Understanding Light and Sound

A set of vocabulary flashcards covering the definitions, properties, applications, and innovations of light and sound energy based on the lecture transcript.

Energy

The ability to do work or cause change; it can make objects move, produce light or sound, and change temperature.

Light Energy

A form of energy that allows us to see objects, such as when electrical energy in a flashlight changes into light energy.

Characteristics of Light

Light travels in straight lines, moves very fast, can travel through empty space, and can be reflected, refracted, and absorbed.

Speed of Light

Approximately $3 \times 10^8\,m/s$.

Natural Sources of Light

Sources that occur in nature, such as the Sun, stars, and fireflies.

Artificial Sources of Light

Man-made sources such as light bulbs, flashlights, and LED lamps.

Reflection

The bouncing back of light when it strikes a surface, such as in mirrors or searchlights.

Refraction

The bending of light as it passes through different materials, such as in eye glasses and prisms.

Absorption

Occurs when materials take in light energy; dark-colored objects absorb more light and heat.

Dispersion

The separation of white light into its constituent spectrum of colors (violet, indigo, blue, green, yellow, orange and red) when passed through a glass prism.

Fiber optics

A light application used for internet and telecommunication.

Sound Energy

A form of energy made by vibrations that travels in waves and requires a medium (solid, liquid, or gas) to travel.

Pitch

The degree of lowness and highness of sound; high notes are heard with fast vibrations, and low notes are heard with slow vibrations.

Frequency

The number of vibrations within a period of time, measured in Hertz ($Hz$). High frequency corresponds to high pitch.

Speed of Sound

How fast a wave moves through a substance; it travels fastest in solids, slower in liquids, and slowest in gases.

Wavelength

The physical distance of one complete wave cycle, such as the distance between two matching parts of adjacent compressions.

Sonar

Categorized in the notes under medicines; used for ships and submarines.

Ultrasound

Categorized in the notes under navigation; used for imaging.

Amplifiers, Speakers, and Microphone

Devices where microphones convert sound waves into electrical signals and speakers boost them to higher audio frequencies.

Hologram Technology

Uses light diffraction to construct photographic, three-dimensional light fields used in security features and entertainment.

LASER

Stands for Light Amplification by Stimulated Emission of Radiation; creates highly concentrated, precise beams of light for medical and scanning use.

LED

Stands for Light Emitting Diode; energy-efficient, long-lasting semiconductors that convert electricity directly into light.

Soundproofing

Innovations like specialized dense foam and micro-perforated acoustic panels that absorb and block sound waves to control noise pollution.