Elementary Science Experiment: Exploring Magnets (May the force be with you!)
Laurie Starkey, Cal Poly Pomona ([email protected])
Magnetic Fields
A magnet is an object that has a magnetic field around it - an area that acts as an
invisible force that pulls (attracts) or pushes (repels) other magnets or magnetic
objects. The two ends of a magnet are described as poles and are described as
+ and – or north and south. Materials can be magnetized by exposure to
magnets or to electric currents - once an object is magnetized it will act as a
magnet and exert its own magnetic field. A coil of wire with an electric current
flowing through it becomes a magnet, called an electromagnet. Spinning objects,
such as the earth, act like magnets and create a magnetic field; the North and South
poles describe the "ends" of the giant magnet we live on, and the magnet in a
compass will align with the earth's magnetic field so you can determine which
direction is north (the north end of a magnet will point to the earth's North Pole).
Certain materials are strongly attracted to magnets, such as iron and steel; these
materials are described as being ferromagnetic. Everyday magnets, like the ones
on your fridge, are ferrite magnets (made from iron). Very strong rare-earth
magnets are quite expensive but lots of fun to play with (they are made from
neodymium...can you find Nd on the Periodic Table of the Elements?). Observe
how iron filings, paper clips, or staples organize themselves in a magnetic field.
Opposites Attract!
Opposites attract, so the north end of one magnet
will be drawn toward the south end of another
magnet. When the same poles of two magnets are
brought together, they will be repelled from one
another - and will push apart (e.g., if the north end
of one is brought to the north end of another). Try
labeling the magnets shown. Observe what
happens when a pencil is put through several ring
magnets: they will all stick together or will
"magically" float as they push away from each
other. Also, observe the way a magnet pendulum
swings as it experiences magnetic fields.
bar magnets have a north pole and a south
pole (can also be labeled with + and -)
repel
N N N NNN N NNN
SSS SSSS SSS
N N N NNN N NNN
SSS SSSS SSS
attract
repel
disc/ring magnets
have a north face
and a south face
Eating nails for breakfast?!
Iron is an important element that is essential for your health. Red blood cells have
an iron-containing protein in them (called hemoglobin) that allows blood to
transport oxygen throughout your body. Hemoglobin is also what makes your
blood red! Iron-rich foods include meat, fish, beans and spinach. In order to
provide more iron in our diet, many foods are fortified with iron, meaning iron is
added. The iron that has been added to breakfast cereals can be isolated using a
magnet! If cereal is crushed and stirred with water, then a magnet can be used to
attract the iron filings (warm water works best, and stir for 20 minuutes - placing
the soupy cereal into a Ziploc bag makes this experiment less messy). Try using a
cereal with 100% RDI (Recommended Daily Intake, RDI, replaces the U.S. RDA,
Recommended Daily Allowances) for the best results.
Putting magnets to work
The force from a magnetic field can be used to do work (move things), and magnets are important components
in electrical systems, motors, computers, speakers, etc. Observe how we can use a magnet to push a grape or
move a paper clip, or attach a good report card to the refrigerator. Studying science makes you smart!
for online resources, please visit:
www.coolmagnetman.com
www.stevespanglerscience.com