Sound & Light Vocab Quiz

Sound

Energy produced by vibrations that travels through a medium and can be heard. Sound is a mechanical, longitudinal wave.

Vibration

A back-and-forth movement of particles or an object.

Longitudinal wave

A wave in which particles vibrate parallel to the direction the wave travels, creating compressions and rarefactions.

Mechanical wave

A wave that transfers energy through matter and requires a medium. It can be transverse or longitudinal.

Medium

The matter through which a wave travels, such as a solid, liquid, or gas.

Volume

How loud or soft a sound is. Greater amplitude produces greater volume.

Amplitude

The maximum distance of vibration from the resting position. Greater amplitude means louder sound; for light, greater intensity.

Decibel (dB)

The unit used to measure sound level or loudness.

Pitch

How high or low a sound is; determined by frequency. Higher frequency means higher pitch.

Frequency

The number of waves or vibrations passing a point each second. Higher frequency produces higher-pitched sound.

Hertz (Hz)

The unit of frequency. One hertz equals one vibration or cycle per second.

Absorption

Matter takes in a wave's energy, often converting it to thermal energy. Soft materials tend to absorb sound; materials can also absorb light.

Doppler effect

An apparent change in observed frequency caused by relative motion between a source and an observer. Approaching means higher frequency (higher sound pitch); moving apart means lower frequency (lower sound pitch). It applies to sound and light.

Echo

A reflected sound heard again after it bounces off a surface.

Echolocation

Locating objects using reflected sound waves, often high-frequency sounds.

Light

Radiant energy, such as energy emitted by the Sun or a lamp. Light can travel through a vacuum.

Electromagnetic spectrum

The full range of electromagnetic waves: radio, microwave, infrared, visible, ultraviolet, X-ray, and gamma ray.

Transverse wave

A wave whose vibrations are perpendicular (at right angles) to the direction it travels. Light is transverse.

Visible light spectrum

The small part of the electromagnetic spectrum that human eyes detect: red, orange, yellow, green, blue, indigo, violet (ROYGBIV).

Vacuum

A region with no matter or particles. Light can travel through a vacuum, but sound cannot.

Intensity

The strength of light, related to brightness. Greater amplitude means greater intensity.

Convex lens

A lens thicker in the center than at the edges. It brings parallel light rays together and can magnify objects, depending on distance.

Concave lens

A lens thinner in the center than at the edges. It spreads light rays apart and makes objects viewed through it appear smaller.

Scattering

Light is redirected in many directions when it interacts with particles or matter.

Transmit

To pass through a substance or object. Transmitted light passes through rather than being absorbed or reflected.

Reflection

A wave bounces off a surface or barrier. Mirrors reflect light; echoes are reflected sound.

Transparent

Allows light to pass through clearly, so objects behind it can be seen distinctly. Example: clear window glass.

Translucent

Allows some light through but scatters it, so objects behind it appear blurry. Example: frosted glass.

Opaque

Does not allow light to pass through. Example: a wooden door.

Optics

The study of light, its properties, and its behavior.