# ALEX Classroom Resource

## How Is a Radio Wave Emitted?

Classroom Resource Information

Title:

How Is a Radio Wave Emitted?

URL:

Content Source:

PBS
Type: Informational Material

Overview:

The sound produced for a radio broadcast may take three different forms and travel dozens of miles before it comes out of your loudspeaker. This illustrated essay from A Science Odyssey Web site explains the conversion of electrical signals to radio waves.

Content Standard(s):
 Science SC2015 (2015) Grade: 8 Physical Science 19 ) Integrate qualitative information to explain that common communication devices (e.g., cellular telephones, radios, remote controls, Wi-Fi components, global positioning systems [GPS], wireless technology components) use electromagnetic waves to encode and transmit information. Unpacked Content Scientific And Engineering Practices:Obtaining, Evaluating, and Communicating InformationCrosscutting Concepts: Structure and FunctionDisciplinary Core Idea: Waves and Their Applications in Technologies for Information TransferEvidence Of Student Attainment:Students: Use qualitative information to explain how communication devices use electromagnetic waves to encode information. Use qualitative information to explain how communication devices use electromagnetic waves to transmit information.Teacher Vocabulary:Qualitative Information Communication devices (e.g., cellular phone, Global Positioning System (GPS), remote control, Wi-Fi, etc.) Electromagnetic waves Energy Energy wave Electric field Magnet Magnetic field Mechanical wave Vacuum Frequency Wavelength Crest Medium Amplitude Displacement Rest position Encode TransmitKnowledge:Students know: Electromagnetic waves are a form of energy waves that have both an electric and magnetic field. Electromagnetic waves are different from mechanical waves in that they can transmit energy and travel through a vacuum. The different types of electromagnetic waves have different uses and functions in our everyday lives. Electromagnetic waves differ from each other in wavelength, frequency, and energy, and are classified accordingly. Wavelength is the distance between one wave crest to the next. Frequency refers to how often the particles of the medium vibrate when a wave passes through the medium The amount of energy carried by a wave is related to the amplitude of the wave. A high energy wave is characterized by a high amplitude; a low energy wave is characterized by a low amplitude. The amplitude of a wave refers to the maximum amount of displacement of a particle on the medium from its rest position. Electromagnetic waves can be used to encode information. Electromagnetic waves can be used to transmit information. Examples of common communication devices may include cellular telephones, radios, remote controls, Wi-Fi components, global positioning systems (GPS), and wireless technology components.Skills:Students are able to: Gather evidence sufficient to explain a phenomenon that includes the idea that using waves to carry digital signals is a more reliable way to encode and transmit information than using waves to carry analog signals. Combine the relevant information (from multiple sources) to articulate the explanation.Understanding:Students understand that: Common communication devices use electromagnetic waves to encode and transmit information.AMSTI Resources:AMSTI Module: Electricity, Waves, and Information Transfer Alabama Alternate Achievement Standards AAS Standard: SCI.AAS.8.19- Recognize that common communication devices use electromagnetic waves to transmit information, and that these electromagnetic waves are invisible to the human eye.
Tags: electrical signal, electromagnetic, radio, wave