What makes sound?: Vibrations
Can sound travel in space?: No; it needs matter to travel through
Does sound travel faster in air or water?: Water
Sound travels fastest through: Solids
Pitch: How high or low a sound is
What determines pitch?: Frequency
Volume (loudness): How strong a sound is; depends on amplitude
Unit of loudness: Decibel
Echo: A sound that bounces off a surface and comes back
Ultrasound: Sound with frequency too high for humans to hear
Infrasound: Sound with frequency too low for humans to hear
Range of human hearing, roughly: 20 to 20,000 hertz
Sonar: Using sound echoes to find objects underwater
Echolocation: Animals such as bats and dolphins using echoes to find things
Speed of sound in air, roughly: 343 meters per second
Sonic boom: A loud noise made when something travels faster than sound
Speed of light: About 300,000 kilometers per second
Why do we see lightning before we hear thunder?: Light travels much faster than sound
Light travels in: Straight lines
Reflection of light: Light bouncing off a surface
Refraction of light: Light bending when it enters a new material
What does a prism do?: Splits white light into a rainbow of colors
Colors of the rainbow in order: Red, orange, yellow, green, blue, indigo, violet
Which color of visible light has the longest wavelength?: Red
Which color has the shortest wavelength?: Violet
Transparent: Lets light pass through clearly
Translucent: Lets some light through but scatters it
Opaque: Blocks light
Shadow: A dark area where an object blocks light
Convex lens: A lens thicker in the middle; makes light converge
Concave lens: A lens thinner in the middle; makes light spread out
Plane mirror: A flat mirror that forms an image the same size as the object
Concave mirror: A mirror curved inward, like the inside of a spoon
Convex mirror: A mirror curved outward, used as a car side mirror
Primary colors of light: Red, green and blue
Primary colors of paint (traditional): Red, yellow and blue
Why is the sky blue?: Air scatters blue light more than other colors
Why are sunsets red?: Light passes through more air, scattering the blue away
Electromagnetic spectrum order, long to short wavelength: Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray
Radio waves are used for: Radio, TV and phones
Microwaves are used for: Cooking and communications
Infrared is felt as: Heat
Ultraviolet light: Causes sunburn and tanning
X-rays are used for: Seeing bones and inside objects
Gamma rays: The highest-energy waves
Laser: A narrow beam of light of one wavelength
Fiber optics: Thin glass fibers that carry light signals
Total internal reflection: Light bouncing entirely inside a material like glass or water
Mirage: An image caused by light bending in hot air
Wave: A disturbance that carries energy
Crest: The highest point of a wave
Trough: The lowest point of a wave
Amplitude: The height of a wave from rest position
Wavelength: Distance between two crests
Frequency: Waves per second
Medium: The material a wave travels through
Resonance: A strong vibration when something is pushed at its natural frequency
Interference: Waves combining to be bigger or smaller
Doppler effect: A siren sounds higher as it approaches and lower as it leaves

Free flashcards from Peabody at peabody.kids/flashcards/phys-light-sound-waves