3-MAG-01

From MrReid.org Wiki
Jump to: navigation, search

Outcomes

  • Pupils understand that magnets exert forces on each other and other magentic materials. These forces can be magnetic attraction or repulsion
  • Pupils can plot a magnetic field around one bar magnet and two bar magnets (attracting and repelling)
  • Pupils can recall that iron, nickel and cobalt are elements can be magnetised when in a magnetic field and are known as ferromagnetic materials
  • Pupils understand that a domain is a small region of a ferromagnetic material that has its own magnetic field, which can be aligned
  • Pupils understand that the direction of a magnetic field line indicates the direction of the force on a test north pole placed in the field at that point
  • Pupils can see that a uniform field can be created between to attracting bar magnets

Specification References

6.2 recall that magnets repel and atract other magnets, and attract magnetic substances.

6.4 understand the term 'magnetic field line'

6.5 understand that magnetism is induced in some materials when they are placed in a magnetic field.

6.6 sketch and recognise the magnetic field pattern for a permanent bar magnet and that between two bar magnets

6.7 know how to use two permanent magents to produce a unifrom magnetic field.

Starter

Using the mini white boards, ask the pupils to draw a magnetic field around a bar magnet. Identify the two main points about drawing a magnetic field- the lines are continuous, they do not cross and they have arrows. Develop into a discussion about the direction of the arrows and what causes a magnet to have a magnetic field.

Demo the domains under a microscope and allow the pupils to make a note about the structure of a ferromagnet.

Main Body of Lesson

  • Knowing of the structure of a magnetic field around a bar magnet, the pupils predict and then create the magnetic field around arrangements of bar magnets using this worksheet. Magnetic field patterns are created by placing the magnets under a piece of blank white paper and then sprinkling iron filings over the paper. Identify neutral points on diagrams. Discuss the spacing of the lines- the closer together the stronger the magnetic field strength.
  • Use mini turntables or upturned watchglasses to show that N and N repel, S and S repel but N and S attract.
  • Discuss the general shape of the Earth's magnetic field and what other elements found in the Earth are ferromagnetic.

Plenary

  • A short clip looking at the Earth's magnetic field.
  • Use hovering paper clip to discuss the principles of magnetism covered in the lesson.
  • A nice problem here is the following: You have 3 objects which look and feel identical. One is non-magnetic, one is magnetic and the third is a magnet. How can you determine which is which? The key here is separating the last 2; the pupils should hopefully realise that repulsion is the key to this task.

Homework

  • Research into where magnets are uses in everyday life. 3 examples with explanations.

Additional Information

Resources Required

12 x pairs of bar magnets iron filings plotting compasses blocks of wood blocks of metal

Additional: Floating paper clip demo

Textbook References

  • Complete Physics pages 202-205.

Website References

Skills Addressed

Safety/Hazards

  • Goggles must be worn whilst pupils are using iron filings.

Notes