4th Grade – Unit 2

4th unit 2

In this unit, we will explore the forces of magnetism and static electricity. As we go through these lessons, we will engage in many activities to discover characteristics of magnets are and how they are able to attract certain materials. Once we know what causes a substance to be magnetic, we will also be able to create several different types of magnets.

As we study static electricity, we will observe how electrons – tiny negatively charged particles – can build up on certain materials to create a stored electrical charge. With a better understanding of magnetism and electricity, we will see the relationship between these two forces. We will also both use electrical current to create magnetic fields and use magnetic energy to generate electrical currents.

 

PowerPoint Presentations


04_02_01_pptLesson 1: What is a Magnet? Most people are familiar with magnets and some of their properties. In this lesson, however, we will be looking at the three defining characteristics of a magnet. First, all magnets will exert a pulling force on ferromagnetic materials: objects made of iron, nickel, or cobalt. Second, all magnets produce a magnetic field. Last, all magnets have the ability to attract or repel other magnets. It is important to understand that in order to be a magnet, an object must possess each of these three properties. In our later lessons, we will be looking at each of these characteristics in more detail and conducting experiments to study and observe each of these properties. Download PDF Notes


04_02_02_pptLesson 2: Ferromagnetic Substances In lesson 2, we will explore the first property of magnets – their ability to attract ferromagnetic substances. A ferromagnetic substance is simply a substance that be attracted to, or pulled by, a magnet. The three most common ferromagnetic elements are iron, nickel, and cobalt. Any object containing one or more of these elements will, to an extent, be pulled on by a magnet. Often these ferromagnetic metals and other elements are combined to form an alloy – a mixture of two metals or a metal and a nonmetal. These alloys will also demonstrate ferromagnetic properties. During this lesson, we will be testing and observing the ferromagnetic properties of a variety of materials. Download PDF Notes


04_02_03_pptLesson 3: Magnetic Fields In our third lesson of this unit, we will be learning about magnetic fields – the invisible lines of force that surround a magnet. Like many other forms of energy, our eyes are not able to see a magnetic field, but we are able to observe its effects. When a magnet attracts a ferromagnetic object, it is because of the force of its magnetic field. During this lesson, we will be using two ferromagnetic materials – iron filings and ferrofluid to observe the shapes and strengths of a variety of magnetic fields. These substances align to the lines of force in the magnetic fields to allow us to observe their effect.  Download PDF Notes


04_02_04_pptLesson 4: Magnetic Attraction and Repulsion Lesson 4 examines the interaction of magnetic fields with other magnets. Forces in general can be defined as a push or a pull on an object, and magnetic force is no different. We have already discussed how magnets attract, or pull on ferromagnetic objects and materials. In this lesson, we will see how magnets can also exert forces on other magnets. A magnet is able to push or pull on another magnet. This pulling force that will cause two magnets to stick together is called attraction. Magnets attract when their opposite poles face one another. When like poles face one another, however, the two magnets will push away from one another. This pushing force between two magnets is called repulsion. Download PDF Notes


04_02_05_pptLesson 5: Electromagnets In lesson 5, we will be learning how electrical current can be used to create a temporary magnet called an electromagnet. As electricity flows through a coil of wire around a ferromagnetic material, it will create a magnetic domain in the ferromagnetic material. The amount of current present and the tightness of the coiled wire affect the strength of the electromagnet. During this lesson we will create a simple electromagnet using an iron nail and a battery. We will look at other more powerful types of electromagnets as well, such as ironclad electromagnets and other larger electromagnets. We will also explore several uses of electromagnets along with their benefits and disadvantages compared to permanent magnets. Download PDF Notes


04_02_06_pptLesson 6: Static Electricity Electricity is the result of negatively-charged subatomic particles called electrons. When these electrons flow through a conductive material it creates electrical current. Sometimes, however, these electrons can build up on an object creating a charge of static electricity. Static charges can be created by two objects rubbing against one another. This static electricity can be discharged creating an electric shock, such as by wearing socks while dragging your feet across a carpeted floor and then touching a metal surface.   An object with a negative charge from this buildup of electrons can also behave much like a magnet, attracting to positively charged objects and repelling other negatively charged objects. Download PDF Notes

 

Resources and Other Documentation


04_02_guided_notesUnit 2 Guided Notes The guided notes for each unit provide students with a printable copy of notes summarizing the content from each class. Blanks are inserted into the notes where key facts or content should appear. As information is covered during class, students should write missing content into the blanks to complete the guided notes. These guided notes may also be used as a review tool for unit tests. Students may print a copy of the guided notes and fill in the missing content. This can be checked using the complete PDF notes for each lesson.