# Waves, Sound, and Light Chapter 3.

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Waves, Sound, and Light Chapter 3

Bell Work 11/29/10 Please get a new bell work sheet. Write each statement then decide if they are true or false, if false correct them. Mechanical waves transfer energy through a vacuum. A wave is a disturbance that transfers energy. An example if a longitudinal wave is a water wave.

Bell work 11/25/09 List the colors of the visible light spectrum in order from longest wavelength to shortest wavelength. What are the 7 parts of the electromagnetic spectrum?

Bell Work 12/2/09 What are EM waves measured in?
Give two examples of using a radio wave. Give 3 examples of using a microwave. List the colors of visible light from longest wavelength to shortest wavelength.

Bell Work 11/30/09 Please use complete sentences Give an example of using a radio wave. Give an example of using a microwave. Give an example of using an x-ray.

1.1 Vocab Electromagnetic wave – a disturbance that transfers energy through a field Radiation – energy that moves in the form of EM waves

How EM waves form and sources of EM waves
Electric and magnetic fields make up EM waves Many of the EM waves on Earth’s environment come from the Sun. Stars give off EM waves but since they are so far away not many of their waves hit the Earth Technology is also a source of EM waves

Bell Work 11/30/10 What do electromagnetic waves transfer energy through? What is radiation? How does a microwave cook food?

Electromagnetic spectrum
The range of all EM frequencies The spectrum goes from the ______ frequencies to the _______frequencies ______-frequency EM waves with more electromagnetic vibrations per second have more energy than _____-frequency EM waves

Measuring EM Waves EM wave frequency is measured in _____ (Hz) One hertz equals one cycle per ______

Welcome to December Bell Work 12/1/10
What is the electromagnetic spectrum? State whether each statement is true or false. If false make the statement true. 2. Mechanical waves transfer energy through a vacuum. 3. A wave is a disturbance that transfers energy. 4. Most EM waves are invisible but detectable.

Radio waves Have the ______ wavelengths, the ______ frequencies, and the ______ energies Examples of radio waves are AM/FM radio and broadcast television

Microwaves EM waves with ______ wavelengths, higher frequencies, and _____ energy than other radio waves Radar – radio detection and ranging. Used to control air traffic at airports, analyze ________ conditions and measure the speed of a moving vehicle Radar led to the invention of ________ ovens Cell phones – radio transmitter and receiver that uses ________

Infrared Light Type of EM wave most often associated with ______
Sometimes referred to as _____ rays You can feel it as warmth coming from the sun, a fire, or a radiator Infrared lamps are used to provide ______ in bathrooms and to keep food warm after its been cooked Some animals can see in _____ light

Visible Light The part of the EM spectrum that _____ eyes can see.
Longest wavelengths are _____ all the way to violet ROY G BIV Red, Orange, Yellow, Green, Blue, Indigo, Violet

Ultraviolet Light Has more energy than _____ light
The waves in this range can ______ your skin and eyes Sun block and UV-protection sunglasses are designed to filter out the _______ frequencies UV light can be used to sterilize medical instruments and food by _____ harmful bacteria UV light causes skin cells to _______ vitamin D which is essential to good health UV light is ______ to some animals. Bees and some other insects

X-rays Has a very ______ frequency and ______
Pass easily through soft tissues of the body, but are absorbed by the _____ The _______ pass through exposing the film where there is no bone When getting x-rays other parts of the body are covered with a _____ vest to block the x-rays

Gamma rays ________ frequencies and energies of any ___ waves
Produced by some radioactive substances as well as the ____ and other _____ Gamma rays can penetrate the soft and the hard tissues of the body, killing normal cells and causing cancer cells to develop Gamma rays can also be used to kill _____ cells and _____ tumors

Bell Work 12/3/09 Which group from the EM spectrum has the highest frequencies? Which group pass easily through soft tissues of the body, but are absorbed by the bone? What can you use to filter out the high frequencies of UV rays? Which EM wave is most associated with heat?

Bell Work 12/4/09 Predict what would happen if you kept a green plant in the dark for one month. Explain why. (at least 3 sentences)

Vocab 3.3 Incandescence – the production of light by materials at high temperatures Luminescence – the production of light without the high temperature. Many organisms produce their own visible light through this.

Bioluminescence – production of light by living organism
Bioluminescence – production of light by living organism. These organism produce light from chemical reactions rather than intense heat. Fluorescence – occurs when a material absorbs EM radiation of one wavelength and gives off EM radiation of another.

Bell Work 12/5/09 What happens to the speed of EM waves in a vacuum?
What happens when microwaves encounter water? What produces the most EM waves on Earth?

Light 3.4 Notes Transmission – the passage of an EM wave through a medium. If the light reflected from objects did not pass through the air, windows, or most of the eye, we could not see the objects

Absorption – the disappearance of an EM wave into the medium
Absorption affects how things look, because it limits the light available to be reflected or transmitted

How Materials Transmit Light
Transparent materials allow most of the light that strikes them to pass through. Translucent materials transmit some light, but they also cause it to spread out in all directions. Opaque materials do not allow any light to pass through them, because they reflect light, absorb light, or both

Scattering – the spreading out of light rays in all directions, because particles reflect and absorb the light Fog or dust in the air, mud in water, and scratches or smudges on glass can all cause scattering Scattering creates a glare and makes it hard to see even through a transparent material

Polarization – a quality of light in which all of its waves vibrate in the same direction
Polarizing filters reduce glare and make it easier to see objects Prism – a tool that uses refraction to spread out the different wavelengths that make up white light Prisms split light into colors by refracting wavelengths in different amounts

Color Reflection and Absorption
The color of an object or material is determined by two factors the wavelengths it absorbs and those it reflects The wavelengths present in the light that shines on the object

A material that reflects all wavelengths of visible light appears white
A material that absorbs all wavelengths of visible like appears black A green lime absorbs most wavelengths but reflects green, so the lime looks green

Primary Colors of Light
The human eye can detect only 3 color bands: red, green, and blue Your brain perceives these three colors and various mixtures of them as all the colors Primary colors – red, green, and blue – can be mixed to produce all the possible colors

Primary Pigments Materials can be mixed to produce colors just as light can Materials that are used to produce colors are called pigments Primary pigments – cyan, yellow, and magenta

Bell Work 12/8/09 What color is something that absorbs all the colors?
What color is something that reflects all colors? If an object absorbs most wavelengths but reflects violet what color will it be?

Bell Work 12/9/09 – (fill in the blanks)
Bioluminescent animals produce light through _________. When light is absorbed into a medium, the waves ________ in the medium. The primary pigments create colors through _____________ mixing. An electromagnetic wave transfers energy through a ______. Most of the visible EM waves on Earth come from the ______.