Download Reading Comprehension Worksheet - 9th Grade

Science Reading Comprehension Worksheet Magnetism &
Electricity
Magnetism and electricity are closely related phenomena. Electric charge is a
fundamental property of matter. Matter is made up of electrons, neutrons, and protons.
Electrons have a negative electric charge, while protons have a positive electric
charge; neutrons have no electric charge. These tiny particles are the building blocks of
atoms. An atom has a net positive electric charge when it loses one of its electrons, and
a net negative electric charge when it gains an extra electron. On the other hand,
magnetic charges do not exist - Magnetic fields are generated solely by moving
electric charges.
An example of the relationship between electricity and magnetism is the motor. In a
motor, a voltage is applied across the terminals of a coil of wire. The voltage causes the
electrons in the wire to move, which in turn generates a current. This current results in a
magnetic field, which interacts with permanent magnets attached to the core of the
motor, causing it to move.
Perhaps the most significant relationship between electricity and magnetism is light,
which is known to physicists as an electromagnetic wave. Light waves are oscillating
patterns of electric and magnetic fields, propagating through space at the speed of
light (3x108 meters/second).
Electric and Magnetic phenomena are intricately described by a collection of physical
laws, known as Maxwell's equations. Fully understanding these complex equations
require a thorough knowledge of calculus and differential equations. For more
information, take a course in electromagnetic theory from your local university.
1. What is an atom made up of?
2. What is a magnetic field?
3. In most cases, does electricity create magnets or do magnets create electricity? Explain.
4. When some on say "The Speed of Light", what are they referring to?
Magnetism & Electricity Vocabulary Quiz
Directions: Match each definition with the correct term.
1. magnet
a rock that possesses magnetic properties and attracts iron;
magnetite.
2. current
a physical phenomenon caused by the movement of certain
charged particles such as electrons, esp. between points having
different electrical charges, and seen in naturally occurring
phenomena such as lightning and magnetic attraction and repulsion.
3. electricity
to drive away or force backwards.
4. attract
an instrument for determining direction, esp. one with a horizontal
magnetic needle that rotates freely until it points to the magnetic
north.
5. battery
active power, energy, or physical strength.
6. electromagnet
an object that attracts iron and some other materials by virtue of a
natural or induced force field surrounding it.
7. circuit
a device that generates electricity by means of chemical reactions.
8. lodestone
(loadstone)
the flow of electricity in a conductor.
9. repel
a negatively charged particle, considered a fundamental unit of
matter, that exists independently or outside the nucleus of an atom.
10. electron
a magnet in which an iron or steel core is magnetized by the electric
current in the coil of insulated wire wound around it.
11. force
to cause to come near, as by some special quality or action.
12. compass
an Arrangement of electronic elements, including conductors,
resistors, and the like, through which electric current moves.
Magnetic Attraction!
An object that attracts metals, especially iron, is called a magnet. The area near the
magnet where it has enough power to attract things is called its magnetic field. The
farther away from the magnet an item is, the weaker the magnetic field is. When it is
weak, it is less likely an object will become attracted to the magnet. Magnets can be
either permanent or temporary. A permanent magnet stays magnetized for a long time.
A temporary magnet loses its magnetism after only a short time. You can even turn
something made out of iron into a temporary magnet by rubbing it against a permanent
magnet. The more you rub, the stronger your temporary magnet gets. However, the
effects will wear off over time. The two ends of the magnets are called magnetic poles.
The poles are found at the ends of bar magnets and the tips of the horseshoe magnets.
They are the strongest parts of the magnet. Each magnet has a north pole and a south
pole. Opposite poles attract, or pull toward each other. Poles that are the same repel, or
push away from each other. A north pole and a south pole will pull toward each other.
Two north poles will push away from each other. The same happens with two south poles.
When you hold magnets, you can actually feel the push and pull effects of magnetism. A
special kind of temporary magnet uses electricity to create a magnetic field. It is called
an electromagnet. An electromagnet can be an extremely strong magnet. However, it
only acts like a magnet when it has electricity. A stronger electrical current will produce
a stronger magnet. Unlike other magnets, an electromagnet can be controlled by a
switch. When the switch turns the electrical current off the electromagnet loses its
magnetism. Whatever the electromagnet was holding drops to the ground. We use this
technology to operate large cranes that lift heavy metal objects, such as cars.
Electromagnets are also used to make motors run in small appliances. Combining regular
magnets and electromagnets makes it possible for electrical energy to be turned into
energy of motion.
Answer the following questions based on the reading passage. Don’t forget to go back
to the passage whenever necessary
1) Explain the difference between a temporary magnet and a permanent magnet.
2) Would two north poles attract each other or push away from each other?
3) What is different about an electromagnet?
4) What do we use electromagnets for?
5) What does attract mean when speaking about magnets?