Electricity And Magnetism Ppt Grade 9

[Janne Desir]

IntroductionThe Grade 4 Physical Science Unit focuses on magnetism and electricity. All of the Grade 4 California Science Content Standards for Physical Science are addressed in this unit. By the end of the unit students will know: electricity and magnetism are related effects that have many useful applications in everyday life. Through a series of hands-on investigations students will experience the effects of magnetism and learn about static and current electricity. Students will design, build, and use: series and parallel circuits, a simple compass, and an electromagnet. Students will learn the role of electromagnets in the construction of electric motors and experience how electrical energy can be converted to heat, light, and motion. The Grade 4 Physical Science Unit is presented to students through a series of investigations, experiments, active learning experiences, questions, and assessments. Assessments include: pre-, post-, and 3 formative assessments.

Conceptual Flow Narrative: The Grade 4 Conceptual Flow Narrative for Physical Science: Matter builds on the concepts presented on conceptual flow graphic by describing the concept(s) addressed in each lesson and the links that connect each lesson to the next. Lessons are linked to the previous lesson and the lesson that follows via a conceptual storyline. This ensures the development of student understanding as students progress from one concept to the next.

After Lesson 4, students complete Formative Assessment #1. This assessment is aligned to the learning objectives of Lessons 1-4 and provides feedback to the teacher, students, and parents about what students have learned in the beginning of the unit. The teacher is able to use information from this formative assessment to determine if additional instruction is necessary for student understanding of the concepts presented in Lessons 1-4 before proceeding to the next section of the unit.

After Lesson 8, students complete Formative Assessment #2. This assessment is aligned to the learning objectives of Lessons 5-8 and provides feedback to the teacher, students, and parents about student understanding of phase change. The teacher is able to use information from this formative assessment to determine if additional instruction is necessary for student understanding of the concepts presented in Lessons 5-8.

An electromagnet is a piece of iron that becomes a temporary magnet when electricity flows through an insulated wire wrapped around the piece of iron. More coils of wire wrapped around the iron results in a stronger electromagnet. Students conduct an experiment to find out how to increase the strength of an electromagnet.

Focus:

In this unit, students will trace the path of electricity from the power plant, through their home, and to wall sockets. They will explore different devices that use electricity, as well as safety precautions around the use of electricity. Students will also investigate how magnets are used to produce electricity.

Students are familiar with many devices that use electricity based on day-to-day life. Students understand that certain devices need to be plugged in or turned on to work. However, they may not understand that the power behind that work is generated by electricity because they cannot see it. In fact, the only experience students may have in witnessing electricity is while watching a lightning storm. Electricity generated for everyday use often comes from human-made sources like batteries and power plants.

In this unit, students investigate phenomena associated with electricity and magnetism. They will further explore magnetism in Grade 3 Unit 1 Investigating Forces and electricity in Grade 4 Unit 1 Energy Transfer and Transformation.

The Student Books offer engagingly written and richly illustrated text on the topics specified for the unit. Each volume includes color photographs and illustrations and is intended to be read aloud with students across the instructional sequence of lessons.

In this unit, students connect their discoveries about Earth and life sciences with the physical sciences as they figure out the relationship between magnetism phenomena and electricity phenomena. In this lesson, students investigate the interactions between magnets and electricity. This page is a high-level extract of this lesson.

Electricity is closely linked to magnetism. Charged particles change the space around them. They produce an electric field, which is the area around a charge that can exert a force on other charged particles. Similar to magnets, charged particles either attract or repel one another. Particles that have an opposite charge attract one another within their electric field, while particles with the same charge repel each other within their electric field. Electrons are kept in orbit in their shells because the positive charge of the protons in the nucleus attracts the negatively charged electrons.

The strength of the field weakens with distance. Because of this, electrons in shells closest to the nucleus are tightly bound, while electrons in the outermost shell are much more loosely bound. When a force is applied, electrons in the outer shells can be pushed from one atom to another. Once that first electron has been pushed away from its atom, it moves to another atom. This movement of electrons causes electrons to all move in the same direction as one another.

Because electromagnets are made with electricity, they can be demagnetized when the electricity is turned off. This is possible because electromagnets form a circuit. A circuit is the circular path that electrons travel in a negative to positive direction.

For example, a light bulb is an object that does work. When electrons reach the light bulb in a circuit, they transfer electrical energy. The light bulb changes the electrical energy into outputs of light energy and heat. In a perfect system, the same amount of energy that was transferred through the circuit would be available to light up the bulb because of the conservation of energy. However, in the real world, some of the energy transfers out of the system due to resistance, which is the force opposing the current. The electrons then continue on their path. They return to the opposite side of the battery.

The way a circuit is put together affects the amount of electric current that can do work. Current is a measure of the rate that electric charge passes through a point in an electric circuit over time. It is measured in amps (A). The amount of work that can be done increases as current increases. For example, a fast current will cause a light bulb to be brighter than a slow current. This is because more electrons reach the bulb in the same amount of time.

As electrons in a conductor move in the same direction as one another, their movement produces a magnetic field around the wire conductor. The magnetic field around a straight wire is not very strong. However, if the wire is wrapped in a coil, the fields produced in each turn of the coil add up to create a stronger magnetic field. This is the idea behind an electromagnet: a tightly coiled wire produces a magnetic field when electricity passes through the wire. The electromagnet becomes magnetized when the circuit is closed. It becomes demagnetized when the circuit is open.

Electromagnets are an important part of electric motors, which are found in a wide range of household items, including electric screwdrivers, washing machines, automatic can openers, fans, electric toothbrushes, and many toys that move.

A motor is a machine that transfers an input of electrical energy into an output of kinetic energy. An electromagnetic motor has two parts: an outside permanent magnet and an inside electromagnet. The electromagnet becomes magnetized when the circuit it is part of is closed.

There are different ways to change the speed that a motor spins. The more coils an electromagnet has, the stronger magnetic field it will have. Because the electric current is so connected to the magnetic field, this stronger magnetic field causes the current to flow even faster. A faster current means that the electrons are moving faster. That faster movement creates a stronger magnetic field, which then causes the current to move even faster.

Once students understand the basic principles of magnetism phenomena, they create simple electric motors using permanent magnets and electromagnets to investigate the factors that affect how fast the motor spins.

The Shanghai Maglev is able to reach such speeds because it uses giant magnets to float over the tracks. (Maglev is short for magnetic levitation.) Floating above the tracks offers the trains a significant advantage. There is very little friction to slow the trains down. Engineers in the United States are discussing using maglev trains to connect the East and West Coasts.

Maglev trains work because they use a kind of magnet called an electromagnet. Electromagnets are tightly wound coils of wire that produce a magnetic field when electricity passes through the wire. They are useful in various technologies because the magnet can be turned off and on. This is different from permanent magnets, which stay magnetized without electricity.

Electromagnets become magnetized when electricity moves through the wire. Electricity is the flow of electrons through a conductor. Electricity is all around us. It is found in our bodies as electrical impulses and in the sky during storms as lightning. It also powers much of our modern world, turning on lights and powering motors, cell phones, and many other technologies.

Electricity happens because of the structure of matter. Remember that all matter is made of tiny particles called atoms. Atoms are made up of even smaller particles, including protons, neutrons, and electrons. Protons and neutrons are found in the nucleus, and electrons orbit the nucleus at different distances called shells. Protons have a positive charge (+), and electrons have a negative charge (-).

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