Name 3 ways you have used magnets this morning… Much easier than it sounds… Door latches Fridge door anti-slam Laptop lid Blender Drill (probably not this morning admittedly!) Electric screwdriver (probably not this morning admittedly!) Hard drives VCR (also fairly unlikely!) Some cars Chargers for almost everything

Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles.

What is a Magnet? Which of the following… A piece of iron Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. What is a Magnet? Which of the following… A piece of iron An object which can attract metal An object which creates a magnetic field An object which can interact with other magnetic fields, including aligning with them. Any material which can be made to have a magnetic field

Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. What is a Magnet? Magnetism is actually a very broad term which can (and should) be broken down further to be useful. Put simply a magnet is a material which produces a magnetic field. This could be a permanent magnet (e.g. iron fridge magnet), an electromagnet (e.g. scrap yard magnet), a paramagnetic material (e.g. water or liquid oxygen).

What is a Magnetic Field Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. What is a Magnetic Field A region in space in which a charged object will experience a non-contact force.

Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Permanent Magnets Permanent magnets, or ferromagnets, are those which retain their magnetic properties even once you take them away from everything else (i.e. other magnetic fields). These are generally made from; I_____ (f_________ m__________) C_______ N_________

Permanent Magnets Properties of permanent magnets; Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Permanent Magnets Properties of permanent magnets; Attract other magnets and may induce magnetism in them Force of attraction is greatest at the poles. Two like poles will repel. Two opposite poles will attract. Align to already existing magnetic fields (like the Earth).

Showing a Magnetic Field Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Showing a Magnetic Field Draw a simple bar magnet with plenty of space around it on a sheet of A4. In PENCIL sketch the shape of the field lines you predict. In pairs hold the paper above the magnet but do not let them touch. Meanwhile the other partner will sprinkle iron fillings onto the paper. Remove the magnet carefully by lifting the sheet and place down so you can sketch the field lines while the iron fillings are still there. Carefully put them back in the shaker.

Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Simulation

Magnetic Fields Key Ideas: Field lines never cross Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Magnetic Fields Key Ideas: Field lines never cross Field lines exit from North Pole and enter the South Pole The density of field lines is proportional to the magnitude of the force. The direction of the magnetic field is given by the direction of the force that would act on another north pole placed at that point.

Showing Magnetic Fields Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Showing Magnetic Fields Now use the same method again but this time… Use 2 magnets with like poles near one another Use 2 magnets with opposite poles near one another. Sketch it (roughly it’s quite a bit trickier) in your exercise book.

Specification Aims By the end of this lesson you should be able to… Describe what is meant by the term “magnet” and define a magnetic field State the basic properties of magnets Draw and interpret magnetic field lines surrounding magnets and combinations of different poles. Magnetic Fields

Name 10 ways you have used magnets this morning… Should be a doddle this time!

Based on the magnetic field alone what could this image be?

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide.

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. What’s Wrong? Field lines should exit at the North Pole

Where does the Earth’s magnetism come from? Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Where does the Earth’s magnetism come from?

Electrical current + Movement = Magnetic Field Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Magnetic fields in the inner core interact with the moving fluid iron in the outer core and produce small electrical currents. Electrical current + Movement = Magnetic Field “Self exciting dynamo” or a “geo-dynamo”

How things work… How does a compass work? Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. How things work… How does a compass work?

How things work… North Attract Vacuum Poles Align Iron Magnetic Field Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. How things work… Explain how a compass can be used to find the magnetic North of Earth. Your answer should include reference to the materials involved (6 marks) North Attract Poles Vacuum Align Iron Magnetic Field

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. How things work… Why when I hold a compass near to a metal object why does it stop pointing North?

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Domains and Magnets Magnetic materials are made of domains, small magnetic regions. When these domains align (right) the material will produce a large magnetic field. When they do not align (left) the domains cancel out and no magnetic field is created.

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Demagnetising Hitting a magnet with a hammer or similar will throw all the domains out of line and therefore demagnetise the metal. Heating to a high temperature has a similar effect.

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Making a Magnet Stroking an iron bar with a magnet will magnetise it. The stroking action aligns the “domains” forcing them all to point in the same direction.

Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Induced Magnetism Other materials can also have magnetism “induced”. Think of paper clips or pins, they will still be attracted to a magnet if placed within a magnetic field but wouldn’t normally have a magnetic field themselves. In this situation they act as a magnet, but only whilst in the magnetic field. This is called induced magnetism.

Testing magnets Follow these simple rules for testing magnets… Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Testing magnets Follow these simple rules for testing magnets… Objects that are made of unmagnetised iron, cobalt and nickel are attracted to either pole of a magnet, but never repelled. Objects which are not attracted to either pole are not magnetic You can only show that an object is a magnet if it repels another magnet.

Now complete the questions  Specification Aims By the end of this lesson you should be able to… Distinguish between permanent magnetism and induced magnetism. Describe how a compass works including details of the Earth’s magnetic field. Solve problems using the magnetic field lines around magnets as a guide. Now complete the questions 