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Transcript
Magnets Lesson 1
Can you think of a time when you moved something
without touching it? It sounds impossible, but with
magnets it happens. Magnetic marbles and other magnetic
toys move each other or stick together.
You can’t exactly see what happens to make the
magnets stick together, but you can see the effects.
Have you ever wondered how the pull gets from one
magnet to another or to the refrigerator? The magnets
you use most are probably the ones that hold up your
papers on your refrigerator.
Like static electricity, magnets exert a force, and
you can observe how this force interacts with objects
around you.
1
Just the Facts
•
•
•
•
•
•
•
•
•
•
•
Ancient Greeks and Chinese knew about magnetism over 2,000 years ago.
They hung thin pieces of magnetite so it could swing freely from a thread. The
hanging stone made a simple direction finder.
Magnetite became known as lodestones or “leading stone.”
Objects attracted by a magnet contain iron or steel.
Magnets have two unlike poles. They are given the names north and south.
Unlike poles attract and like poles repel.
The iron’s magnetism comes from the electrons.
Magnetic force can pass through other solid objects.
The earth is a huge magnet.
There are two ways to magnetize an iron nail (a temporary magnet):
1) Stroke the nail with a magnet. Each stroke should be in the same direction
and with the same pole of the magnet.
2) Place the flat head of a nail on one end of a magnet for a few minutes.
The reason a nail can become a temporary magnet is due to a change in the nail
that we can not see. The nail is made up of tiny particles that we can not see.
These particles are not lined up in any special way. But, when we stroke the nail
with the magnet, the tiny particles line up all in a row.
Non-magnetized molecules are not
arranged in any particular order.
•
Magnetized molecules are arranged
in an orderly manner.
But, the particles of the nail do not stay lined up for a long time. The nail then
becomes demagnetized.
2
Making a Magnet Experiment
A very long time ago, a mineral was found that had a special property. When it
came in contact with certain metals, the mineral and the metals would stick together.
At first, people thought this property was some kind of magic.
What people thought was a magic stone was really a magnet. A magnet is a piece
of material or a device that attracts iron-containing materials and some other metals. A
natural magnet is called a lodestone. Lodestones were the first magnets known to
people.
A lodestone is not the only kind of magnet. Certain metals can be magnetized, or
made into magnets. Iron, nickel, and cobalt can be magnetized. Most magnets are made
of a mixture of these metals. Suppose you want to magnetize an iron nail. You can use a
magnet to make a magnet. One way is to place the nail in contact with a magnet. After
a while, the nail will become magnetized. Another way to magnetize the nail is to stroke
the nail with the magnet. Each stroke must be made slowly in one direction. After many
strokes, the nail will become magnetized.
Materials
Bar magnet, nail, paper clip, staples
Procedure
1. Rub the nail 50 times in one direction with the magnet. Hold as much of the nail
(not just the tip) against the magnet as possible.
2. Touch the nail to the paper clip, and the staples.
Observations: ______________________________________________________
__________________________________________________________________
__________________________________________________________________
Conclusions: ________________________________________________________
__________________________________________________________________
__________________________________________________________________
3
How Magnets Behave Experiment
The places where the pull of a magnet is strongest are called magnetic poles.
There are two kinds of magnetic poles, north (N) and south (S). The same poles (N to N
or S to S) push away (repel) from each other, while opposite poles (N to S or S to N)
pull toward each other (attract). Like magnetic poles of a magnet repel each other.
Unlike magnetic poles attract.
Magnets can be different sizes and shapes. They can be made of different
materials. But, all magnets behave alike. Materials not attracted by magnets are called
non-magnetic. Such materials cannot be magnetized. Only magnetic materials can be
magnetized. The most common magnetic materials are iron and steel. Other, less
common magnetic materials are cobalt and nickel.
Magnetic forces cause magnets to attract or repel other magnets. Magnets can
also attract certain other objects. Objects that are attracted by a magnet are called
magnetic objects. The forces of attraction or repulsion are not the same throughout
the magnet. Magnetic forces are greatest at the poles of a magnet.
Materials
two bar magnets
Procedure
1. Set up each magnet according to the directions below. Then write your
observation (attracts or repels).
A.
B.
C.
D.
North to South
North to North
South to North
South to South
Observation:
Observation:
Observation:
Observation:
________________________________
________________________________
________________________________
________________________________
Conclusion
1. Describe the characteristics of unlike magnetic poles.
_____________________________________________________________
_____________________________________________________________
2. Describe the characteristics of like magnetic poles.
_____________________________________________________________
_____________________________________________________________
4
What Will a Magnet Attract
Directions: Predict which object will be attracted by the magnet by writing yes or
no under the prediction section. After all of the predictions have been completed,
test each object using a magnet.
Material
nail
Prediction
Actual Results
marble
paper clip
rubber band
pins
brass fasteners
penny
nickel
eraser
crayon
scissors
pencil
paper
Conclusion
1. From your observations, it should be clear that certain materials are attracted by
a magnet. Underline those materials which are attracted by a magnet.
copper
rubber
iron
paper
wood
steel
2. Materials attracted by a magnet are called ______________________.
3. Materials not attracted by a magnet are called _____________________.
4. Write down two other objects in the classroom that are nonmagnetic.
________________________
______________________
5. Write a sentence about what you learned from this experiment.
_____________________________________________________________
5
Will a Magnet Work in Water?
Materials
magnet on a string, glass jar, metal objects, non-metal objects, water
Procedure
1. Tie string through the magnet. Place metal and non-metal objects in the jar and
add water to fill the jar 2/3 full.
Predict: If you put the magnet into the water, what will you observe?
_______________________________________________________________
_______________________________________________________________
Try it!
Write your observations. What materials did the magnet attract? List them.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
Conclusion
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
6
Do the experiment described below and discover the invisible magnetic force. Use a
partner to help you complete all the steps.
Start with: 5 thick books (a 10” stack)
bar magnet
15” piece of string
large paper clip
12” ruler
collection of the following test items:
small piece of paper,
bottle opener
large nail
small piece of cardboard
small piece of plastic wrap
tin can lid
small piece of thin glass
steel tacks
small piece of thick cloth
scissors
Step 1: Make a stack of books 10 inches
high. Place the magnet on top of the
stack of books so that one pole
extends over the edge of the stack
Step 2: Tie the 15 – inch piece of string
to a large paper clip.
Step 3: Push a thumbtack halfway into the
ruler. Then wind the string with
the paper clip twice around the
thumbtack. Leave about nine inches
between the paper clip and the ruler
Step 4: While one student holds the paper
clip one-fourth of an inch away from
the magnet, another student pulls
the loose end of the string tightly
7
around the thumbtack. Then push
the thumbtack into the ruler to
secure the string. The student
holding the paper clip may let go
and the paper clip should remain
suspended the by magnetic force
of the bar magnet.
Step 5: Without touching the paper
clip, pass the materials from the
collection of testing items
between the magnet and the
paper clip. Record on the chart
on the next page which items
made the paper clip fall and which
ones did not. (Each time the
paper clip calls, carefully suspend
it again as shown in Step 4.)
1. What is similar about all the items that made the paper clip fall?
_____________________________________________________________
_____________________________________________________________
2. What is similar about all the items that did not make the paper clip fall?
_____________________________________________________________
_____________________________________________________________
3. What conclusions can you make from this experiment?
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
8
The area around a magnet where the magnetic force acts is called the magnetic
field. The magnetic field cannot be seen. It makes no noise. It has no odor or taste.
You cannot touch it.
You can feel the effects of a magnetic field. You can feel the push or pull when
you bring tow magnets together. You can feel the magnetic field when you bring an
object, such as a paper clip, close to a magnet. As you move the paper clip closer to the
magnet, you reach a point where you can feel the magnet pulling the clip.
Although you cannot see a magnetic field, you can see its effect. When iron
filings are placed near a magnet, they form a pattern. This pattern shows the shape of
the magnetic field. The pattern seems to end at the surface of the magnet. You cannot
see it, but the magnetic field goes through the magnet also. The size of the magnetic
field depends upon the strength and size of the magnet.
9
Location of a Magnetic Field Demonstration
Facts to Know
Unlike poles attract each other. Like poles repel each other. A magnetic field is
formed by the magnetism that radiates from a magnet.
Procedure
1. You will need two pieces of string and two magnets. Tie a piece of strong to the
center of each magnet. Hold the string with the magnets next to each other.
Twirl the magnets.
Observation
Do the magnets always stop with the same sides touching each other?
_______________________________________________________________
Can you get the north pole of one magnet to dangle right next to the north pole of
the other magnet?
_______________________________________________________________
2. Place a bar magnet under a sheet of paper and sprinkle with iron filings.
• Do not slide the paper away from the magnet. Iron filings will attach to
the magnet and be very difficult to remove.
• Do not touch the iron filings with your fingers!
Observation:
Draw your observations below and label
Conclusions
1. What do you discover when we dropped the iron filings on the magnet over the paper?
__________________________________________________________________
2. The iron filings show the greatest force _________________________________.
10
Directions: Below are drawings of bar magnets. On each, draw the lines of magnetic
force that show the location of the magnetic field.
1.
N
S
2.
S
N
N
S
3.
S
N
S
N
4. What do the letters “N” and “S” stand for on the magnets?
__________________________________________________________________
__________________________________________________________________
5. How could you test each of the predictions you have made?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
11
How Are Magnets Made?
There are three different kinds of magnets: natural, temporary, and permanent.
Each kind is made in a different way.
Natural magnets are rocks with a lot of iron in them. Magnetite is an example of
rock that is naturally magnetic. Natural magnets are magnetic when they are found in
the ground. No one has to do anything to them, because they are already magnets.
Temporary magnets are called that because they are weak and last only a short
time. They are made from pure (soft) iron. One way to make a temporary magnet is to
stroke a soft iron object (like a nail) with a magnet.
Permanent magnets are made from “hard” iron, which is iron plus some other
special materials. Steel is a hard iron, so it makes good permanent magnets. If we
strong steel scissors they will be magnetized. There are called permanent magnets
because they are strong and because they hold their magnetism for a long time.
A ceramic magnet is a special kind of permanent magnet. The ring magnets we use
in school are ceramic magnets. They are made from a form of iron called strontium
ferrite. This powder is pressed into molds. Then it is put into a very hot oven where it
is heated to 2,250 degrees Fahrenheit. As these future magnets cool, they shrink
slightly. The flat sides of ring magnets become their poles.
Uses of Magnets
There may be a number of ways magnets are used in your home. Perhaps a magnet
holds the refrigerator door shut. Some cabinet doors are held shut with magnets also.
You may use magnets to attach notes, lists, or drawings to refrigerator doors or
magnetic bulletin boards.
Bar magnets are used in compasses. A compass is an object used by travelers to
determine direction. The needle in a compass is positioned so it can turn freely. The
needle is usually a magnet. The needle always points north. The north pole of a magnet
seeks the North Pole of the Earth. By knowing where north is, a traveler is able to find
other directions.
Bar magnets can be bent into a horseshoe shape. Horseshoe magnets are used
where a strong magnetic field is needed in a small space. These magnets are used in the
motors of some toy cars.
Large industries use magnets. Magnets can be used to separate valuable metals
from other matter. In other industries, magnets are used to pick up small pieces of
metal that rub off machinery. This helps keep the machinery clean. Clean machinery
breaks down less often. In the food and chemical industries, magnets keep metal
particles from mixing with the products. Magnets have been used from searching for
underwater treasure to removing a steel splinter from an injured person’s eye.
12
Magnets come in many shapes and sizes, but the cow magnet was invented to solve
a very serious problem of dairy farmers. To understand how cow magnets help, it is
necessary to know how a cow’s stomach works.
As you might guess, a cow has a very large stomach. In an adult cow it can hold
about 280 liters (over 60 gallons) of food. The stomach is divided into four
compartments: the rumen, the reticulum, the omasum, and the abomasums.
The muscles in the walls of the rumen and reticulum mix and moisten the food.
Then it is passed back up into the mouth, where the cow chews it thoroughly. We say
the cow is “chewing her cud.” Then the food is swallowed a second time. This time it
passes through all four sections of the stomach and on to the rest of the digestive
system.
When we start to eat food with a seed or a piece of bone in it, we usually feel it
in our mouths before we swallow it. Cows, on the other hand, swallow their food so
quickly the first time that they do not sort out the small bits of hay wire and other
scrap that gets into their food. As a result, they swallow many of these bits of wire.
If the wire stays with the food, there is no problem, but unfortunately, the wire
often becomes lodged in the honeycomb-like hexagonal cells of the mucous membrane in
the cow’s reticulum or second stomach. The motion of the cow causes some of the wires
to go through the walls of the cow’s digestive tract and sometimes even into its heart.
Veterinarians use a special tube to put a cow magnet in the back of the cow’s
mouth. The cow swallows the magnet easily because it is long, narrow, and round,
something like a thick, smooth, heavy crayon. Since the magnet is heavy, it sinks to the
bottom of the rumen. As wire bits go into the rumen, they stick to the magnet instead
of the stomach lining. One small cow magnet can help a cow for her whole life.
13
Magnets and Compasses
Materials
compass, bar magnet
Procedure
1. Place a compass on your desk and bring a bar magnet next to the compass as shown.
Complete the drawing how the needle is positioned.
2. Now place the bar magnet as shown. Complete the drawing.
3. Move the magnet and complete the drawing.
4. Is the pointer of the compass a north seeking pole or a south seeking pole?
___________________________________________________
___________________________________________________
___________________________________________________
5. Predict what will happen in the drawing below. _____________________________
Check your answer with a magnet and compass and complete the drawing.
14
15
16
Making Inferences
Look at the illustrations below. Use what you observe to help you answer the questions.
Three magnets and a compass were placed under a piece of glass. Iron filings were
gently sprinkled on the glass, revealing the magnetic fields below.
1. What is around the magnets? _________________________________________
2. Where on the magnets is the magnetic force the strongest? __________________
3. The arrow end of the compass is its north pole. Is the box labeled A a north or
south pole? Explain how you found your answer.
__________________________________________________________________
__________________________________________________________________
4. Identify the poles labeled B, C, D, and E as either north or south poles.
B _______
C _______
D _______
E _______
5. Explain how you identified the poles.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
17
Magnets should not be held near these things:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
TV
VCR player
DVD player
microwave
microw
ave oven
computer
radio
loudspeakers
credit cards
computer disks
cassette tapes
tape recorders
telephones
answering machines
video tapes
How Do Magnets Lose Power?
Magnetic materials can be magnetized or made into magnets. They cal also be
demagnetized and lose their power. All magnets become weaker gradually over time.
This is called aging. There are other ways they become weaker, either suddenly or
gradually.
Hitting or dropping magnets can strengthen or weaken them, depending on where
it happens. In a STRONG magnetic field (near a strong magnet, for example), tapping
iron or steel can help to align the domains (at the poles) and magnetize them. On the
other hand, if magnets are dropped or hit in a WEAK magnetic field (away from
magnets), they will lose some of their magnetism.
To keep magnets strong, we should try not to drop them or hit them against
anything. To keep magnets strong, it is important to store them properly. Always place
them so that their opposite poles are together. They should attract one another, not
repel. Each horseshoe magnet should be stored with a keeper, a piece of soft (pure)
iron across its ends or poles.
If we are careful not to drop or hit our magnets, they will stay strong for a long
time.
18
Making It Stick Review
19
Review Questions
1. What are two properties of a magnet?
__________________________________________________________________
__________________________________________________________________
2. What behavior of magnetic poles is always the same?
__________________________________________________________________
__________________________________________________________________
3. Where is a magnet’s force strongest?
__________________________________________________________________
__________________________________________________________________
4. How can you see the effects of a magnetic field?
__________________________________________________________________
__________________________________________________________________
5. Describe two ways an object can be magnetized.
__________________________________________________________________
__________________________________________________________________
6. What are two household uses of magnets?
__________________________________________________________________
__________________________________________________________________
7. How can you feel the effects of a magnetic field?
__________________________________________________________________
__________________________________________________________________
8. What is a lodestone?
__________________________________________________________________
__________________________________________________________________
20
Problem Solving
Explain what you would do to try to solve each of the problems listed below.
1. A steel paper clip was dropped into a glass of water. How can you remove the clip
from the glass without spilling out the water, getting your hands wet, or putting
any tool or object into the water?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
2. How could you tell which of an assortment of rocks were lodestones, or natural
magnets? Describe any tests you would perform.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
3. A jar on a desk contained two different kinds of plastic paper clips. One kind of
plastic paper clip was not attracted to a magnet while the other kind was
attracted to the magnet. How can you explain this? How would you find out the
cause for the attraction?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
4. How could you turn an ordinary screwdriver into a magnetic screwdriver capable
of holding a screw at its tip?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
21
Magnets Lesson 1: Making It Stick
Study Guide
Magnet: a piece of material or device that attracts iron containing materials
and some other metals.
Magnetic Poles: places where the pull of the magnet is the strongest
Magnetic Field: refers to the way magnets exert force on iron-containing
objects, other magnets, and some special materials
Lodestones: “leading stone,” a natural, permanent magnet that was used to
find directions
You can make a temporary magnet by stroking a nail with a magnet in one
direction. These line up the particles in one direction and allow it to pickup
lightweight objects for a short amount of time.
A magnet will attract objects made of metal, iron, and steel.
A magnet will not attract rubber, plastic, wood, paper, etc.
A magnet has two poles a north and a south pole. They are called the magnetic
poles.
Two like poles (N to N, S to S) will repel away from each other. Two unlike
poles (N to S, S to N) will attract each other. This is different from static
electricity because once you have a magnet, you don’t have to charge it each
time you use it.
The pushing and pulling behavior of a magnet is called magnetic force. The
magnetic force is strongest at the poles.
When we did our experiment with the magnets and iron filings, we discovered
the magnetic field, the area of force around the magnet.
The north pole of a magnet seeks the North Pole of the Earth.
Magnets are used on cabinet doors, refrigerator doors, electric can openers,
compasses, medical magnets, decorations, etc.
22
Magnets Lesson 2
Magnets from Electricity
Electricity can also be used to magnetize metal. When
electricity passes through a wire, a weak magnetic field is
formed around the wire. The magnetic field can be used to
magnetize metal. Look at the picture. A wire has been wrapped around a nail. If you
pass electricity through the wire, the nail becomes magnetized. When the current is
stopped, the nail is no longer a magnet. A temporary magnet made by using electricity is
called an electromagnet.
How We Use Electromagnets
Electromagnets come in all sizes, from little ones that
make doorbells ring by pulling a striker rapidly forward, to
enormous magnets that stick to and pick up entire cars. Some
soda cans are made of steel and some of aluminum. Recycling
centers want to separate the aluminum cans from the steel
ones. Since all steel has iron in it, electromagnets are used to
pull the steel cans out from among the aluminum ones.
Electromagnets control what you hear and what you see, too. In a cassette
player, the shiny rounded metal parts with black parts on the inside are magnets. You
can’t see inside a VCR easily because of the way it’s built, but it has magnets, too. TV
picture tubes and stereo speakers contain powerful electromagnets. Some
electromagnets are used in junkyards to move large cars or trucks.
Just the Facts
•
•
•
•
•
•
Light is a form of an electromagnetic wave.
Electricity can be used to make powerful magnets called electromagnets.
Electromagnetic induction allows for the creation of huge electrical generators.
Electromagnets can be switched on and off. The core of the electromagnet can
be iron or steel – this makes the magnet stronger.
Electromagnets have coils of electric current – the number of coils and voltage
control the strength. The strength of an electromagnet may be increased by
adding more electrical current to it.
Without electromagnets, there would be no hair dryers, TV’s, or computers.
23
Whenever an electric current goes through a wire, a magnetic field is created
around the wire. Electricity and magnetism are related; an electric current produces a
magnetic field, and a change in a magnet in a magnetic field can produce an electric
current. When current goes through a coiled wire, the magnetic field is strengthened
because each coil acts like a separate magnet.
The strength of an electromagnet can be increased in several ways. The number
of coils can be increased. The voltage of the current going through the wire can be
increased. Using a metal core, such as a nail or a bolt, will also increase the strength of
the electromagnet. The magnetic field produced by the current in the coils induces a
magnetic field in the iron core.
Electromagnets are an integral part of many common devices such as telephones,
electric motors, generators, televisions, and door bells.
Electromagnets are demagnetized each time the electric power is turned off.
This is useful because we want to control them. When we tell an electromagnet to
magnetize, it will lift heavy objects made of magnetic material. When we tell it to
demagnetize, it will drop or let go of the objects. Electromagnets are made so that
they gain or lose magnetic power when we press the right buttons. When they lose
power, they are doing exactly what we want them to do.
An electromagnet can sort one material from another. For example, if you are
trying to separate materials that that contains iron or steel from a material that does
not contain iron or steel. This works because the electromagnet will only pick up the
material that has the iron or steel and leave the other material alone.
How to Make an Electromagnet
To make an electromagnet you would need some insulated wire, something to use
as the core (a nail) and a source of electric current (an electric cell – battery). The wire
needs to be wrapped around the iron core. Then connect the ends of the wire to the
electric power source. When current is flowing through the wire, the coil and the iron
core will become an electromagnet.
You could increase the strength of an electromagnet by increasing the number of
loops of wire around the iron core. Another way to increase the strength is to increase
the amount of current in the circuit. For example, if you used one electrical cell to
make the magnet, use two cells.
24
Make An Electromagnet Demonstration
Materials
nail, insulated wire, battery, staples,
paper clips
Procedure
To make your electromagnet:
1) Wind the wire tightly around the nail,
leaving about 10 cm free at both ends.
2) Remove the insulation at both ends of
the wire.
3) Attach the wire to both ends of the
battery.
4) Test the nail electromagnet by picking
up the staples and paper clips with the nail. Record your observations.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
5) Disconnect the battery. Record your observations.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
Conclusion
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
25
Current Attractions Review
26
1. What can a magnet do?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
2. How many poles does a magnet have? Name them.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
3. Explain how you could make a magnet yourself.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
4. What part of a magnet has the most magnetic strength?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
5. What would happen if you put two magnets together?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
27
6. Where does the needle on a magnetic compass point?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
7. What would happen if you put a paper clip near a magnet?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
8. Describe how you could make an electromagnet.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
9. What are two ways that you could increase the strength of the electromagnet you
just described?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
10. How could electromagnets be used to sort one type of material from another?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
28
Final Exam Study Guide for Electricity & Magnetism
Circuit- a path that electricity can move through.
Lightning- electricity in the clouds
Lodestone-“Leading Stone”-a natural, permanent magnet that contains magnetite.
Two objects that pull toward each other are said to have different charges.
Nucleus - the part of the atom that contains the protons and neutrons.
Cell - another name for a battery.
Parallel Circuit - a circuit where if one bulb goes out the other bulbs stay lit.
Grounding - the transfer of electrical charges to the ground
Insulator - a material that doesn’t allow electric to flow trough it easily.
Switch - a device that opens & loses circuits without unscrewing the light bulbs or
disconnecting the wires.
Poles -the ends of a magnet. There is a north & South Pole.
The tiny part of an atom that has a negative charge is called the electron.
Atom - the smallest piece of an element that can still be identified as an element.
The north pole of a magnet points toward the magnetic north of the Earth.
Resistor -a material that resists the flow of electricity.
Circuit Breaker - keeps excess current from flowing through the wires.
When an object loses some of its electrons it will have positive charge.
Current Electricity -electricity that moves like currents in stream or river.
Series Circuit - a circuit where if on bulb goes out, they all go out.
Conductors - materials that allow electricity to flow them easily.
An example of a resistor in a light bulb is called a filament.
29
Closed circuit -a circuit with no breaks or interruptions.
Magnetic Force -the pushing & pulling behavior of a magnet.
Magnetic Field - the area around a magnet, it is invisible and it surrounds the magnet on
all sides.
A strip of metal that allows excess current to flow through it is called a fuse.
Static electricity - an electrical charge that is on something and doesn’t move.
Electromagnet - a magnet that is produced by an electric current, usually a core of iron
wrapped in conductor.
If two objects repel away from each other, they both have the same charge.
Protons - the tiny part of the atom that has a positive charge.
Open Circuit - a circuit where there are breaks or interruptions.
Know the following diagrams: How to draw them and their labels
An atom and all its parts, also be able to tell what type of charge it is.
A light bulb and label its parts.
A circuit diagram showing either an open or closed circuit and label its parts.
A bar magnet showing its magnetic filed and label its parts.
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