Electromagnetic Energy and Waves

• This study guide covers waves, electromagnetic energy, optics, and sound.

Lesson 1: Waves

• Energy is transferred in a wave.
• Frequency and wavelength are related.
• Amplitude relates to wave energy, using a model.
• Transverse and longitudinal waves have components.
• Longitudinal and transverse waves and their characteristics can be compared
• Wave energy has different applications.

Key Terms: Transverse Waves

• A transverse wave is a light wave.
• Frequency is how frequent the waves are.
• Amplitude is wave height (how high or low).
• Wavelength is the length of a wave.
• A crest is the top of a wave.
• A trough is the bottom of a wave.

Transverse Waves

• Locate the crest, trough, amplitude, and wavelength on a transverse wave.

Wave Relationships

• Increasing the wavelength in a wave lowers the frequency.
• Increasing the frequency of a wave lowers the wavelength.
• There is no relationship between amplitude and wavelength.
• Higher speed refers to higher frequency, while less energy mean less frequent waves.

Lesson 2: The Spectacular Spectrum

• Wave behavior of visible light can be described.
• Compare electromagnetic waves, considering wavelength, frequency, and energy.
• Determine how waves are reflected, absorbed, or transmitted through materials.
• Major forms of electromagnetic energy have everyday scenarios.
• Describe how the law of reflection explains why colors are seen

Electromagnetic Energy

• All electromagnetic energy travels as transverse waves at the speed of light.
• Electromagnetic waves are produced by the motion of electrically charged particles.
• All electromagnetic waves types, arranged by wavelength and frequency, are called the electromagnetic spectrum

Electromagnetic Spectrum forms ( Lowest energy to highest)

• Radio
• Microwave
• Infrared
• Visible Light
• Ultra Violet
• X-Ray
• Gamma

EM Radiation

• Radio waves are used to broadcast radio and television.
• Microwaves are used in cooking, radar, and telephone signals.
• Infrared transmits heat from the sun, fires, and radiators.
• Visible light permits beings to see.
• Ultraviolet can cause skin cancer and is absorbed by skin from the sun.
• X-rays allow viewing inside of bodies and objects.
• Gamma rays are used in medicine for killing cancer cells and are the highest energy type of EM radiation.

Visible Light

• If there is no light, light waves are not able to be reflected off any surface to reach our eyes.
• Wavelength determines the color of the light.

EM Relationships

• From left to right: As electromagnetic energy goes from Radio waves to Gamma
• Wavelength decreases, Frequency increases, and Energy Increases.

Lesson 3: Optics

• Plan and conduct investigations related to the refraction, reflection, and diffraction of waves.
• Images formed by concave, convex, and plane mirrors and lenses can be identified.
• Uses of mirrors and lenses in everyday life are identifiable and useable.

Three Types of Light Wave Behaviors

• Reflection occurs when light waves bounce back from an object.
• Diffraction is the bending of waves around corners of an obstacle or through an aperture.
• Refraction occurs when light waves bend when going through a new substance.

Lenses

• Concave lenses correct shortsightedness and focus light outwards
• Convex Lenses correct farsightedness and magnify images
• Plane mirrors appear simply as mirrors

Mirrors

• The picture is incorrect because the light is not reflecting at the same angle.
• The law of reflection states that the angle of the incident ray will equal the angle of the reflected ray.
• Light waves are transverse and travel in a vacuum.

Lesson 4: Sound

• Mechanical waves being reflected, absorbed, or transmitted can be described using a model.
• An investigation related to sound can be planned and conducted.
• Speed of sound through various materials can be compared.
• The property of a sound wave can be identified that corresponds to its loudness.
• Predict pitch related to frequency.
• Interference and resonance can be Illustrated.

Frequencies and sound waves

• Constructive interference forms a new wave that improves the sound for the listener when two waves of identical wavelength are in phase.
• Decibels are used as the units to measure how loud or soft a sound.
• Pitch is how high or low a sound is.
• Echoes are a sound or series of sounds caused by the reflection of sound waves from a surface back to the listener.
• Resonance happens when sound waves cause something else to vibrate because they have the same frequency.
• Intensity is the amount of energy flowing through a wave per unit of time, measured in decibels.
• Destructive interference occurs when two sound waves of opposite directions (phases) hit each other, and the sound is canceled.
• Sound waves travel fastest through Solids.
• Intensity describes how high or low a sound seems to a person.
• Pitch explains the difference between a woman's soprano voice and a man's bass voice.