Wave interactions EQ: How is energy transferred in waves? Obj: Describe how waves interact with matter and each other

How do waves interact with matter When waves interact with a different type of medium, they are either reflected, refracted or absorbed. https://www.youtube.com/watch?v=k0eGjaEWpPU

How do waves interact with matter 1. Reflection: The bouncing of a wave off a surface and it heads in a different direction

What is the Law of reflection? Turn and Talk: what do you think this law means in your own words

What is the Law of Reflection? The angle the wave hits the material is equal to the angle it is reflected. Law of reflection: the angle of incidence = the angle of reflection

2. Refraction: When a wave bends or changes direction because its speed changes as it goes from one medium to another

The wave will try to curve 3. DIFFRACTION: Is change in direction of a wave when it bends around an opening or boundary. The wave will try to curve A moving object has energy. The moving object can transfer energy to a nearby medium, creating a wave.

4. Absorption - Disappearance of a waves energy into the medium it is in. Opposite of reflection Amount transmitted depends on speed of the wave and the material Transparent, translucent, or opaque

transparent objects Transmit all of the waves clear image. Ex: window

translucent objects Transmit and scatter it blurry image Ex: frosted glass

opaque objects Absorbs all the waves Waves stop EX door

Transparent objects transmit all of the waves - Translucent objects transmits it and scatters it Opaque objects - no light waves are transmitted – absorbs it

Label the type of light interaction shown in each of the blanks below: 2. 1. 3. 4.

How is the light interacting with each medium?  

What is wave interference INTERFERENCE: When waves move through a medium at the same time -The energy of the waves may interact by adding together or canceling out as they pass. (Tsunami waves) - Once the waves have passed each other, they continue unchanged by the interaction.

Interference Constructive Interference – When two waves of different sizes collide to make a wave with larger amplitude. They add their energy together Destructive Interference – When two waves combine to form a wave with a smaller amplitude.

Close: Complete summary questions Objective check – where are you? 1 – what is a wave 2 – describe reflection, absorbtion, refraction 3 – draw or identify reflection, absorbtion, refraction 4 – Describe transmission of waves through different materials

EM (Electromagnetic Waves) How do electromagnetic waves differ from mechanical waves? EM waves do NOT need a medium to travel through.

EM Waves Every time you feel the sun’s heat, listen to your MP3 player, or pop a bag of popcorn in the microwave, you are using a different form of the electromagnetic energy. EM waves make these events possible.

EM Waves EM waves are transverse waves that have some electrical properties and some magnetic properties. It consists of changing electric and magnetic fields. EM waves travel as vibrations in electric and magnetic fields.

EM Waves EM waves vary based on wavelength, energy and frequency. Electromagnetic energy is created by vibrations (just like mechanical waves). This produces waves that carry the energy. Each EM wave emits at different energy levels. The collection of all EM frequencies is known as the “Electromagnetic Spectrum”.

Electromagnetic Spectrum

Electromagnetic Spectrum 1. Radio waves are used to transmit radio and television signals. Radio waves have wavelengths that range from less than a centimeter to tens or even hundreds of meters. Longest wavelength, lowest frequency and least amount of energy. They travel long distances by reflecting their signals off Earth’s atmosphere or off satellites.

Electromagnetic Spectrum 2. Microwaves – shorter wavelengths, higher frequencies, and more energy than radio waves. Cell phones and radar are two uses of microwaves. 3. Infrared Light - is the region of the electromagnetic spectrum that extends from the visible region to about one millimeter (in wavelength). Infrared waves include thermal radiation. Associated with heat

Electromagnetic Spectrum 4. Visible Light – The range of EM waves that can be detected by the human eye. Longest wavelength is of visible light is red. Shortest wavelength of visible light is violet. The color we see is determined by the way the light interacts with the object. How it is reflected and how it is transmitted. 400 – 700 nm (nanometers)

Visible Light Each of these colors actually corresponds to a different wavelength of light.

How Roy G. Bv Lost a Vowel The sequence of colors red, orange, yellow, green, blue, and violet may be remembered by memorizing the name of that fine fellow "ROY G. BV". This was originally "ROY G. BIV", because it used to be common to call the region between blue and violet "indigo". In modern usage, indigo is not usually distinguished as a separate color in the visible spectrum; thus Roy no longer has any vowels in his last name.

Electromagnetic Spectrum 5. Ultraviolet Light (UV)- Higher frequency than visible light and carry more energy. Can damage or kill living cells Tan skin by the sun or tanning bed

Electromagnetic Spectrum 6. X-rays - high energy waves which have great penetrating power and are used extensively in medical applications and in inspecting welds. The wavelength range is from about ten billionths of a meter to about 10 trillionths of a meter. Short wavelengths and high frequencies allow them to travel through skin, but not bone (more dense)

Electromagnetic Spectrum 7. Gamma Rays – Shortest waves, with the highest frequency (and highest energy). They are more penetrating than X-rays Can kill living cells Used to sterilize medical equipment

How do prisms separate visible light? When light shines through a prism, the glass changes the behavior of each light wave according to the wave's wavelength. This property of glass is known as its refractive index. The prism changes the direction the light is traveling. As a result, what goes in as ordinary white light comes out separated into a spectrum of different colors. That's because white light is really all those wavelengths mixed together.

Visible Light Each of these colors actually corresponds to a different wavelength of light.

How Roy G. Bv Lost a Vowel The sequence of colors red, orange, yellow, green, blue, and violet may be remembered by memorizing the name of that fine fellow "ROY G. BV". This was originally "ROY G. BIV", because it used to be common to call the region between blue and violet "indigo". In modern usage, indigo is not usually distinguished as a separate color in the visible spectrum; thus Roy no longer has any vowels in his last name.