The appliance of science Lesson objectives: To explain how an electromagnet works. To discuss how a relay uses a small current to switch on a much larger.

Slides:



Advertisements
Similar presentations
NATE and Cole's information Period Electromagnets Currents in wires create a magnetic field around the wire By turning the current on and off,
Advertisements

LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON.
Magnetism Click to move on Mike Turner, Feb
Science/Foss Unit Study Guide Magnetism and Electricity 4th Grade Rutherford Elementary School Ms. Blair Room 205.
8B1 Electromagnets Application. TITLE: Electromagnets Objectives: To be able to label (level 4) and describe how an electromagnet works including its.
P.50 Magnetic effect of a current P.50 North pole and South Pole.
OBJECTIVES: WARM-UP: More batteries/volts
Electromagnets In Bells & Relays D. Crowley, 2008.
Magnetism Aurora. Where can we find a magnetic field? Around a permanent magnet Around the conductor which carry current e.g. Electromagnets All magnets.
USING ELECTRICITY – Class 7 MAGNETIC EFFECTS OF ELECTRICITY Done by Mrs. Aparna.S.
Electromagnets Grade 8.
MAGNETISM.
Technician’s List Demos
© NTScience.co.uk 2005KS3 Unit 8j – Magnets and Electromagnets 1 Magnets and Electromagnets.
6.11 Vocabulary Electromagnet: type of magnet in which the magnetic field is produced by a flow of electric current Core: metal (iron) center of an electromagnet.
MAGNETISM AND ELECTROMAGNETISM
Unit: Energy and Control- Electricity.  English Scientist William Sturgeon invented the first electromagnet in He wrapped a coil of wire around.
How is a permanent (reg.) magnet different from an electromagnet?? Describe how an electromagnet shows how magnetism & electricity relate to each other.
Magnetism from Electricity Objectives: Describe the relationship between an electric current and a magnetic field. Identify common devices that demonstrate.
Electromagnetism How can you make an electromagnet?
MAGNETISM.
© OUP: To be used solely in purchaser’s school or college 8J Magnets and electromagnets Magnets Magnetic fields 8J Magnets and electromagnets Electromagnetism.
Electromagnets Science Unit 1 Lesson 5 4 th Grade Miss Young.
Magnets and Electromagnets
Electromagnets D. Crowley, 2008.
What is Electromagnetism Chapter 3 Section 1 Pages
P3 Electromagnetism Revision. Electromagnetism How do you make an electromagnet? Insulated wire wrapped round a soft iron core. When current applied a.
Magnets and Electromagnets
d Calculating the magnetic field strength around a current carrying wire: B= Magnetic field strength [T] I = Current [A] d = Distance [m] Right hand.
8J Magnets and Electromagnets
Learning Objectives I can describe electromagnetism, solenoid, and how they work. I can explain how a magnetic field can make an electric current through.
                                                                  Electro Magnets.
Investigation 4: current attractions
Electromagnets.
What is different about this magnet?
18 June, 2018 Magnetic fields.
Using Electromagnets 8-Nov-15
Electromagnetism.
Using Electromagnets 8-Nov-15
True or False Field lines show the direction of travel for a negatively charged object. Hitting a magnet will a hammer with magnetise it Magnetic field.
Teacher’s Notes A slide contains teacher’s notes wherever this icon is displayed - To access these notes go to ‘Notes Page View’ (PowerPoint 97) or ‘Normal.
BASIC PRINCIPLE When electricity flows in a wire a magnetic field is formed around the wire. The stronger the current the stronger the magnetic field will.
Draw a diagram that shows the magnetic fields that result when like poles of two magnets are close to each other when unlike poles are close. Use lines.
Electromagnets.
In This Section We Will Be Studying These Topics:
Teacher’s Notes A slide contains teacher’s notes wherever this icon is displayed - To access these notes go to ‘Notes Page View’ (PowerPoint 97) or ‘Normal.
Teacher Imarlys Cajigas 5th grade Science
Magnetic or non-magnetic?
No current, compass points to north Current, compass deflected
Electromagnets Lesson 3
Teacher’s Notes A slide contains teacher’s notes wherever this icon is displayed - To access these notes go to ‘Notes Page View’ (PowerPoint 97) or ‘Normal.
Name: _________________________
Magnetism and electricity
Can an ordinary nail be a magnet?
Magnetism from Electricity 18.2
Learning Objective To be able to:
This is a little summary note on electromagnets
Electromagnetism.
Presentation transcript:

The appliance of science Lesson objectives: To explain how an electromagnet works. To discuss how a relay uses a small current to switch on a much larger current. Key words: Current, relay, electromagnet

Electromagnet Can you think of a type of magnet that can be turned on and off. Watch the following video clip and write instructions on how to make an electromagnet.

Magnetic effects of current

Making an electromagnet

Investigating electromagnets The strength of an electromagnet depends on whether it has a core of iron. Two experiments can be carried out to investigate the other factors that can affect the strength of an electromagnet: Investigate how the number of coils affects the number of drawing pins attracted to an electromagnet – keep the current the same in this experiment. Investigate how the size of the current affects the number of drawing pins attracted to an electromagnet – keep the number of coils the same in this experiment.

How an electromagnet works An electromagnet is made by using electricity to make a piece of iron magnetic. When a wire has an electric current running through it, the current creates a magnetic field. If you twist the wire into a coil, the magnetic field has the same shape as a bar magnet. A piece of iron in the core makes this core field stronger.

How could you use the apparatus below to investigate the effects of changing the current and the number of coils on the strength of an electromagnet? Investigating electromagnets

Investigating electromagnets – results Here are some example results number of coils number of drawing pins attracted current (A) number of drawing pins attracted Describe the trend commenting on all results. (grade C) Mention how you made it a fair test and how you can improve your investigation. (Grade B/A)

number of coils number of drawing pins attracted Investigating electromagnets – analysis How did the number of coils affect the number of drawing pins attracted to the electromagnet?

Investigating electromagnets – analysis How did the size of the current affect the number of drawing pins attracted to the electromagnet? current (A) number of drawing pins attracted 50

Using electromagnets – recycling A large electromagnet is used on a recycling plant conveyor belt to pick up and move metal cans. What advantages does an electromagnet have over a permanent magnet? Which metals would the electromagnet attract?

Uses of electromagnets – electric bell When the circuit is closed, the electromagnet pulls the armature towards it, causing the hammer to strike the bell. The movement of the armature breaks the circuit, and the hammer returns to its original position. This sequence repeats, causing the bell to sound continuously. The circuit for a door bell includes an electromagnet.

Label the diagram – electric bell

Using electromagnets – door bells

A relay is a switch that is turned on and off by an electromagnet. An electromagnet used in this way is usually called a solenoid. Relays are used when a circuit with a high current needs to be switched on or off. Using a relay to do this means that a person does not have to touch the circuit with the high current in it.

Lifts, cars and other large electrical machines use high currents. Relays use an electromagnet to allow a small current in one circuit to control a large current in another circuit. Can you predict what will happen when the switch is closed in this circuit? Using electromagnets – the relay

Label the diagram – relay

Electromagnets: summary