Electricity Lesson 1 How Are Electricity and Magnetism Related? Electricity Recall that atoms contain charged particles. A proton has a p_____________________ charge. An electron has a n_____________________ charge. An atom can have m_________ electrons than protons. This gives the atom a n________________ charge. An atom with more protons than electrons has a p_____________ charge. Atoms with o________________ charges attract each other. In an atom, electrons move around o________________ the nucleus. In some elements, electrons can also move from one atom to another. This m________________ of e________________ p________________ e________________. Electricity(DEFINE):___________________________________________________ __________________________________________________________________ Lamps change electricity into l________________ energy. Electricity changes to motion, or m________________ energy. Electricity can also change to h________________ energy. What do a doorbell and a radio have in common? They both use electricity to produce s________________ energy. MAIN IDEA AND DETAILS: What are four kinds of energy that electricity can be changed into? ________________________________ ________________________________ ________________________________ ________________________________ Electricity and Magnetism An electromagnet:____________________________________________________ _________________________________________________________________. When electricity flows through a wire, the wire has a m______________ f______________ around it. A single wire doesn’t have a strong magnetic field. Winding the wire into a c_____________ makes the magnetic field stronger. Each t________________ of the wire makes the field s________________. Electromagnets are useful because they can be turned on and off. You have seen that e________________ can produce m________________. This also works the other way around—a m________________ can produce e________________. MAIN IDEA AND DETAILS: What are some ways in which electromagnets are used? __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ Electric Motors You know that e________________ can be changed to m________________ e________________. The motion of an electric device is produced by an e________________ m________________. The electric motor is the opposite of a generator that produces electricity in an energy station. A motor contains a c________________ of w________________ that can s________________ inside the m________________ f________________ of a permanent magnet. When the motor is switched on, electricity produces a magnetic field in the coil of wire. The c________________ becomes an e________________. The poles of this electromagnet are attracted and repelled by the poles of the permanent magnet. This causes the electromagnet to spin. The motion of the spinning coil can turn the blades of the blender or the fan. MAIN IDEA AND DETAILS: What are the two main parts of a motor? _________________________________ _________________________________ Lesson 2 What Are Static and Current Electricity? Static Electricity Most objects have no charge. The atoms making up the matter are n______________________. They have equal numbers of protons and electrons. But when one object rubs against another, electrons move from atoms of one object to atoms of the other object. The numbers of protons and electrons in the atoms are no longer equal. The objects become either p_____________________ or n______________________ charged. The buildup of charges on an object is called s______________________ e______________________. O______________________ charges a______________________ each other. When objects with opposite charges get close, e______________________ sometimes j________________ from the n______________________ object to the p______________________ object. This evens out the charges, and the objects become neutral. CAUSE AND EFFECT What causes an object to build up a static charge? __________________________________________________________________ __________________________________________________________________ Current Electricity For electricity to be a useful source of energy, it must be a s_______________ f____________ of charges. If electrons have a path to follow, they will move in a steady flow instead of building up a static charge. This f____________ of e___________________ is called an e_________________ c__________________ . Electricity that flows in this way is a kind of kinetic energy called current electricity. To keep the charges flowing, a c__________________ supply of e________________ is needed. Electrical pressure forces current through the wires, giving the electrons energy. This e______________________ p______________________ is measured in v_________________. The rate at which electric current flows is measured in a_________. The combination of volts and amps can be dangerous, which is why many objects that use electricity have warning labels. The amount of electrical energy a device uses each second is measured in w_____________. A label on a hair dryer, light bulb, or clock shows how many watts it uses. One kilowatt is equal to 1,000 watts. CAUSE AND EFFECT What causes an electric current to keep moving? __________________________________________________________________ __________________________________________________________________ Conductors and Insulators Electricity moves more e______________ through some kinds of matter than others. A material through which electricity moves well is a c______________ . Most metals are conductors. The electrons of m_____________ are held loosely by the atoms. This makes it e____________ for the electrons to move between atoms, causing current to flow. P______________________ doesn’t conduct electricity well. Its electrons are n__________ free to move between atoms. A material that conducts electricity p______________________ is an i______________________ . Wood, glass, and rubber are also insulators. Insulators are important because they p______________________ you from the electric current in the wire. If the layer of plastic on a wire peels off or cracks, the w______________ s_______________ be r_______________. If you touch a bare wire that is conducting current, the current will flow through you and c______________________ h____________ you. Also, wires get warm when they carry electricity. A bare wire that touches paper or cloth could start a fire. CAUSE AND EFFECT What causes a metal to be a good conductor? __________________________________________________________________ __________________________________________________________________ Lesson 3: What are Electric Circuits? Series Circuits The wires give the e__________________ a path to follow. The path an electric current follows is called an electric circuit. An electric circuit needs t______ things for current to flow. First, it needs a s__________________ of current, or electrons. Second, the circuit has to be c__________________. If there is a b__________________ in the circuit, the current won’t flow. A battery, wires, and light bulbs can form a complete circuit. A s__________________ controls the flow of current by o__________________ and c__________________ the circuit. When the switch is on, the circuit is complete. The light comes on. When you turn the switch off, a piece of metal inside the switch moves. This b__________________ the flow of current, and the light goes out. In a series circuit, the current has only o__________________ path to follow. The parts are connected one after the other in a s__________________ l__________________. Removing any part of the circuit breaks the circuit, and current s__________________ flowing. MAIN IDEA AND DETAILS What two things are needed in order for current to flow in a circuit? __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Parallel Circuits Instead of giving the current only one path, you can make a path for e__________________ d__________________ in the circuit. A circuit that has m__________________ t__________________ one path for current to follow is called a p__________________ c__________________. In a parallel circuit, if one device is turned o______ or r________________, current stops flowing along the loop f_______ t__________ d_________________. But current c__________________ to f________________ through the rest of the circuit. The other devices don’t stop working. This makes a parallel circuit m____________ p_________________ to use than a series circuit. A parallel circuit has another advantage over a series circuit. You can connect m_______________ d________________ in a parallel circuit. If you connect too many light bulbs in a series circuit, they all become dimmer. That’s why old signs wired in series circuits didn’t have many bulbs. But in a parallel circuit, adding more bulbs doesn’t change how bright they are. MAIN IDEA AND DETAILS What are two advantages that parallel circuits have over series circuits? ____________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Drawing Circuits You have learned that d__________________ that use e__________________ have c__________________ inside them. Engineers design these circuits. Some circuits, such as those in a blender or a lamp, are simple. Some, such as those in a car or an airplane, are m__________________ c__________________. When engineers work on a new design, they don’t begin by connecting a lot of wires. Instead, they draw diagrams of the circuits they will use. Circuit diagrams use s__________________ to show the p__________________ of a c__________________. Each part of a circuit has a d__________________ s__________________. A diagram of the series circuit you built in the Investigate would have symbols for the b__________________, the w__________________, and the t__________________ lights. These symbols would be connected in a s__________________ l__________________. MAIN IDEA AND DETAILS What do you see on a circuit diagram? __________________________________________________________________ __________________________________________________________________ __________________________________________________________________