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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. 30