How Conduction Works C onduction is the transfer of heat or electricity from two substances that are in direct contact (that is, touching one another). Different materials have different properties, which makes some better conductors than others. If we zoom in on an object, we will see that it is made up of closely packed individual atoms. These individual atoms, in turn, are made up of a nucleus surrounded by layers of electrons. In metals and other good conductors, the last layer of electrons – also known as the “valence electrons” – are very loosely held together. These electrons are so loosely held together that they are considered “free electrons” since they are free to move around in the space between neighboring atoms. Normally, these free electrons just move around with no particular direction. But they can also be made to move around in an orderly way through a conductive material. Just like water flowing through an empty pipe, electrons are also able to move within the empty space within the atoms of a conductor. This orderly flow of electrons is what we call electricity, or electric current. As each electron moves through the atoms in a conductor, it pushes the one ahead of it so that all the electrons move together as a group. Imagine a pipe filled with marbles. The pipe is the conductor, while the marbles are the electrons. SALAGUINTO Grade 6 Vol. 22 No. 4 e-Pages 2 If a single marble is inserted into the left side of the pipe, it creates a chain reaction and another marble immediately exits on the right side of the pipe. Even though each marble traveled only a short distance, the transfer of motion through the pipe happens almost instantly, no matter how long the pipe is. If we want electrons to flow in a certain direction to a certain place, we must provide a path for them to move, just as a plumber must install piping to get water to flow where he or she wants it to flow. Remember that electrons can flow only when they can move in the space between the neighboring atoms of a conductor. This means that conduction can only happen when there is an unbroken path provided by the conductive material, providing a way for the electrons to travel through. Sources: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/conins.html www.allaboutcircuits.com SALAGUINTO Grade 6 Vol. 22 No. 4 e-Pages 3 WORD FIND ACTIVITY 1: Conduction Identify what are being described by the following sentences. Find the answers in the box. P A T H O T A X C O Y A C O I L E M T O E T R O Y T I L O Y N K I K E L E C N D U C T U N D E R C R Y F R L Y G A E E C T R O U T F A R S V I W N D U C T O I A M E O C I R T C T I M E R N K U R L E R O I T O S E C P H L I N D E S I G N Y C E 1. Transfer of heat or electricity from two substances that are in direct contact. 2-3. Individual atoms are made up of a ________ surrounded by layers of ________. 4. Valence electrons are also called ______ electrons because they can move around in the spaces between neighboring atoms. 5. The orderly flow of electrons is called electric current or ________. 6-7. As each electron moves through the atoms in a __________, it pushes the one ahead so all the electrons move together as a ______ ___. 8. If we want electrons to flow in a certain place, we must provide a ______ for them to move. Answers: 1- conduction 2- nucleus 3- electrons 4- free 5- electricity 6- conductor 7- group 8- path A C T I V I T I E S SALAGUINTO Grade 6 Vol. 22 No. 4 e-Pages 6