Aquila Children's Magazine The Electric Issue - Page 9

MAKE THE DISC THE SCIENCE BIT 9 With a pencil, draw a circle approximately the same size as the copper coil on a piece of paper and cut it out. Motors convert electrical energy (in this case, from the battery), to mechanical energy, which is used to cause rotation. 10 With a sharp point, pierce a small hole at the top and bottom, and trim the sides so they fit between the knots in the coil. 11 12 13 14 When a wire carrying current is placed in a space with a magnetic field, the wire experiences a force. The size of the force depends on three things:  The amount of current in the wire  The length of the wire  The strength of the magnetic field Draw a bird on one side. Draw an upside down birdcage on the other side of the circle. Colour the disc in whichever way you prefer. Direction of current Cut two shorter lengths of copper wire and use them to connect the disc to the rotor. Coil is wound clockwise N S Magnetic field (North pole up) Front view The direction of the force depends on two things:  The direction of the current  The direction of the magnetic field CONNECT IT UP 15 Slot the ends of the copper wire through the loops in your paper clips. The coil should spin freely. 16 Pick up your magnet, hold it in front of the coil. Give the coil a little spin to get it moving. N S Force Force N S Magnetic field (North pole up) Side view When the rotor is given a spin, the uninsulated (stripped) sections of the wire come into contact with the current. The circuit is complete and current flows through the rotor. When the rotor spins, the paper clip comes into contact with the insulated bit of the wire, causing the circuit to be broken. Now current is not flowing, instead the inertia from the initial movement carries the coil the rest of the way so the uninsulated bit of wire reconnects the circuit and the process begins again. The coil spins, turning the image over and over again, and your eyes do the rest. AMAZING! 9