Magnetism
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ST 4: Magnetism
3/25/2019
MAGNETISM To attract, or not to attract, that is the question…
Chapter 5, pg 163 - 168
A. Di Lallo CRHS 2019
1
ST 4: Magnetism
3/25/2019
Copy Me
What’s a magnet??? •
An object (or device) that gives off a magnetic field
•
Objects which contain iron, cobalt or nickel can be/are attracted by magnets
•
Wires can form a temporary magnet (electromagnet)
Copy Me
Why are some substances magnetic? •
Materials which can become magnetic are made up of regions called domains.
•
More domains becoming aligned = stronger the magnet
•
Align domains= place material inside an existing magnetic field
A. Di Lallo CRHS 2019
2
ST 4: Magnetism
3/25/2019
Did you know? The Earth is technically a big magnet! Recall that the Earth’s core is iron…and that iron is ferromagnetic! The geomagnetic field is actually extremely important in deflecting solar winds (which carry UV rays). Without it, solar winds would blow away the ozone layer
A. Di Lallo CRHS 2019
3
ST 4: Magnetism
3/25/2019
Copy Me
Types of Magnets 1.
Permanent magnets: Materials that are naturally magnetic → magnetite
2.
Ferromagnetic: Materials made from Iron (Fe), Nickle (Ni), Cobalt (Co) or an alloy of these materials which can become magnetic. They retain magnetic properties while under the presence of a magnetic field
3.
Electromagnet: Temporary magnets caused by a live current
Permanent Magnet Magnetite attracting pieces of iron
A. Di Lallo CRHS 2019
4
ST 4: Magnetism
3/25/2019
Electromagnet Substance temporarily becoming magnetic due to a live electric current
A. Di Lallo CRHS 2019
5
ST 4: Magnetism
3/25/2019
Copy Me
Magnetic Forces of Attraction and Repulsion •
There are two poles on a magnet: North and South •
•
North pole = End of magnetic that turns towards geographic North
Opposite poles attract, like poles repel!
Magnetic Forces of Attraction and Repulsion •
Opposite poles attract, like poles repel!
A. Di Lallo CRHS 2019
6
ST 4: Magnetism
3/25/2019
Figure 1. Polar Bears
Copy Me
Magnetic Forces of Attraction and Repulsion •
Force of attraction or repulsion = magnetic force
•
Magnetic field = area of space where magnetic force of one magnet can act on another
•
Magnetic field lines leave the north pole and come towards the south pole •
Field lines do not cross one another
A. Di Lallo CRHS 2019
7
ST 4: Magnetism
3/25/2019
Magnetic Field lines of a Bar Magnet
Iron Filings of Magnetic Fields
A. Di Lallo CRHS 2019
8
ST 4: Magnetism
3/25/2019
Magnetic Field lines of a Bar Magnet
Iron Fillings of Magnetic Fields
Attraction between poles
A. Di Lallo CRHS 2019
9
ST 4: Magnetism
3/25/2019
Iron Fillings of Magnetic Fields
Repulsion between poles
Iron Fillings of Magnetic Fields
Repulsion between poles
A. Di Lallo CRHS 2019
10
ST 4: Magnetism
3/25/2019
Magnetic Field lines of a Horseshoe Magnet
Iron Filings of Magnetic Fields
A. Di Lallo CRHS 2019
11
ST 4: Magnetism
3/25/2019
Copy Me
Electromagnetism •
Phenomena from the interaction of electricity and magnetism
•
Dynamic electricity produces temporary magnetic fields • •
•
Current flowing = magnetic field No current = no field
To determine direction of magnetic field = left hand rule
Copy Me
Left Hand Rule Thumb: Current Direction (Electron flow = negative terminal to positive terminal)
Fingers: Magnetic Field Direction
A. Di Lallo CRHS 2019
12
ST 4: Magnetism
3/25/2019
Left Hand Rule
A. Di Lallo CRHS 2019
13
3/25/2019
MAGNETISM To attract, or not to attract, that is the question…
Chapter 5, pg 163 - 168
A. Di Lallo CRHS 2019
1
ST 4: Magnetism
3/25/2019
Copy Me
What’s a magnet??? •
An object (or device) that gives off a magnetic field
•
Objects which contain iron, cobalt or nickel can be/are attracted by magnets
•
Wires can form a temporary magnet (electromagnet)
Copy Me
Why are some substances magnetic? •
Materials which can become magnetic are made up of regions called domains.
•
More domains becoming aligned = stronger the magnet
•
Align domains= place material inside an existing magnetic field
A. Di Lallo CRHS 2019
2
ST 4: Magnetism
3/25/2019
Did you know? The Earth is technically a big magnet! Recall that the Earth’s core is iron…and that iron is ferromagnetic! The geomagnetic field is actually extremely important in deflecting solar winds (which carry UV rays). Without it, solar winds would blow away the ozone layer
A. Di Lallo CRHS 2019
3
ST 4: Magnetism
3/25/2019
Copy Me
Types of Magnets 1.
Permanent magnets: Materials that are naturally magnetic → magnetite
2.
Ferromagnetic: Materials made from Iron (Fe), Nickle (Ni), Cobalt (Co) or an alloy of these materials which can become magnetic. They retain magnetic properties while under the presence of a magnetic field
3.
Electromagnet: Temporary magnets caused by a live current
Permanent Magnet Magnetite attracting pieces of iron
A. Di Lallo CRHS 2019
4
ST 4: Magnetism
3/25/2019
Electromagnet Substance temporarily becoming magnetic due to a live electric current
A. Di Lallo CRHS 2019
5
ST 4: Magnetism
3/25/2019
Copy Me
Magnetic Forces of Attraction and Repulsion •
There are two poles on a magnet: North and South •
•
North pole = End of magnetic that turns towards geographic North
Opposite poles attract, like poles repel!
Magnetic Forces of Attraction and Repulsion •
Opposite poles attract, like poles repel!
A. Di Lallo CRHS 2019
6
ST 4: Magnetism
3/25/2019
Figure 1. Polar Bears
Copy Me
Magnetic Forces of Attraction and Repulsion •
Force of attraction or repulsion = magnetic force
•
Magnetic field = area of space where magnetic force of one magnet can act on another
•
Magnetic field lines leave the north pole and come towards the south pole •
Field lines do not cross one another
A. Di Lallo CRHS 2019
7
ST 4: Magnetism
3/25/2019
Magnetic Field lines of a Bar Magnet
Iron Filings of Magnetic Fields
A. Di Lallo CRHS 2019
8
ST 4: Magnetism
3/25/2019
Magnetic Field lines of a Bar Magnet
Iron Fillings of Magnetic Fields
Attraction between poles
A. Di Lallo CRHS 2019
9
ST 4: Magnetism
3/25/2019
Iron Fillings of Magnetic Fields
Repulsion between poles
Iron Fillings of Magnetic Fields
Repulsion between poles
A. Di Lallo CRHS 2019
10
ST 4: Magnetism
3/25/2019
Magnetic Field lines of a Horseshoe Magnet
Iron Filings of Magnetic Fields
A. Di Lallo CRHS 2019
11
ST 4: Magnetism
3/25/2019
Copy Me
Electromagnetism •
Phenomena from the interaction of electricity and magnetism
•
Dynamic electricity produces temporary magnetic fields • •
•
Current flowing = magnetic field No current = no field
To determine direction of magnetic field = left hand rule
Copy Me
Left Hand Rule Thumb: Current Direction (Electron flow = negative terminal to positive terminal)
Fingers: Magnetic Field Direction
A. Di Lallo CRHS 2019
12
ST 4: Magnetism
3/25/2019
Left Hand Rule
A. Di Lallo CRHS 2019
13
