two Using the small washers, turn on your electromagnet and move as many washers as you can from one side of your circuit board to the other in one move. Count and record. Switch Battery

Electromagnet, Part Three Wind your electromagnet with 40 turns of the yellow wire. Again, move as many washers as you can from one side of your circuit board to the other in one move. Count and record. Switch Battery

Electromagnets, Record Data

Electromagnets, Graph Data Graph your data for the number of washers carried by your electromagnet for 20 turns and 40 turns. Based on your investigation, predict how many washers your electromagnet will carry if the wire was turned 30 times. ?

Review What is a parallel circuit? What is an electromagnet? Challenge: on the next slide, decide which circuits will NOT work and describe how you would fix one of them.

Clean UP Carefully take your circuits apart. Place all the items back into the tray. Be careful of the small objects. Group like objects together in the tray. If you are missing any parts, tell your teacher.

References http://www.bbc.co.uk/schools/scienceclips/ages/10_11/changing_circuits.shtml