Physics Unit 1: Wave Questions

The Glory:

basically a rainbow seen from above looking down. Therefore, the entire circle of the rainbow is seen. Usually seen from the mountains

What is iridescence and how is it produced? What are some examples?

-A lustrous rainbow like play of color that changes depending on your point of viewing -Can be formed from interference as well as diffraction If diffraction, then the colors seen are form the diffracted waves interfering with each other -Examples: oil slick, soap bubble, pear, butterfly wing

What is a mirage and how is it formed? Give some examples. What conditions are necessary to form them?

-A mirage is an optical phenomena produced from refraction or bending of light through heated atmosphere -The image can be inferior (below the object) of superior (above the object) which is determined by the motion of the atmosphere

Venus's Belt:

-A pinkish brown band that appears to be resting on the blue sky at dusk/dawn -It's formed in clear weather and is very common -Thin band of pink

Light Pillars:

-Are formed from reflection off the ice crystals high in the atmosphere -Usually are only seen in the higher latitudes -They can only be seen under certain atmospheric conditions -They show their own color therefore, the light is not refracted

Why do leaves change colors in the fall?

-As autumn comes to an end, plants and trees produce less chlorophyll due to the decreased amount of sunlight which regulates the production of chlorophyll -Chlorophyll has a constant decomposition rate, and the green begins to fade when chlorophyll starts to decompose -As the chlorophyll decomposes the two other pigments become the more dominant and the various colors start showing up

Why does your voice change?

-As you age, your voice deepens -During puberty hormones are released that cause the vocal chords to lengthen and thicken -Testosterone causes the larynx males to greatly increase in size -Genetics play a small role

A cuttlefish (plus other ocean creatures) can change their color to reflect the background they are on. How does it do this? Give examples.

-Cuttlefish and other creatures that change their colors to match their enivornment have multiple layers of chromatophores on their skin -When the chromatophores are activated various colors and textures "mix" together cause the skin to change -There may also be sensors on the skin which automatically pick up information from the environment

How do bats and other creatures use echolocation to search for food? What mechanism in their body produced the wave and how does it work?

-Echolocation is the process of using sound to locate objects -The sound is reflected off the object (prey) and picked up by the bats -The returning energy includes info about size, distance, direction, surface texture, type of material, etc of the object

What is fluorescence and phosphorescence? What is happening in the atom to cause it? How is light produced in an atom?

-Fluorescence requires the excited electron to decay and in doing so gives off UV light. When the original source is turned off then the light goes out. No afterglow -Phosphorescence is the same type of process only the decay step is really two steps with the first taking some time. Therefore, there is a delay in the light seen. In this case there is an afterglow -Visible light is involved as well in both processes

Fire Rainbows:

-Formed when light enters a horizontally-orientated ice crystals that's flat and hexagonal -It forms a large diameter arch of which we can only see a small portion. Therefore, the Fire Rainbows look very flat and colorful -They can only be seen during certain times of the year and from newly-formed clouds -They tend to be seen at latitudes greater than 58 degrees

Why are blue jays blue?

-He is blue for the same reason the sky is blue, because of the reflection of light -The feathers on a Blue Jay are transparent however they have a different structure. When the light hits the feathers the blue light is scattered back. the rest of the colors are absorbed -Produced from scattering

Night Goggles:

-Let you see better in the dark by "boosting" vision -The object must be emitting some light in the visible part of the spectrum, goggles intensifier the light available so that image is visible -Light enters the lens and excited the electrons. That energy is released through decay which makes the images appear much bigger than the original. -The green tint is due to phosphors on the screen and make it easier for the eye to see

What are the different parts of a shadow and how are they formed? What causes a Solar Eclipse? A Lunar Eclipse?

-Lunar= Moon is covered, moon has to be in a full position -Solar= Sun is covered, the moon has to be in a new position -The sun is 400X larger than the Moon and is 400X further away, they seem to have the same angular diameter

What are the Northern and Southern Lights? How are they produced? Why do they have the different shapes and colors they do?

-Northern and Southern Lights are produced from interactions between the Earth's Magnetic Field and the Solar Winds from sun -Colors are indication of the specific chemical and its energy

What types of waves are produced in an earthquake? What kind of damage can occur and why? What can be done to minimize the damage? How can we use earthquake waves to explore the center of the Earth?

-Primary waves are the fastest and move through the crust like sound waves move through air. They are more of a push/pull wave -Primary waves are longitudinal waves -Secondary or Shear waves don't move -Surface waves do the most damage

Earthquake Lights:

-Research is ongoing but there have been several hypothesis proposed -Disruption of the Earth's magnetic field by tectonic stress -Quartz-bearing rocks produce voltages when compressed in a certain way -Grinding rock can cause stress in deep in the Earths crust which in some types of rocks can break apart pairs of negatively-charged oxygen atoms -May appear before, after or during an Earthquake -Can be similarly shaped like an aurora -Usually have a white to bluish hue bu may have a wide color spectrum -Can last anywhere from a few seconds up to 10 minutes

Why are leaves green? What causes them to change color in the fall and why do they have the color they do?

-The 3 types of pigments present in the leaves of plants -These pigments or organic molecules are what determine the colors of leaves -It depends upon the production (or lack of) as to the actual color we see -Leaves appear green because of the chlorophyll they contain -Chlorophyll is a chemical substance that absorbs, reflects, and transmits visible light -Chlorophyll absorbs mostly red and blue light energy which is used to power the cells -Chlorophyll absorbs mostly red and blue light energy which is used to power the cells -The green light/energy is reflected back from the leaves and is the color we see

What color is the Sun as we see it on Earth? Is that the same color the astronauts see from the International Space Station? What are the colors of the planets?

-The Sun as seen from outside the Earth's atmosphere appears to be white -When we see it from the surface of the Earth it appears a whitish/yellow color -We see that color because the average of all the colors left after some of the blue/violet colors have been scattered out

What is a green flash and how is it formed? What is Venus's Belt? How does it form and when can you see it? What is "the Glory" relative to light and how is it formed? When can you see it and how?

-The atmosophere acts as a prism and refracts the light of the Sun as it's going down -The setting Sun's light is broken down into its component colors. Because of the great speed of the Sun however, we usually only see "one" sun -If the atmosphere is very clear then you can see a Green/Violet flash

Why is the sky bluer after a storm? Why are storm clouds dark? How and under what conditions do clouds change color?

-The atmosphere is made up of nitrogen and oxygen, water, dust, etc. all contributing to give the color sky we see -After a storm almost everything has been "washed" out of the sky therefore the sky looks more blue after a storm -Humidity can also influence how blue the sky appears- the more water in the atmosphere the light the blue of the sky. The drier the atmosphere the deeper the blue

What determines the color of a star? Why can't you see most stars during the day on Earth but the astronauts can when they are in orbit? How does the Moon shine?

-The color of a star is determined by its surface temperature -Red starts are the coolest and blue/white stars are the hottest -Color may be an indication of where the star in its evolutionary sequence

What mechanism allows us to talk? What determines the "sound" of our voice? How does your voice change as you grow up? What causes that to happen? Why does your voice sound different in a recording?

-The lungs, throat, voice box, and tongue, and lips are all used in conjunction to allow us to talk -The vocal chords stretch against larynx because of the vibration of the air -The length, tension, and size of vocal chords determine "fundamental frequency" of you voice

What are thermal scans, how are they produced and used? How do night vision goggles work?

-The retina of the eye contains rods and cones -Cones are responsible for vision when there are high levels and allows a person to see in color -Rods are responsible for vision when there's small amount of light and can see black and wight. There are 20X more rodes

How do eagles and other bird of prey see so well? Give examples.

-They see farther and perceive more colors -Objects in their line of sight appear magnified and everything is brightly colored -They have very large pupils -They have millions of light sensitive cells on their retina -They have two centers of focus which allows them to see forward and to the side at the same time -They have an inner eyelid that closer every 2 to 4 seconds

Thermal Scans:

-Use heat rather than light to create an image -All objects have a certain temperature based on their internal energy. They will have a "heat signature" that's determined by the thermal energy or infrared radiation given off -A thermal scanner will convert the IR energy waves into visible light, producing an image

Elephants and whales can locate and communicate with each other over very long distances. How does that work and what produces the sound. What is the frequency range of their speech?

-Whales and elephants use a low frequency sound which can travel very well over long distances (miles) -In some cases the sound energy is below the human threshold

What is the color of water? Why does the ocean sometime appear blue, green, or red?

-What has a slight bluish colors that is there because of absorption and scattering -Water absorbs light in the lower, less energetic part of the spectrum. What's left is scattered and appears as a light turquoise color -The deeper the water, the more blue it becomes -Water can appear to be a variety of colors due to the material dissolved or suspended in ti; pressure; temperature; sunlight; etc.

Why does your voice sound different in a recording?

1) Vibrating air waves hit your ear drum which converted into the sound energy that you hear. This includes every sound made be external sources 2) Your vocal chords causes vibrations in your skull, which is what you hear as your voice. The pitch is lower because of the transmission through your skull. Recording tend to sound higher due to lack of false bass component

Why is the sky blue? Why is the sky bluer the higher up you go? What color is the sky on Mars? Venus? Titan? Why?

Properties= Reflection, Refraction, and Scattering -The sky is blue because of Scattering -Scattering is a form of reflection in that the light bounces off molecules in the atmosphere -The small molecules scatter the shorter wavelengths of light better => violet and blue -The further you go into the upper atmosphere the small number of molecules. Therefore, the sky will appear a darker blue/deep violet gradually fading into black

How is a rainbow formed? Why are there two rainbows seen at times? How does the second one form?

Properties= reflection and refraction -Formed by a water drop -A double rainbow is formed from a second reflection in the water drop -Most of the time it's over the ocean -You only see half of the rainbow because it runs into the Earth

What are Earthquake Lights? Light Pillars? Fire Rainbows? Each is a weather phenomenon that deals with light. How are they formed and what do they look like?

Properties= reflection, refraction, and interference

What color is the fur on a polar bear? How does that help the bear stay warm? Why is a blue jay blue - how does it get its color? What causes the vibrant colors of feathers in birds?

Property= reflection -The polar bear's fur is colorless -The fur on a polar bear is a thin tube that's transparent and hollow, it acts like a fiber optics tub -Light from the Sun is conducted down the tube to the skin, which is black. since black absorbs energy very well the bear keeps warm. -In addition there is usually a thick layer of fat right under the skin

How is a halo around the Moon/Sun formed? What does it usually forecast and what conditions are needed for it to be seen?

Property= refraction -A halo around the Moon or Sun is caused by the refraction of light through the ice crystals in cirrus clouds -Usually there's no color associated with the Moon because it isn't bright enough for the light to stimulate the cones in your eye. -There's usually some color with halos around the Sun

Why does the Sun/Moon appear to be highly colored when it is rising or setting? What happens to the color as they continue to rise? Same question as to size - why do they seem so much bigger when you see them rise or set?

Property= scattering, reflection, and refraction -The greater the amount of atmosphere the light goes through, the greater the scattering -Very little atmosphere => white Lots of atmosphere => red -The great the motion of the atmosphere, the greater the scattering

A singer can cause a glass to shatter with their voice. How does this happen and why? What other examples of this mechanism exist?

Resonance: -Every object has its own natural vibrational mode or frequency. Therefore, there's a specific energy related to vibrational mode -If the vibrational mode is increased then the energy used increases as well -If the energy becomes too great for the structure of the object, then the object will break

Color of the sky on Titan=

green/blue

Color of the sky on Mars=

red

Color of the Sky on Venus=

yellowish/white