Light Waves & Sound Waves

light can come from:

sun, lightbulbs and excited atoms

Fluoresce

when external radiation bombards certain types of elements, the excited atoms fluoresce, giving off electromagnetic energy, often in the form of light

light can come from:

sun, lightbulbs and excited atoms

Fluoresce

when external radiation bombards certain types of elements, the excited atoms fluoresce, giving off electromagnetic energy, often in the form of light

What terms are used when describing waves?

wavelength, amplitude, and frequency

crest

top of a wave

trough

bottom of a wave

amplitude

distance between crest and trough

wavelength

distance from one crest to the next

frequency

how often a crest passes a point/how many crests pass a given point per second

Higher frequency results from

high speed and/or shorter wavelengths

Radio waves

Ultraviolet waves

X-Ray

Radio waves have a long wavelength and can pass through your body without damaging

Ultraviolet Waves have short wavelengths and are more likely to collide with molecules in your body and cause damage (ie sunburns or skin cancer)

X Rays have very short wavelength and can be very damaging

What is one of the most damaging waves?

gamma rays

Reflection

of light occurs when light returns after bouncing off of an objects (ie a mirror)

travels in straight lines

Refraction

of light occurs when light is bent while passing from one medium (gas, liquid, solid) onto the other

ie rainbows

Matter generally absorbs light, and what we see as color is

the particular wavelength that is not absorbed

What is happening if an object appears white?

it is either reflecting or emitting all visible wavelengths

What is happening if an object appears black?

it is absorbing all visible wavelengths. this is why asphalt is hotter than cement

Greenhouse Gases

like water vapor, carbon dioxide, and methane warm the earth by trapping some of the heat radiated from the Earth’s surface

this is necessary but causes problems like global warming when we accelerate this process

How do sound waves travel?

sound waves require a medium and travel much slower than light waves (cant travel in space)

The Doppler Effect

the motion of objects emitting or reflecting sound waves changes their frequency

can also be used to track weather