Download 4th grade Physical Science Part 2

4th grade Physical Science
Part 2
L.O. I will describe how magnets
and electromagnets work.
DAY 1
• Magnets will attract certain metals
• Permanent magnet – an object that
keeps magnetism for a long time
• Temporary magnet – will lose magnetism
after a short time
• *Magnetic Poles – areas where the force
of the magnet is greatest
• *Bar and horseshoe magnets – pole is at
the ends
• Ring magnet – pole is on the face
• *A compass is a free floating magnet
that will always point North
• *Like poles REPEL – push away
S
N
N
• *Opposite poles ATTRACT – pull together
Magnetic Earth
• Earth’s center is made up mostly of
molten iron
• As Earth spins, the iron particles line
up, producing Earth’s magnetic field
• *So Earth is like a gigantic bar magnet
• *It is surrounded by a magnetic field
with lines of force
Day 2
• *Electricity can produce magnetic fields
• This is called an electromagnet
• When the electric current passes
through the wire, the current produces
a weak magnetic field around the wire
Iron nail
wire
Power source
switch
– *To make the electromagnet stronger you
can
• *wrap more wire around the iron nail
• *use more batteries or bigger batteries
– If I take the batteries out or turn the
switch off, the nail loses it magnetism
• *Electrically charged objects will become a
magnet and will either attract or repel
• A motor will make a fan move
• *An electric motor changes electrical
energy into energy of motion
• They use electromagnets and permanent
magnets by using like poles to repel and
the opposite poles to attract, making the
motor move
• *Electrical energy will convert to light,
heat, and motion