To make an electromagnet stronger The 3 C’s More Coils More Current Use an iron Core Can you copy this please? 1
Last lesson Field around a wire Electromagnetism Investigation
Moving charges (currents) Moving charges (electric currents) also produce a magnetic field Conventional current – electrons flow in the opposite direction http://www.sciencebuddies.org
Magnetic field around a straight wire You can use the right hand screw rule to decide which direction the field goes Stronger field closer to wire
Magnetic field around a straight wire You can use the right hand screw rule to decide which direction the field goes Can you copy this? Stronger field closer to wire
“Making electromagnets Investigation”
To make an electromagnet stronger?
To make an electromagnet stronger The 3 C’s More Coils More Current Use an iron Core
Today’s lesson Field patterns around a wire, solenoid and coil. The motor effect Making a loudspeaker
Field around a solenoid (coil)
Field around a coil
Can you gather around Mr Porter?
Can you copy this sentence into your books please. The Motor Effect When a current is placed in a magnetic field it will experience a force (provided the current is not parallel to the field). This is called the motor effect. Can you copy this sentence into your books please.
The Motor Effect The direction of the force on a current in a magnetic field is given by Flemming’s left hand rule. Thumb = Motion First finger = Field direction Centre finger = Conventional Current
The Motor Effect Can you copy this please? WITH DIAGRAM! The direction of the force on a current in a magnetic field is given by Flemming’s left hand rule. Thumb = Motion First finger = Field direction Centre finger = Conventional Current
Sample question In this example, which way will the wire be pushed? (red is north on the magnets)
Sample question In this example, which way will the wire be pushed? (red is north on the magnets) Current Field
Can you gather around Mr Porter? Again?! 18
Building a loudspeaker These also use the motor effect Coil in here magnet
Let’s read! Pages 210 and 213. The answer the questions on all pages. Finish for homework due 15th October