Static Electricity G10 Advanced Physics PDF

# Static Electricity ## Key Concept 5 ## Mastery Programme G10 Advanced Physics Term 1 ## Learning Outcomes * State that there are positive and negative charges. * State that charge is measured in coulombs. * State that positive charges repel other positive charges, negative charges repel other...

# Static Electricity ## Key Concept 5 ## Mastery Programme G10 Advanced Physics Term 1 ## Learning Outcomes * State that there are positive and negative charges. * State that charge is measured in coulombs. * State that positive charges repel other positive charges, negative charges repel other negative charges, but positive charges attract negative charges. * Describe an electric field as a region in which an electric charge experiences a force. * Describe simple experiments to show the production of electrostatic charges by friction and to show the detection of electrostatic charges. * State that the direction of an electric field at a point is the direction of the force on a positive charge at that point. * Explain that charging of solids by friction involves only a transfer of negative charge (electrons). * Describe simple electric field patterns, including the direction of the field: * Around a point charge * Around a charged conducting sphere * Between two oppositely charged parallel conducting plates (end effects will not be examined) * Describe an experiment to distinguish between electrical conductors and insulators * Recall and use a simple electron model to explain the difference between electrical conductors and insulators and give typical examples ## Keywords: | Term | Definition | |---|---| | Static Electricity | Electric charge held by a charged object. | | Coulomb (C) | The SI unit of electric charge. | | Electron Charge | The electric charge of a single electron = $-1.6 \times 10^{-19} C$. | | Proton Charge | The electric charge of a single proton = $1.6 \times 10^{-19} C$.| | Neutral object | An object with equal number of positive and negative charges | | Electric Field | A region around a charged object where any other charged object experiences a force | | Uniform electric field | A field with straight parallel lines which are equally spaced apart. | | Conductor | A material which allows electrons to flow through it. | | Insulator | A material which that does not allow electrons to flow through it. | ## Previous knowledge: In magnetism, we know that opposite poles attract and like poles repel. How does this concept relate to the behavior of charges in static electricity? ## What is Static Electricity? Static electricity is a special type of electrical charge that can build up on the surface of objects when they rub against each other. It's like magic, but it's science! ## Previous knowledge: * The Building Blocks: * Electrons To understand static electricity, we need to meet some tiny particles called electrons. Electrons are like the hidden superheroes of the atomic world. They're part of every atom and can move from one object to another. <start_of_image> Schematic: (A circle representing an atom with a nucleus in the center and the following labels) - Neutrons - Electrons - Protons - Nucleus ## Activity As the slides loop around you have 10 minutes to complete as many of the tasks as possible. Write your answers in these boxes. ### Electric charge | Category | Question | |---|---| | The Unit | | | Charge of proton | | | Charge of electron | | ### Attract or Repel (A circle representing an atom with a nucleus in the center) 1. 2. 3. ### Table | Particle | Charge | Location in the atom | |---|---|---| | Proton | | | | Neutron | | | | Electron | | | ### Fill in the gaps 1. 2. 3. ## Where does static charge come from? All materials are made of atoms, which contain electric charges. Schematic: (A circle representing an atom with a nucleus in the center, and two arrows pointing outwards to the left and right from the nucleus, with the following labels) - Electron (negative charge) - Proton (positive charge) Around the outside of an atom are electrons, which have a negative charge. The nucleus at the center of an atom contains protons, which have a positive charge. An atom has equal amounts of negative and positive charges, which cancel each other out. This means an atom has no overall charge. Electrons do not always stay attached to atoms and can sometimes be removed by rubbing. ## Challenge question: What equation relates current (I), time (t), and charge (Q) in an electrical circuit? Use this equation to answer the following question. The current in an electrical device is 0.21A. Calculate the charge that flows during a 75 s period of time. $Q = It = (0.21 A)(75 s) = 16 C$ ## Electric Charge The charge of a particle can be: * Positive * Negative * Neutral (no charge) Electrons are negatively charged particles, whilst protons are positive, and neutrons are neutral. Therefore, in a neutral atom, the number of electrons is equal to the number of protons. * This is so the equal (but opposite) charges cancel out to make the overall charge of the atom zero * Therefore, an object becomes negatively charged when it gains electrons and positively charged when it loses electrons. The SI unit of charge is Coulombs (C). The charge on each electron is The charge on each proton is ## When two charged particles or objects are close together, they also exert a force on each other. This force could be: * Attractive (the objects get closer together) * Repulsive (the objects move further apart) Whether two objects attract or repel depends on their charge * If the charges are the opposite, they will attract * If the charges are the same, they will repel Schematic: (Two arrows pointing towards each other with + symbols) (Two arrows pointing away from each other with + symbols) Attraction and repulsion between two charged objects are examples of a non-contact force * This is a force that acts on an object without being physically in contact with it | Charge of Object 1 | Charge of Object 2 | Attract or repel? | |---|---|---| | Positive | Positive | Repel | | Positive | Negative | Attract | | Negative | Positive | Attract | | Negative | Negative | Repel | ## Gain or lose electrons Schematic: (A circle representing an atom with three circles around it and a blue circle on the outermost ring) - Hydrogen - Neutral Atom ## An ion has the symbol notation Be 2+. How many electrons have been lost or gained to form this ion? A) 2 lost B) 2 gained C) 1 lost D) 1 gained ## An electrostatic paint spray Static electricity can be used to spray a car with paint: Schematic: (A simple circuit with the following labels) - Paint gun nozzle has a positive charge. - Electrostatic generator - Car is negatively charged. The nozzle of the paint gun is connected to one terminal of an electrostatic generator. The other terminal is connected to the metal panel, which is earthed. ## Static Electricity- Demonstrations ## An electrostatic paint spray The spray gun is designed to produce tiny charged droplets of paint. Schematic: (A simple circuit with the following labels) - Paint gun nozzle has a positive charge. - Electrostatic generator - Car is negatively charged. As a result, the charged droplets are attracted to the car body panel. This gives a uniform coating of paint. Also, the droplets travel along the lines of force of the electrostatic field to reach hidden parts of the panel. ## Electric Charge(Guided) ### Group Task Draw straight lines to match each term with its description. | Term | Description | |---|---| | positive charge | having too many electrons | | negative charge | having no charge | | neutral | caused by a build-up of charge | | static electricity | having too few electrons | ### Individual Task Complete the Worksheet 17A Questions 1-2 1. Complete these sentences using words from the list. - positive - negative - neutral A plastic rod that has no charge is said to be **__**. When rubbed with a cloth, the rod becomes positive, so the cloth has **__** become **__**. Particles with a **__** charge have moved from the rod to the cloth. 2. a. Name the negatively charged particle found in an atom. b. A rod made from acetate has no charge. What can be said about the numbers of positive and numbers of negative charges in the rod? ### Want A Challenge! Is it possible to tell whether a charged object is positive or negative? What additional equipment(s) would be needed? ## Conductors and Insulators ## Investigating Conductors and Insulators Experiment to distinguish between conductor and insulator: Schematic: (A simple circuit including a lightbulb, a battery, crocodile clips, with the following labels) - Light Bulb - Popsicle stick - Coin - Crocodile clips - Battery ### Create a simple closed circuit by: * Connecting one wire between the battery and bulb. * Connecting another wire between the other end of the bulb and a crocodile clip. * Connecting the final wire to the other end of the battery and another crocodile clip. * Touch the two crocodile clips to each other to form a circuit and test the bulb. * Add the wooden popsicle stick, the coin or any other material between the crocodile clips, one at a time and check if the bulb lights up. * If the bulb lights up, the material connected between the clips is a good conductor. If it doesn’t, it is a good insulator. * Record your results on the table below. | Material | Bulb lights up (Yes or No) | Conductor or Insulator | |---|---|---| | Popsicle stick | | | | Coin | | | | Glass piece | | | | Paper | | | | Foil | | | ## Conductors and insulators ### INSULATORS – electrons are held tightly to their atoms so are not free to move, and so do not conduct electricity (but electrons can be transferred by rubbing – static charging). Eg. Plastics, glass, dry air ### CONDUCTORS – allow electrons to pass through them. Metals have “free” electrons between the individual atoms, and this makes them excellent conductors. The free electrons also make them good conductors of thermal energy (heat). Eg. Metals (copper, gold) and carbon ## Electric Force Objects in an electric field will experience an electric force. * Since force is a vector, the direction of this force depends on whether the charges are the same or opposite. * The force is either attractive or repulsive. * If the charges are the same (negative and negative or positive and positive), this force will be repulsive, and the second charged object will move away from the charge creating the field * If the charges are the opposite (negative and positive), this force will be attractive, and the second charged object will move toward the charge creating the field. * Objects with the same charge repel and objects with opposite charge attract. Schematic: (An arrow pointing upwards and a + symbol at the bottom, and an arrow pointing downwards with a - symbol at the top) When the negative particle enters the electric field, it feels a **__**ositive charge The size of the force depends on the strength of the field at that point This means that the force becomes: * Stronger as the distance between the two charged objects decreases * Weaker as the distance between the two charged objects increases The relationship between the strength of the force and the distance applies to both the force of attraction and force of repulsion. * Two negative charges brought close together will have a stronger repulsive force than if they were far apart. Repulsive forces decrease as like charges move further apart Schematic: (An arrow pointing downwards with a - symbol at the center of a circle. 4 arrows pointing outwards from the circle at the top and bottom) (An arrow pointing downwards with a - symbol at the center of a circle. 4 arrows pointing outwards from the circle at the top and bottom.) ## Where does static charge come from? Static charge can build up when two materials are rubbed together, such as a plastic comb moving through hair. When this happens electrons are transferred from one material to the other: One material ends up with more electrons, so it now has an overall **negative charge**. One material ends up with fewer electrons, so it now has an overall **positive charge**. ## Starter: 1. Which of these is the unit of charge? Choose one answer. A) ampere B) coulomb C) ohm D) volt 2. Which of these is the charge on an electron? Choose one answer. A) +1.6 C B) +1.6 × 10^-19 C C) -1.6 C D) -1.6 × 10^-19 C * Class Kick * Questions 1 -2 * Page 3 ## Creating static charge What is the name of the force between two materials that are rubbed together? **friction** An insulating material can be charged by friction. For example, if an insulator is rubbed with a cloth, it can become charged in one of two ways: ### A. Electrons move from the cloth to the insulator. ### B. Electrons move from the insulator to the cloth. ## Charging polythene If an insulator made of polythene is rubbed with a cloth, electrons move from the cloth to the insulator. What charge does the cloth now have? **The cloth is positively charged.** What charge does the polythene insulator now have? **The insulator is negatively charged.** ## Charging acetate If an insulator made of acetate is rubbed with a cloth, electrons move from the insulator to the cloth. What charge does the cloth now have? **The cloth is negatively charged.** What charge does the **__**polythene insulator now have? **The insulator is positively charged.** ## Investigating Charging by Friction The aim of this experiment is to investigate how insulating materials can be charged by friction. ### Experimental Setup: Schematic: (A simple diagram with the following labels) - Nylon string - Polythene rod - Rod of other insulating material - Cradle - Wooden stand ### Method: 1. Take a polythene rod, hold it at its center and rub both ends with a cloth. 2. Suspend the rod, without touching the ends, from a stand using a cradle and nylon thread 3. Take a Perspex rod and rub it with another cloth 4. Without touching the ends of the Perspex rod bring each end of the Perspex rod up to, but without touching, each end of the polythene rod 5. Repeat for different materials ### Analysis of Results * When two insulating materials are rubbed together, electrons will pass from one insulator onto the other insulator. * A polythene rod is given a negative charge by rubbing it with the cloth This is because electrons move from the cloth to the rod Electrons are negatively charged hence the polythene rod becomes negatively charged * If the material is repelled (rotates away) from the polythene rod, then the materials have the same charge. * If the material is attracted to (moves towards) the polythene rod, then they have opposite charges Schematic: (A polythene rod with arrows pointing upwards) (An acetate rod with arrows pointing downwards) ## Detection of Charges ### Experiment: * Repeat the experiment with a glass rod rubbed with a silk cloth. * When the glass rod is rubbed with silk cloth, glass quickly loses electrons, and silk takes electrons out of the glass rod. So, after rubbing the glass rod becomes positively charged and the silk gets negative charge * If the rods A and B are both positive, they will again repel each other. * If rods A and B are oppositely charged (one is polythene and the other glass), then the rods will attract each other. * Now repeat the experiment with rod A positive or negative and rod B, uncharged. The two rods attract each other. * This means the rods are attracted if rod B is oppositely charged or uncharged to rod A. Schematic: (A simple diagram with two rods connected by a string) ### Rub a polythene rod with a woolen cloth, making sure that you rub the full length of the rod. ### The polythene, when rubbed with woolen cloth will gain electrons from the cloth, making it negatively charged (and leaving the cloth positively charged) ### Hang the polythene rod (A) in the paper stirrup so that it is free to turn. ### Rub another polythene rod (B) and bring one end close to an end of the suspended rod. ### The two rods will repel as they have the same charge. Attraction may occur between two oppositely charged bodies or a charged body and an uncharged one. However, in repulsion, there are two bodies have the same charge. That is why repulsion is the sure test for charges. ## Attract or Repel | sphere 1 | sphere 2 | repel | attract | |---|---|---|---| | + | + | | x | | + | - | x | | | - | + | x | | | - | - | | x | ## Coulombs ## Conductor or insulator | Material | Conductor or insulator | |---|---| | Copper | | | Rubber | | | Wood | | | Iron | | | Gold | | ## Gained or lost electrons ## Electric field: ## Conductors and Insulators ### Conductors A conductor is a material that allows charge (usually electrons) to flow through it easily Examples of conductors are: * Silver * Copper * Aluminum * Steel Different materials have different properties of conductivity. Conductors tend to be metals: Schematic: (A table with the following labels) - Copper - Iron - Carbon - Water - Air - Glass - Rubber **Better conductors** **Better insulators** The lattice structure of a conductor with positive metal ions and delocalized electrons Schematic: (A circle representing an atom with the following labels) - Electrons from outer shell of metal atoms - Positively charged metal ions - Electrons are delocalized; They are free to move throughout the structure On the atomic scale, conductors are made up of positively charged metal ions with their outermost electrons delocalized. This means the electrons are free to move Metals conduct electricity very well because: * Current is the rate of flow of electrons. * So, the more easily electrons can flow, the better the conductor. ### Insulators An insulator is a material that has no free charges, hence does not allow the flow of charge through them very easily Examples of insulators are * Rubber * Plastic * Glass * Wood Some non-metals, such as wood, allow some charge to pass through them. Although they are not very good at conducting, they do conduct a little in the form of static electricity. For example, two insulators can build up charge on their surfaces and if they touch this would allow that charge to be conducted away. Overall, metals are very good conductors whilst non-metals tend to be good insulators ## Electric Field Objects with static charge create an electric field in the space around them. If other charges enter the field, then they will experience an electric force, attracting or repelling them from the object. Therefore, an electric field can be defined as: A region in which a charged object will experience an electric force. * Electric fields are represented by electric field lines. * The direction of an electric field at a point is the direction of the force on a positive charge at that point. * Fields lines always point away from positive charges and towards negative charges. * The strength of an electric field depends on the distance from the object creating the field. * The field is strongest close to the charged object - this is shown by the field lines being closer together. * The field becomes weaker further away from the charged object - this is shown by the field lines becoming further apart. Schematic: (A circle with a + symbol and arrows pointing outwards) (A circle with a - symbol and arrows pointing inwards) ## Electric Field The field lines around a charged conducting sphere are as if the charge was concentrated at the center of the sphere. The electric field lines for a charged, isolated sphere, such as a spherical conductor: * Point away from the center of a positive sphere. * Point towards the center of a negative sphere. Schematic: (A circle with a + symbol in the center and arrows pointing outwards) (A circle with a - symbol in the center and arrows pointing inwards) ## A uniform electric field, such as that between two parallel plates, are straight parallel lines from the positive plate to the negative plate and are equally spaced apart. Schematic: (A rectangle with + symbols and arrows pointing outwards ) * The electric field pattern between two oppositely charged spheres (or point charges) is slightly different and looks like: Schematic: (Two circles with + and - symbols in the center, and arrows pointing inwards and outwards) ## Socrative Static electricity ALZIBDEН ## Static electricity around us Where can static electricity be found in this lab scene? Schematic: (A scene including a Van de Graaff machine, a lightning bolt outside the window, a person rubbing a balloon, and the following label) - Clean smoke ## Charging by Friction Materials are charged by addition or removal of electrons from a material. All objects are initially electrically neutral, meaning the negative (electrons) and positive charges are evenly distributed. However, when the electrons are transferred through friction. When certain insulating materials are rubbed against each other they become electrically charged. This is called charging by friction. * The charges remain on the insulators and cannot immediately flow away. One becomes positive and the other negative. * An example of this is a plastic or polythene rod being charged by rubbing it with a cloth. Both the rod and cloth are insulating materials * This occurs because negatively charged electrons are transferred from one material to the other. * The material, in this case, the rod, loses electrons. Since electrons are negatively charged, the rod becomes positively charged. * As a result, the cloth has gained electrons and therefore is left with an equal negative charge. The object to which the electrons are transferred to becomes **negatively charged.** The object from which the electrons leave from becomes **positively charged**. The difference in charges leads to a force of attraction between itself and other objects which are also electrically neutral. * This is done by attracting the opposite charge to the surface of the objects they are attracted to. * In the example below, when the cloth and rod are rubbed together, the electrons are transferred to the cloth and leave from the rod. Schematic: (A simple diagram of a rod and cloth) - Uncharged cloth - Uncharged plastic rod - Negatively charged cloth - Positively charged rod ## Charging by contact and by induction ### By Contact: Schematic: (A simple diagram of a rod touching a sphere and a metal stand) ### By Induction : Schematic: (A simple diagram with a rod touching a sphere, a metal stand, a grounding wire, a connection to ground) ## Research time Where and How is Static Electricity Used in Our Everyday Lives? Google ## Uses of static electricity Static electricity can be dangerous, but it can also be useful, as long as it is used carefully. Examples of uses of static electricity are: 1. **__**Photocopiers 2. **__**Printers 3. **__**Spray painting ## Class Kick: ALL WRITE ROUND TABLE Schematic: (A round table with people sitting around it) ### Questions: FR - G1: 1 & 20 - G2: 3 & 4 - G3: 5 & 6 - G4: 7 & 8 - G5: 14 & 15 - G6: 18 & 19 ## Group work activity: 1. Assigned Questions: Each group will have one question related to Static electricity. You'll need to work together to answer it. 2. Answering in Turns: Within your group, each student will take turns answering one part of the question. So, we'll go one part at a time. 3. Discussion: Discuss your assigned question thoroughly. Share your knowledge and ideas with your group members. 4. Comprehensive Answers: Make sure your answers detailed and complete. If you're not sure about something, discuss it with your group to come up with the best response. 5. Sharing with the Class: After your group discussion, each group will take turns sharing their findings and answers with the whole class. ## Friction & Static Electricity Visual Challenge - Create a poster or presentation that explores the concept of static electricity and its relationship to friction in everyday life. Feel free to choose from the examples we've studied and include clear explanations, labels, and real-life instances. | Criteria | Marks | |---|---| | A clear explanation of friction and static electricity. | 3 | | Real-life examples of friction and static electricity. | 3 | | Diagrams, images, or animations to illustrate the concepts. | 4 | ## Assessment: QUIZIZZ Schematic: (A screen with the following labels) - QUIZ - Static Electricity - 10th grade - Physics - 0% accuracy - 0 plays