Energy Transfer Unit – Magnetism Notes Attract- To attract means to pull toward one another. Iron and steel objects are attracted to magnets. Magnet- A magnet is a material that has the ability to attract iron, steel, or an iron alloy. Repel- To repel means to push away from one another. Investigation 9 – What materials are attracted to a magnet? In this investigation the iron nail, paper clip, washer, and safety pin were attracted to the magnet. The plastic spoon, paper, styrofoam peanut, and rubber band were not attracted to the magnet. The materials attracted to the magnet were all made of metal. The objects not attracted to the magnet were not made of metal. Magnetic- A magnetic material is a substance that is attracted to a magnet and can act like a magnet. Magnetically attract- If two objects magnetically attract to each other, they are pulled toward each other. Iron and steel objects are magnetically attracted to magnets. When two unlike poles of magnets are placed near each other, they are magnetically attracted. Magnetically repel- If two objects magnetically repel each other, they are pushed away from each. When two like poles of magnets are placed near each other, they are magnetically repelled. Investigation 10 – What metals are attracted to a magnet? Not all metals are attracted to a magnet. The data shows that some materials made of metal were not attracted to the magnet. Magnets attract objects made of iron, cobalt, and nickel. Aluminum, brass, and copper are not attracted to a magnet. What effect does distance between a magnet and magnetic material have on attraction? The magnetic field expands beyond the actual magnet. Some magnets are stronger than others and will attract objects from a greater distance. Will a magnet continue to attract objects with a barrier placed between them? The paper clip was attracted to the magnet through the thin material and not through the thick block. The paper clip moved toward the magnet through the cloth, paper, and cardboard. There was no magnetic attraction through the wooden block. Iron Fillings – Iron fillings are shaved bits of iron metal. Iron fillings are used to demonstrate magnetic field, magnetic poles, and lines of force. Lines of force – Lines of force are the invisible lines that make up a magnetic field. The lines of force are closer together and stronger at the poles of a magnet. Magnetic Field – A magnetic field is the area of attraction and repulsion that surrounds a magnet. Magnetic Pole – A magnetic pole is a place on a magnet where the magnetic effect is the strongest. The two ends of a bar magnet are its poles. Investigation 11 – How can you tell that magnets are strongest at the poles? From the data collected the ends of a bar magnet appear stronger because they attracted the greatest number of paper clips. How can you tell a magnet has two poles? You can tell a magnet has two poles because more paper clips are attracted to both ends of the magnet than anywhere else on the magnet. Investigation 12 – What is observed when like poles of magnets are placed near each other? Like poles (north pole to north pole or south pole and south pole) magnetically repel or push away from each other. What is observed when unlike poles of magnets are placed near each other? Unlike or opposite poles (north pole and south pole) are magnetically attracted to each other. Compass – A compass is a tool that uses a magnetic needle to indicate direction on the Earth’s surface by pointing toward the north. Investigation 13 – Which way is north? If you suspend a bar magnet by fishing line the magnet’s north seeking pole will face north. The colored end of a compass needle points north even when if the dial of the compass is not turned toward north. The compass needle continues to point north if you turn the compass. The compass needle is like a free swinging magnet because they both have poles. The north seeking pole of the compass needle and the north seeking pole of the magnet both point to the north. Electromagnet – An electro magnet is produced when electricity flows through a coil of wire wrapped around an iron bar. It acts like a magnet. Investigation 14 – How can electricity be used to produce heat and a magnetic field? An electromagnet can be made by wrapping a wire many times around an iron nail. The nail is then connected to a battery. As long as the wire is connected to the battery the nail is able to pick up paper clips. If you disconnect the wire from one end of the battery the paper clips fall off. The paper clips are no longer attracted to the nail because the electrical circuit from the battery was open or incomplete. The battery and the wire coiled around the iron nail shows how electricity can produce magnetism.