Physics - Magnetism: Flashcards
Names of magnetic materials.
Iron (Fe)
Cobalt (Co)
Nickel (Ni)
Some metals are made out of magnetic materials making them magnetic, but they aren’t really magnetic materials, an example of this is steel.
Non-magnetic materials examples
Aluminium
Copper
Silver
NOT ALL METALS ARE MAGNETIC
ONLY MAGNETIC MATERIALS CAN BECOME MAGNETS
Difference of magnet and magnetic material
1 end attracts. £Bothends have to attract because the magnet would…
A magnetic material can become a magnet
All materials that are magnetic attract to a magnet.
WHAT MAGNETIC MATERIALS ARE MAGNETS AND WHAT MATERIALS ARE JUST MAGNETIC MATERIALS:
MAGNET: MAGNETIC MATERIAL:
…induce/transfer… #1 end *repels*. …opposite poles onto magnetic material, if North Pole touches…
…magnetic material then magnetic material turns south and vice…
…versa - not permanent magnet.
£**No**ends can **repel**
£**No** ends can have the force of **repulsion**
£**All** ends *have to* have the force of **attraction**
See law of magnetism for more info.
Types of pole
- NORTH-SEEKING POLE/NORTH POLE (N)
- SOUTH-SEEKING POLE/SOUTH POLE (S)
All magnets have 2 poles, one of each type (see above). Can not EVER have magnet with ONE pole.
Magnetism is strongest at…
…the poles
THE LAWS OF MAGNETISM
Magnets can exert forces on other magnets
Like poles (n and n also s and s) repel
Opposite poles attract
Magnets can exert forces on unmagnetised magnetic materials
Both poles always attract unmagnetised magnetic materials.
THE LAWS OF MAGNETISM 2: …Both poles attract to unmagnetised magnetic materials because…
Temporary poles have to be transferred onto iron nails/unmagnetised metal materials.
See Physics - 2ND FORM - MAGNETISM REVISION in photos if got yellow or under.
LAWS OF MAGNETISM 2:
For both poles to always attract temporary poles must be transferred onto iron nail/unmagnetised
object
Magnetism is strongest at its poles
LAWS OF MAGNETISM EXPERIMENT:
1.take 2 watch glasses and arrange a bar magnet on the top.
2. Take another magnet and bring the 2 north poles together notate what happens (do not bring them close together so that they ‘stick’ together/repel away).
3.bring south and south together and notate what happens (do not bring them close together so that they attract together/repel away)
4. Bring the North Pole to the South Pole notate what happens (do not bring them close together so that they ‘stick’ together/ repel apart)
5. substitute bar magnet for unmagnetised iron nail and bring the North Pole, then the south after, to the unmagnetised iron nail notate what happens (do not bring them close together so that they attach together/ repel apart)
SEE PHOTO OF WATCH GLASSES TOGETHER IN MAGNETISM PHYSICS REVISION - 2ND FORM IN PHOTOS.
Recall a brief summary of LAWS OF MAGNETISM PROVING EXPERIMENT
- Put bar magnet on 2 watch glasses
Add second magnet and…
…2. Record results of:
@ put north and north together
@ put south and south together
@ put north and south together - Replace magnet with unmagnetised iron nail and
@ put north towards 1 end of nail
@ put **south*& towards 1 end of the nail
4.Record results - SEE DIAGRAM IN MAGNETISM PHYSICS revision - 2ND FORM IN PHOTOS HAVE TO DO.
To induce a Pole…
…one must use a permanent magnet (that they know is a magnet for sure) and bring it towards an magnetic material.
Experiment to test for whether a magnetic material is a magnet or non-magnetic material
- Take a bar magnet (permanent) and bring close to material if both the north and south ends attract to the bar magnet then the material is a magnetic material.
- Non-magnetic materials don’t attract or repel when near a permanent magnet.
- Take a permanent magnet and bring close to material
If 1 end repels and 1 attracts to permanent magnet then material is a magnet
Bar magnets and horseshoe magnets are…
…permanent magnets
Experiment for magnetism
IF object/material + bar magnet = attracts, it is a magnet.
ON THE OTHER HAND, IF object/material + bar magnet = NOT REPEL (the object/material can only attract or do nothing unless it is a magnet) nothing happens, then it is nota magnet
/strength of the forces…
…vary from the distance form the poles
Experiment: strength of magnet
- Weigh iron block with no extra force actions on it use weight as control variable
2.clamp a bar magnet above the iron block (5mm) note the mass.
3, repeat but make the distance 10mm, 15mm etc (5 up each time) and measure mass each time.
MAGNETIC FIELD
The space around a magnet where forces are felt.
Can be plotted and drawn as a diagram
Diagram of magnetic field gives information about the size and direction of the magnetic force.
Plot and draw magnetic fields
Use iron filings:
1, pour iron filings onto paper with bar magnet underneath
2, gently tap edge of paper until lines start appearing.
3, The lines of magnetic field may not be fully formed - need large paper.
Using compass:
1, stick the bar magnet down on paper.
2, choose a point touching the magnet and draw a dot
3, use compass, align the north needle with the dot and draw another dot where the end of the needle (south) is pointing
4, repeat all round the magnet.
See Photos in MAGNETISM PHYSICS REVISION -2ND FORM
Magnet field lines go from…
…North to south SEE MAGNETISM PHYSICS -2ND FORM IN PHOTOS PLEASE.
SEE MAGNETISM PHYSICS -2ND FORM IN PHOTOS AND CONCENTRATE..
..know how to interpret field diagrams
Compass - how it works
Arrow inside of it = a small and vey lightmagnet with poles
Low weight helps it to rotate freely.
Arrow points in the directions of the MAGNETIC FORCE MAGNETIC FORCE
North + south = attract
North-seeking pole of compass doesn’t point directly to South Pole.
SEE PHOTOS - MAGNETISM PHYSICS-2ND FROM
Earth has…
It’s own magnetic field.
The motion of liquid iron outer core generates Earth’s magnetic field
On a compass/ really light magnet with no friction/ forces acting against it, the North Pole is actually the north-seekingpole meaning it seeks north and because earths poles are flipped it means the north-seeking pole is pointing to earths South Pole
See photos magnetism physicsi 2nd form
A compass points…
…to Earth’s south geographical poel
How to make temporary magnet and electromagnet:
1.Take 1metre of insulated copper wire and wind it around an iron nail make sure you have 10cm of wire either end of coil (equal length) make sure copper wire is pushed in together.
2. Take copper wire off and attach either end of wire with crocodile clips to a wire and then to a power supply in the side saying D.C. (Direct contact
3. Set power supply to 3 and don’t turn on, use compasses either side of copper wire record results.
4. Turn on power and see how compasses change record results.
5, has become temporary magnet (when electricity is flowing through it).
SEE MAGNETISM PHYSICS -2ND FORM PHOTOS please.
ELECTROMAGNET: the link between electricity and magnetism
How to make a compass
- Get a bar magnet and leave it there on that desk to rotate north BUT
it won’t because the friction between the magnet and desk oppose the motion of the bar magnet hence friction can compare pt the force of earth’s magnetic field upon the bar magnet.
So:
1, Place magnet in two watch glasses like so:
🌗 🌓 🧭the black is the watch glasses and the compass is the bar magnet.
2 The magnet should spin by itself but if it doesn’t after a while, nudge it gently
3.note direction the North Pole of the magnet points and compare to real life google’s north/compasses north (away from magnets and watches etc.)
4. See accuracy
Permanent magnet vs Temporary magnet
PERMANENT:
Hard magnetic materials like steel that are almost impossible to demagnetize and magnetize
TEMPORARY:
Soft magnetic materials like iron that are easy to demagnetize and magnetize
When picking up a magnetic material it will induce opposite poles so the magnet and material attract.
Making a permanent magnet
- Take a steel pin and use a bar magnet to stroke the pin with *north end of magnet in a wide arc many times, lifting the magnet high when returning to the beginning of the stroke - one touch method
2.use working compass to check that the pin has one north and South Pole
See MAGNETISM PHYSICS - 2ND FORM REVUISION IN PHOTOS PLEASE.
Hard magnetism
A Magnetic material that is hard to demagnitize and magnitize aka permanent magnet e.g. steel
Soft magnetism
When magnetic material is easy to demagnetize and magnetize aka will become temporary magnet e.g. iron
Destroying magnets
(Aka demagnetising the magnet)
Destroy by:
Heating magnet
Hitting magnet
See MAGNETISM PHYSICS - 2ND FROM IN
HOTOS REVISION PLEASE.
DOMAIN THEORY
Domain = group of atoms with magnetic poles, represented as arrow, the top of the arrow being north end.
SEE MAGNETISM PHYSICS REVISION - 2ND FORM IN PHOTOS
To make an electromagnet:
Wrap coils of wire around an iron core (iron nail for even more simple experiment) with an electric current flowing through the coils of wire (not through the core AKA the nail in even more simple experiment).
To make a solenoid
1.Wrap coils of wire around an iron core with an electric current flowing through the wire (not through core).
2. Remove core.
3. If there is still a magnetic field around the coil of wire whilst an electric current flow then it is a solenoid now (if this happens and there is no core)
Difference betep
Difference betep
Uses of magnets
Fridge magnet purse clasp compass
Dependent variable
Changes depending on the independent variable
Independent variable
The thing you choose to change
Control variable
Thing/s that stays the same to keep experiment as ‘fair’/ even as possible
‘Fair’/ Equal test
Keeping the same things the same each time you do the test.
Keep everything the same except the independent variable (dependent variable will change automatically because of independent)
Range
The lowest to the highest number (not including anomalies - abruptly different result/s).
Interval
Gap between readings/ The gap between two lines on a measuring cup
See booklet for experiments
Difference between solenoid and electromagnet
Solenoid = magnetic field around a coil of wire when an electric current flows yet there is no core (iron nail here). Electromagnet is the same but with a core (iron nail here).
Iron is a soft magnetic metal also a soft magnetic material
Steel is a hard magnetic metal also a hard magnetic material
