UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
375 questions in the Category: optics/light.

Click Here to return to the search form.

1: Why are some people color blind?
2: Why is the sky blue? Why are different flowers of different colors?
3: Do molecules have color?
4: Why do I see green color spots after I stare at red color for a long time?
5: Why can't light go around corners? And why can sound?
6: How does an L.E.D.(Light Emitting Diode) work? Why does light appear?
7: What makes the sky blue?
8: Lets just say you are in a car that is traveling at the speed of light....if you turn on your head lights, will anything happen?
9: If the sun's light peaks in the green, why do plants prefer to reflect green light (giving them their green color)? And in particular why do they prefer to absorb red light and with that not efficiently utilizing the sun's radiation?
10: This general Chemistry class is just starting off and we wanted to exercise our curiosity by asking questions. Can you please tell us why do we see all of the different colors we see? Someone told me that it is because of chromophores and I was wondering if that was true. Thank you very much.
11: Why is it that you can see yourself in a mirror with every accurate little detail?
12: What causes the parallel lines of light and shadow on the ceiling above my bedroom window, in the morning when the curtains are still closed?
The lines extend beyond the ends of the window, and are very numerous and of varying in width and grayness. Covering any area of the window merely reduces the intensity overall.

13: I work in a grocery store and they just installed barcode scanners. The problem is that the scanner is fronting us, the cashiers, directly at the level of our reproductive organs. Is there a risk or danger to be "scanned" all day around such a sensitive area? Thank you Xavier Krieger
14: Hi! I just had a quick question on the topic of optics. I did an experiment wher I shone a flashlight's beam through several sized holes at an object. I noticed that the larger the light source, the smaller the object's umbra was and the larger the penumbra was. Why was that? And for a smaller source of light, the object's umbra was larger and the penumbra was smaller. Why was that? Thanks!
15: How can you see your bone in an x- ray? How does it show up?
16: How do you guys look at the sun directly? What do you use for?
17: Things move slower in the time dimension as they move faster in space dimensions. So, does light move in time at all since it is moving at the speed of light?
18: Why do some things reflect your image (like metall or dark window glass) and other things do not (like wood, concrete, paper)?
19: I understand why and how objects reflect, but why does it show perfect images of the surroundings? An example- "the ocean surface shows the clouds above." Why is that?
20: What does food coloring do to plants?
21: How do you measure the moon from the distance?
22: How is solar power converted to electricity? It's just light right?
23: What is the famous "green flash" all about at sunset?
24: I am a student at La Colina working on my science project. I have a few questions about the topic "Triboluminescence" with Lifesavers and other candies. What are the elements and compounds involved in causing the spark? Does friction play a part in causing triboluminescence? Is the reaction exothermic or just releasing light? Can the reaction be done using a screwdriver(or other hard surface to cause a spark)? If you can respond to all of these questions that would be great.
25: Which colors absorb the most heat? Why is this? Does a bright color like yellow absorb a lot of heat?
26: I am actually a parent asking this question. My daughter's class is studying space and we went to the astronomy day at the museum last week. I personally have an interest in buying a telescope. I found what appears to be a quality scope at a good price, but is it a good enough scope? Which is a better deal? A 6" reflector telescope with an aluminum stand for $185 or a 8" reflector telescope with a steel stand and motor ra for $485? Is the 2" difference worth the extra $300?
Thank you

27: Thank you for the reply.... The telescopes I'm looking at are on ebay. They are both sold by the same company and are the same brand of telescope. They are Newtonian, Baytronix short tube reflector scopes. If you have the time / energy you can easily find them by logging on to ebay and search for telescope. Each scope has the list of specs and someone like you would know the meaning, but its foreign to me. When I went to their other items for sale I found the motor for $50 (if it is the same one) so perhaps the money is in the larger mirror like you said. Is the larger field just to make it easier to find your target? It appears the difference in magnifiication is 1000 vs 1400. Is that a lot?
28: Can food coloring dye contact lenses? And if it works,can it be toxic to eyes?
29: How does a prism reflect light into the colors of the rainbow? I know it uses refraction, but how is it actually refracting the light through the prism and seperating the colors from the white light?
30: If a particle with rest-mass were to, in theory, travel at the speed of light ,would its mass actually be infinite, or just very, very, very, large, just like it would supposedly take an infinite amount of energy to accelerate the particle to the speed of light in the first place? How can you calculate this?
31: Light, like gravity, is very efficient at bending the spacetime fabric. How powerful of a beam, or sphere of light would you need to have to bend the spacetime fabric into a 1g well? Actually, what I am really trying to say is: Is there a formula to figure out such a problem like the one above?
32: Since light is electromagnetic radiation, would it be possible to send magnetic charges on a beam of light, or some other way using light?
33: Why cant information be sent faster than light? Couldn't you just increase a photon's speed by using some sort of electrical or magnetic fields, and send the information that way?
34: By how much is a ray of light bent and slowed down when it passes by the earth at certian angles and distances?
35: I know how long it takes for light to reach us but how long does it take for heat to reach earth from the sun?
36: Why the heat from the Sun can enter the atmosphere easier than it can get off from it?
37: I am participating in the Senior Project at my school and my topic is about the incandescent vs. fluorescent light and how it affects theatre in the future. I hope my mentor can help me with things like problem solving, job shadowing, interviewing techniques, and troubleshooting.
38: Thanks for answering my questions! How would it be possible to transfer energy wirelessly? Energy such as kinetic energy or gravitational energy? Any information would be helpful, I really hope you can tell me how or where I can get information to be able to transfer those types of energies, or in what types of situations that could be done.
39: At which wavelength does maximum Photosynthesis take place?
40: If light reflects off an object and that is the color that we see, how does a projector (like an LCD projector) send light to a screen to bounce back to our eyes?
41: I have heard that the speed of light is absolute. But, what about if you are (theoretically) traveling at the speed of light, will light be going the speed of light faster than that? Why is the speed of light absolute, how does it work out?
42: How can light pass through transparent solids like glass and clear plastic?
43: How do all the electrons absorb the light and then release the the light in the same direction? Is that a characteristic of the materials?

Thanks so much,

44: what is the adaptive value of algae having different pigments?
45: My class was reading a story on the sun and they told us an exact temperature of the sun. How did they get the temperature of the sun if it is to hot to even get near it?
46: I was wondering why images look magnified when you look at them through water?
47: Wikipedia says NF3 absorbs 17,000 times more IR energy than CO2, so why? Is it about different vibrational modes again? Thanks
48: What is dark matter and how does it react to common materials?
49: What is nuclear winter?
50: Hypothetically speaking, if you were in a car going at the speed of light, what would happen if you turned your headlights on.
51: How can information travel through copper and glass cables without any of the information being damaged, and still all end up at its destination as an exact replica of the original copy.
52: How does LCD work in television sets?
53: What type of honey bees live in my area? What color are they most attracted to? Can they see color?
54: Can sharks see color?
55: If absolute zero is the term for when all molecular movement stops, what is the term (if there is one) for when molecules move at the absolute fastest they can?
56: How do fluorescent lamps make so much light without a lot of heat?
57: Why does a wet spot look darker?
58: I am confused about how light works, and "invisible light" works. How do we not see certain types of light? Thanks!! -Samantha
59: Which is the color of light not reflected by chlorophyll?
60: What is color? Why are things the color that they are?
61: Hi! Lets say that a rocket is in deep space, and the rocket experiences the gravitational attraction of a very massive star (or some other body). The star begins to accelerate the rocket toward it due to its high gravity. If the rocket continues to accelerate due to the star's gravity over a long period of time, wouldnt it eventually be moving faster than light without needing infinite energy to get it moving at that speed? (gravity does all the work)
62: How do you calculate the speed of an object according to the theory of relativity?
63: How would you measure Ultra Violet light on green algae? What units of measurements would you use for measuring Ultra Violet light?

I am teaching my chemistry students about electron transitions in an atom by absorbing or emitting a photon of light. Are there other mechanisms for exciting an electron that do not involve a photon?

My particular question has to do with the burning of metal salts to produce a characteristic spectra. It is clear from the line spectra that we are seeing a quantum effect of the electrons transitioning between levels. What is the mechanism for the electron excitation?


65: Hi! If one was to bounce a laser beam, or even individual electrons off of two or more mirrors (sort of like a light clock) would the particles in the beam of light or the electrons ever slow down and stop? (assume the mechanism is in a vacuum) Or would they just continue bouncing forever? Thanks for your help!
66: Hi! Do "light clocks" (the things that bounce a particle of light between two or more mirrors - has to do with relativity) really exist? Would it be possible to make a "light clock"? Thank you for your help!
67: Hi! When looking at how the "death star" works (from the Star Wars movies) it becomes clear that shooting multiple lasers together at one point to create one beam of energy would be impossible without some sort of lens. (If you take a look at how the "superlaser" works on the death star, the beams of light would not create one beam, instead they would intersect and continue going off on their own path without any change in direction.) Some sort of lens would be needed to direct the multiple lasers into one beam, what kind of lens would do that? Would a double-concave lens placed at where the lasers intersect direct the multiple lasers in a way as to form a single beam? Thank you for your help!
68: Hello! I have recently been working on a paper that suggests a way of disproving the first postulate of the theory of relativity, as well as the equivalence principle. The mechanism that I am proposing is as follows: Imagine that you are in a large box. You don't know if you are moving at constant velocity or if you are at rest. According to the first postulate of relativity, it is impossible to figure out if you are moving uniformly or if you are at rest. Regardless, you try to build a mechanism of distinguishing between constant motion and rest. You design the following mechanism: Knowing that the speed of light is constant, you shoot a photon from one wall of your box to the other, and measure the time it took the photon to reach the second wall. You calculate how long the trip should take (at rest) and how much longer it should take if your box had some forward velocity. Then you compare your calculations to your observations. You assume it should take longer for light to reach the second wall if your box is moving because the speed of light is a constant and because of some principles of simultaneity of relativity. The theory is, if the box is moving, light (being like an arrow - and its speed independent of the speed of the box) would take longer to hit the target (the second wall) because it moves forward during the time light is travelling to hit it. So light catches up to hit it at a time slightly longer than it would take if the "target" did not move. From that info it becomes easy to distinguish if you are at rest or moving; and at what speed you may be moving. Of course, this is relative to the speed of light, but light speed is a universal constant, so I dont think that poses a problem to the theory. Is the assumption that you make correct? Would this be a way in which one could disprove the first postulate of the theory of relativity, as well as the equivalence principle? Can I excpect to receive a Nobel prize anytime soon?! :-) :-) I'd love to hear your opinion. And if it turns out that I'm correct, I'd be glad to send you a copy of my paper as soon as I complete it, for review. If I'm not correct, then at least I'll understand relativity better. Talk to you soon!
69: Hi! In my first attempt to disprove the first postulate of the theory of relativity, I may be incorrect because distances and time change as an object moves. Because of this, it may not be possible for an observer in an inertial frame of reference to detect if they are at rest or moving uniformly in this way. But I do have another way in mind that I would like to ask you guys about, its based on some principles of simultaneity: If an observer is in a box (without knowing that it is moving or at rest) and they have one light bulb on a wall of the box and another light bulb on a second wall (facing each other) The observer turns on both lights at the same time. Wouldnt the observer be able to detect if they were moving or at rest due to when they percieve the light to reach them? If they are moving, light from one light bulb would reach them first, but if they were not moving, light from both light bulbs would reach them at the same time. Is this true? Could this method be implemented in disproving einsteins first postulate? Thank you for your help, I hope to hear from you guys soon!
70: Why do some candies (like wintergreen lifesavers) spark when chewed?

This is more of a maths question than a science question, but I'll ask here anyway, since I doubt it'll be covered at a High School level:

Why, precisely, is e(pi * i) + 1 = 0 ? (I'm aware that e(pi*x) = sin x + cos x, but I'm not sure why that is the case, either.)

72: Does Argon turn sky blue or lavender when electricty is ran through it? Thanks
73: We are doing art with color paper and bleach. The students want to know why the bleach makes the paper white. Can you explain the chemical reaction behind? Thank you very much.
74: Hi! Thanks for answering my previous questions. Considering the fact that a particle moving at (.999)c could be seen as moving at a speed greater than c if observed on the hypotenuse (but contains no information), could not you create a situation where that particle does contain information? This is sort of based on the tachyon antitelephone example: Let's assume that you have one person at the ends of the hypotenuse, person one sends a signal at c (or vc along the hypotenuse, the reply could cover "more" distance in "less" time and appear to go against causality. Is this true? Would such a set-up go against causality (to one extent or the other)? Sorry for the long question, but thank you so much for your help!!
75: Are there any colors that human beings can not see?
76: I have a simple question regarding basic thought experiments to do with special relativity (which we just started in school). The thought experiment our class went through to explain time dilation was of a train travelling at relativistic speeds with a pulse of light moving up and down in a straight line within the train (reflecting off a mirror on the roof). Relative to an outside stationary observer, the light pulse is moving over a greater distance than just up and down (it is travelling the hypotenuse of a right angled triangle because of the train's motion on the x-direction), but because light travels at 'c' in every reference frame, the pulse must still travel at the same speed 'c' relative to the outside observer. Hence, because it travels a greater distance with the same speed, it must take longer to do so and hence time will appear to be running slower within the train - relative to the man outside. I understand the logic behind this however it seems to me that the thought experiment could be turned on its head by changing the direction the pulse is fired at. Say for example that instead of straight up and down, the light pulse is shot in a direction opposite to that of the trains motion, with an x-component equal to the motion of the train (i.e. if the train is travelling right at 0.5 'c', then the light pulse is fired left with an x-component of 0.5 'c'). If this were the case, the stationary man outside would now see the pulse travelling straight up and down relative to him and therefore see the pulse travelling a smaller distance. because the pulse still travels at 'c' relative to the outside observer he will now see the pulse travelling a smaller distance with the same speed, i.e. in a quicker time. To the outside observer, time now looks as if it has sped up inside the train (but of course this must be wrong because 'time dilation' says that time will always slow down for a stationary observer looking into a fast moving reference frame) I am wondering what exactly is wrong with this thought experiment. it uses the same logic as the original thought experiment (which was taught in my syllabus) but achieves the opposite result, it seems to prove time 'contraction' rather than time dilation. Help would be greatly appreciated.
77: Why is it that a lightbulb requires a filament, or a different process, (depending on the type of lightbulb) while a radio transmitter uses an antennae? They are both photons, no?
78: How does a TV send signals from the studio to my living room? Does it break down the picture into microscopic particles?

Hello! Is it possible to convert from the time dilation effects caused by velocity to the time dilation effects caused by gravity? In other words, if one calculates the time dilation effect caused by a given velocity, how can one calculate the gravity needed to create that same effect using acceleration? I dont know if I am explaining this in a way that makes total sense, but I would like to know how to convert time dilation values due to velocity to time dilation values due to gravity. I know that acceleration is velocity changing over time so I assume any conversion would have to take that into consideration, I am just not sure how to due that using the time dilation formulas that I have (for velocity and gravity). Thank you for your help!

80: Hello, I have a question regarding wormholes and quantum entanglement. I know that, theoretically, if one was to take two ends of a wormhole and keep one stationary while one moves around, it would be possible to travel back in time. Could this be duplicated practically by using entangled particles - due to the fact that they are connected instantly much like the two ends of a wormhole? In this experiment, one would keep one particle stationary while moving the other one in a particle accelerator or something like that, to observe the time dilation effects between them (hopefully resulting in some form of backwards time travel effects, like the case with the wormholes). What is your opinion on this? And is it right to compare wormholes to entangled particles because of their similar characteristics (with regard to connecting different points in space - or different particles separated by space) instantly? Thank you for your help!
81: What colors of light are used in land plant photosynthesis?
82: How do Auroras(Artic Lights)form?
83: Why is the sky blue?
84: Why can people see more clearly when they squint their eyes?
85: What is the effect of light on the color of grass leaves (as a phenotype)? What is the effect on the color in absence of light?
86: Can absolute zero stop time?
87: Is there another way to stop time than traveling at light speed? I learned that mass can't go at light speed unless we have infinite energy (which we don't). If there are other ways of stopping time, won't it be so much easier?
88: How do photons travel so fast? Is there a way to stop them?
89: Does temperature affect the amount of energy a solar panel receives?
90: Does color really affect the plants growth?
91: Does your eye color affect your eyesight? If so, I have hazel eyes, would I see better or worse than others? I'm just curious.
92: How does age affect how quick one sees an illusion and how does personal relevance affect how quick one sees an illusion?
93: If light is coming from a bunch of diffent angles how will the plant grow?
94: How does reflection happen?
95: If heat is simply the movement of molecules, then how to infrared cameras, which capture infrared light, manage to see heat? Or phrased differently: How does heat give off infrared?
96: How does light color affect plant growth?

What is the fastest and most reliable way to make large sheets of Graphene?
Is Graphene entirely transparent to light?
If you have multiple layers of Graphene would this absorb more light?

Thank you

98: Hello, I use a laser to test whether a mixture is heter or homogeneous. I have always used a red laser. This year I have a green laser and the added power is giving me different results. For example, Sunlight dish soap will appear homogeneous with the red laser, but heterogeneous with the green laser. Can you explain this? Thanks.
99: We want to know which is faster: electricity or light?
100: We were studying about different kind of lenses. How can contact lenses help people see better, when they are on top of your eyes?
101: What is light and why does it travel so fast?
102: I would like to know why water's blue in the ocean and clear in a cup? My teacher lives in by the beach and the color are green, red, gray, black at night. My friend Valerie said that it looks blue because of the sun reflection. What is the waters real color?
103: We want to know is blood blue or red? It looks blue in the inside and on the outside it is red.
104: What happens to light in a black hole? Is there an end to a black hole?
105: If you built a car that could travel at the speed of light and you turned on your headlights, what would happen and what would we see?
106: What are the black dots you see when you close your eyes?
107: Why is the sky blue when you look up, but a bluish-white on the horizon?
108: Why can't we see stars in the day time like we do at night?
109: I was wondering if light have mass or weight? If so, how is it measured?
110: I was wondering how ultrasound works. Ive seen it in T.V. and it looks really weird. When I saw it all I see is something moving, How can you guys tell where the arms and the legs are? Is there a better method for looking inside the stomach without hurting the baby?
111: I have a problem, and I need your help to solve it. My teacher took away my laser when I shined it at another student in class, because he said it's bad for our eyes. He said I could get it back if I could find out WHY its bad for our eyes. Does it really hurt you eyes? If it does, why?ps. Please write back fast because the laser isn't mine!
112: Why is it when I turn on the stove the flame comes out blue? Also sometimes it gets orange on the top? So why's that?
113: We are trying to find out how cameras work. We found information about why cameras need light,but wonder what is the difference between video film and rolled film. We also were wondering how the pictures get on the film roll, how much light is needed to take a picture,and what makes the film develop. Finally, our teacher says that digital cameras like one he has dont use film. How do we find out more about the differences????
114: Why cant our eye and brain process certain parts of the electromagnetic spectrum? We know that we can see the visible part, and that other animals can process infrared, for instance. What is it that makes our brains different in this respect?
115: Why do we need lasers? What do we use lasers for? How do you build lasers? Who invented lasers? How big and powerful can lasers be? Why/how do lasers travel over long distances? Are all lasers red? What does the color of the laser mean?Why are lasers dangerous?
116: Is there any correlation between the index of refraction of a material and the density? It seems there might be until I consider the atomic structure, etc.
117: Why are clouds gray?
118: Why is the sun so hot and bright?
119: Why is space black?
120: Why do stars twinkle?
121: We've heard that ideas of the curvature of the earth come up when a ship is seen slowly disappearing down the horizon. How can we calculate the distance of the ship?
122: Why do the sun and moon look bigger when seen on the horizon than they do when high in the sky?
123: How do different color filters affect plant growth?
124: Why is the ocean blue? My guess is that shorter wavelength blue light is refracted more by tiny particles. Or, is blue light absorbed and then re- emitted more commonly than higher wavelengths by certain molecules.Are these two interpretations of the same process? Please provide as complicated of an answer as you wish; the more explanatory, the better.
125: How and why do glow sticks glow?
126: Why are red stars cooler than white stars? I thought red things were hot.
127: Measuring light years:How is the speed of light actually determined? How could you measure something that's speed is inconceivable to us? If we went somewhere else...say a star and watched the light from the Earth reach us, would it be like watching a movie?
128: What would happen to me if I went through a black hole? Would I end up in a different universe?
129: How do we know how stuff really is out there if it's too far out to explore and would take years to get to?
130: How do CDs work?
131: How do Ultraviolet Detecting Beads work? What's the chemistry behind them? UV detecting beads contain a pigment which changes color when exposed to UV light. These beads are sold by Educational Innovations Inc. Their web site is: www.teachersource.com
132: Why is milk white?
133: How do glowing algae (dinoflagellates) chemically create their light?
134: How do flowers make their color? How come that the same flower - like lupines for example - can have different colors (pink, blue, red)?
135: This question is not for school. I wanted to now sense you can't look at solar eclipses directly. Can you use sun glasses, 3d glasses or a cell phone to look at them without hurting your eye?
136: When does Argon gas go into the "lasing" phase? What is the typical wavelength(s)of Argon gas during lasing? How much energy at which tempo is needed for lasing?
137: Do you think we will ever be able to harness and/or contain the energy of antimatter for usage in most areas in a safe manner?
138: How energy generated by chemical reactions can be converted into light energy in terms of the behavior of electrons? Does a compound that emits red light would require more energy than a compound that emits a violet light?
139: Hi,I have query related to UV index. If there is an UV index of 15 affecting a room made of clear glass, no special coating, no lamination, just simple breakable glass of thickness 3mm, how much UV will pass through and how much will be blocked by this 3mm thick plain, clear, no laminated/coated glass?
140: Can a black hole be created by the Earth's pollution and our radiation?
141: Why light reflects off mirrors?
142: Why people living in India and UK have different eye color ?
143: Does the color blue effect plant growth?

We are doing the science fair at our school and I need to conduct an interview with a scientist by e-mail. The question of my project is: Which color light transmits the most energy and heat?

In the interview, I would like to ask questions like this:

Information about you, like name, email, career field/studies.
What knowledge do you have on energy and the color spectrum?
What could I do to improve this project or expand from it?
What are some similar things that you work with that could help me better understand my project?
Any ideas that could help me will be great.

145: If we were to communicate with an astronaut on space, would there be a delay? If so, how late would that communication be? And how would they communicate with us?
146: How do colors affect the light for a plant to grow?
147: How does the light affect the growth of plants?
148: How does magnetism affect Earth?
149: How does color affect plant growth?
150: Why has x-ray been detected to pass through a black hole?

Hi! For my science fair project I'm doing an experimenting plant gravitropism, by growing three bean plants upside down, and three right side up. I have some questions for you to please answer:

1. For the upside down bean plants, I just put the seed in normally, however it still grew upwards. The roots came out of the bottom of the fiber seed starter pots, and the shoots burst through the pot and grew upwards! I expected the plant grow down, and then curve up.
2. What would have happened if the pot was clay? Would the shoot have turned around when it reached the top, and grow out the bottom?
3. What should I have done if I do the experiment again?
4. I know about negative and positive geotropism, and I now feel bad for having expected it to grow down and then up! Thanks so much!- Natasha

152: What would happen to a particle if we accelerated it to the speed of light? Will the particle fade or will it turn into energy? PS: I know we can't accelerate particles to the speed of light, but I'm just asking "what if?"
153: How does heat transfer?
154: What happens when Magnesium burns?
155: Do different colored lights affect how images are seen or interpreted? Can colors show help people visualize images? Does sexuality cause people to like or dislike a color? What effect does environmental color have on someone's mood?
156: What is a black hole?
157: What is an optical illusion?
158: Why do zebras have stripes?
159: Which color does absorb most heat in color pans?
160: If you go faster than the speed of light will you go back in time?
161: Does energy of color affect the growth of plants? Why? What range of color energy is best for the growth of young plants?
162: How do pigments absorb and reflect different wave lengths of light?
163: If humans receive biochemical damage from solar radiation what can happen to them?
164: What will happen if a human would go through a black hole, what would I see?
165: If the universe is expanding, how is that galaxies can collide?
166: How does light affect plant growth?
167: Were do non photosynthetic plants get their energy from, and how do they do it?
168: Can a plant stay alive without light?
169: How do you make a light bulb light up with a battery, a negative and a positive wire, and what kind of battery would you use?
170: Why is the sun so bright and hot?What instruments do scientists use to study the sun?How big can a solar flare get?
171: When you put water on clothing, why does the color look strong?
172: Why do black objects absorb more heat (light) than lighter colored objects? What do wavelengths have to do with it?
173: What is melanin?
174: Why are trees and plants green in color?
175: How can I check if I see red color for example the same ways as you would see it?
176: Does different color light change the color of a plants petals or the growth?
177: Which colors absorb the most heat? Why is this? Does a bright color like yellow absorb a lot of heat?
178: Why do mirrors reflect?
179: Is it possible to refill the holes of ozone? Can a new compound be discovered which could act as a protective covering for earth from harmful rays of the sun? If this is possible, please tell me the elements which are protective in function to UV rays . Can you send me related web sites where I could learn more?
180: Before I start I just want to say thank you for this web site, I love it. I learned that plants need sunlight, why are there some plants which do not need sun light, and why?
181: Does the amount or intensity of light affect a plant's phenotype?
182: How fast or slow do coral reefs grow?
183: We know that the sun is not the biggest star, but is it the hottest star?-Thanks.
184: If black color absorbs the most heat, then why is plant life mostly green?
185: What is color?
186: Why no photosynthesis takes place in blue color light, and why minimum photosynthesis takes place in green color light, and Why the rate of photosynthesis is maximum in red color light?
187: Why does lightening occur in rainy times?
188: How can light be matter or not?
189: Why does a rainbow occur?
190: Some defenders of incandescent bulbs claim that the waste heat generated will lessen their heating bill. If 90% or 90w of an 100w incandescent bulb generates x amount of heat how much heat could a 90w Nichrome heater produce?
191: What effect does color have on heat?
192: If black absorbs the most heat, then why is most plant life green?
193: Which stars are cooler red or blue?
194: If light is non-special, then it has no volume or mass. But how can light exist in the third dimension without volume or mass?
195: Why light is not matter?
196: Why can we see colors? And why can we see light?

Hi, I have a question related to an already posted topic:"Why is tungsten used for filaments in light bulbs when nichrome's resistivity is so much higher?


I understood, after reading your answers, the importance of the high melting point of the material of the filament. In order to get visible electromagnetic waves (i.e. light), we need the material to be at a certain temperature and it is tungsten that can reach that temperature without melting. However I do\'t understand another thing. The power supply is given by a constant VOLTAGE supply, say 120 V (not constant current). Ohm's Law states V=I*R And Joule's effect states Q=I2R By combining these two equations, we get that Q=V2/R. Then, why we would want to have a material with a high resistivity? If V is fixed, then Q actually DECREASES with the higher R. The former equation, I2.R, might be confusing but the thing is that, as said before, I is not fixed, but V is.

So by increasing R, we are decreasing I and that's why I2.R will decrease. In conclusion, I understand that tungsten is a good material because of many of its properties, as the high melting point. But, why to increase the resistance of the filament by increasing its length and decreasing its cross-section since it seems to me that it should be the other way round? Were am I making the mistake? Sincerely

198: Why plants use only CO2 for photosynthesis, and why not any other gas with carbon atom?
199: Light has many sources. The greatest is the sun. Are scientists using other light from other stars to produce energy?
200: Who discovered lighting?
201: Why are black colors the best absorber of light/heat?
202: Can you tell me how bright is the sun?
203: How does it work the test to discover the focal length of a pair of glasses?
204: Does the artificial light effect the pigment of the goldfish? If so, how long do you thing it will take to the goldfish to change color?
205: What are things that are alive, but display characteristics of non-living things?
206: How come you don't see everything blue if your eyes are blue?
207: What makes skies blue?
208: What causes a spark? Has it something to do with the event when a positive and a negative charge meet?
209: What is the difference between a spark and Triboluminescence?
210: Does a relationship exist between a person's eye color and his/her ability to identify colors in dim light?
211: How do people with 4 cones in their eyes see color differently than most people who have three cones? Why do they see so many more colors? How do cones work?
212: How does Photosynthesis affect other organisms?

I 'm aware when plants are not in the light they respire just as we do. I also know the products of photosynthesis are sugar and oxygen. My questions are:
How do plants get energy when they are in the light if photosynthesis produces no ATP? Do plants always have to respire with the sugar produced from photosynthesis? Or is there some energy made from photosynthesis and if so in what form?

214: I have a question on my big campus (San Diego campus)that says "there is something in the leaves that uses this energy to break apart the hydrogen and oxygen atoms. "This energy" relating to light energy. Can someone help me to know what is the "something"?
215: Why do green pigments reflect green light?
216: Why does green not absorb red, but red absorbs green?
217: Aurora Borealis are only formed in Northern/Southern latitudes, why is that? And what will happen if we, places near the equator, which is a bit lower, see those?
218: How can I get electricity started with just a battery, two wires, and a light bulb?
219: Are stars hot or cold?
220: Why are colors the color that they are?
221: Does the color of your eyes change how you see colors in dim lighting? And how does it work?
222: Is there time travel in space?
223: How do microwaves work?
224: Why is purple the best light bulb color to grow plants?
225: Hi again, we are studying light energy and my question is why light does not shine through aluminum?

Hi sorry to bother you, I am contacting you after reading this article on your site:

click here

I was hoping that you would able to answer a few quick questions I have about a project I am thinking about doing for the BT young scientist.

1) Do different spectra of light effect the growth of plants differently? (Ignoring green)

2) Do specific combinations of light i.e. red, yellow and blue of an equal intensity to solar light effect plants' growth?

3)Does the effectiveness of the light on photosynthesis vary throughout the day? If so do different spectra affect this?

The above questions are to aid in setting a baseline for experiments, as I haven't been able to find any definitive proof online.

Thank you for your time,
227: Does the amount of water change the color of the grass?
228: How does gold get its color?
229: What is the difference between a black hole and a worm hole?
230: I performed an experiment using colors to transfer heat form a light bulb to water. Red heated the water the most and purple the least in the experiment, even though purple should have the highest frequency/energy. Why may that be?
231: I want to construct a building with walls that have the ability to magnify its surroundings by at least 5x its size (20 diopter). Estimated wall sizes: 10ft. (h) x 42ft. (w) How big would the curvature need to be? 2. Which lens/material would work? 3. Could water be of any help? Like having to curved walls serve as a container for water. Thank You for you time. Sincerely,
232: What is the difference between the lasers used in supermarket scanners and those used in laser pens?
233: Why is there nuclear force? What is the physics behind it? I read somewhere this is due to the repulsion between protons.
234: Why is sound so important?
235: Does blue color absorb heat?
236: Do contracting objects show red shift?
237: We estimate the temperature of a star from its color. But what if the star is moving away from us at a constant rate? Then, its light would be red shifted. So, how will we know its temperature?
238: What color paper will transfer the most thermal energy?
239: How does the sun heat the Earth?
240: When light goes through a prism, why does it exit like a rainbow?
241: How does the Sun heat the Earth?
242: Why does the sun help us to live?
243: By providing artificial light during nights when the sun does not shine, will it be possible to get crops faster?
244: Does food coloring affect plants? If it does, how?
245: Is there any particle faster than light? if so, what is it? Is neutrino faster than light?
246: How earthquakes' waves provide information about the interior of the earth?
247: Does a ferret see color?
248: Is light matter?
249: Does eye color affect a person's ability to identify color in low light?
250: What is a chloroplast in a cell?
251: If plants absorb sunlight and we eat plants or other organisms who eat plants, does that mean we have a fraction of the energy of the sun in our system?
252: I've seen different drawings of human cells. They use different colors to show the different parts of the cell. My question is, what is the actual color of the inside of a cell?
253: I was wondering if there are billions of stars in the galaxy and we are inside of it, why do we see dark nights? Wouldn't the space always be bright? Thanks
254: What is the Shape of Our Universe, and where is it situated? I would also like to know what is there outside the Universe?
255: How does heat come in the atmosphere?
256: How far away are stars?
257: If light is matter, wouldn't that mean that dark rooms contain less matter than light rooms?
258: How does the level of light affect the rate of photosynthesis?
259: Why will Tungsten glow brighter than Nichrome though? I don't understand.
260: what happens during lightning?
261: Where does lightning come from?
262: I color is just certain light reflecting off a certain object(example: if something is orange, it reflects "orange" light), then is there really any color? Would the question be not "What Color is it?" but "What Type of light is being reflected?"
263: How does light travel? Why is it not stationary?
264: How does a TV remote control work?
265: What instrument did you use to gather information about stars?
266: What would the reaction be if a black hole crossed paths with another black hole of the same size?
267: Can you explain how lightning occurs in a simple way so that I can understand it?
268: Why does the moon turn red at times? And why is the sky blue? Can the sky turn into another color, and if so what color?
269: What type of material keeps liquids hot for longer time?
270: Hi, I am Ahsley,an I wanted to ask you that are real scientists this question. Why is it that people say do not wear black in summer? Please reply back, it is for my science experiment and I am putting all my effort to at least get second place, thank you.
271: When and where are lasers used?
272: Can colored light affect the way plants grow?
273: Why does Chlorophyll A and B absorb different colors better?
274: How different is the sky in the morning and the sky at night? Why we can not see the stars in the morning or in the day?
275: What effect does a prism have on white light?
276: How do plants interact with their environment? Please give me an answer.
277: How does the peacock flounder change color?
278: My group and I are doing a science project about which angle receives the most solar power and we would like some information about what you guys know and if you have anything please contact me and any detail would be fine thank you.
279: What angle from a solar panel receives the most power from the sun? My groups hypotheses is a 60* angle but so far from now a 90* angle is receiving more power, WHY?`
280: Can liquid nitrogen freeze fire?
281: Why the ring of Saturn is visible to us and the other outer planets like Uranus ring's is invisible to us?
282: Can a plant stay alive without light?
283: How can we measure the speed of light?
284: How long would it take to travel one light year at one tenth the speed of light? I have been getting ten years, though I heard light years are different than other ways of measuring distance. I just need a proffessional view on this.
285: Do plants with non green leaves have chlorophyll and photosynthesis?
286: What is the reason fireflies emit light and how does it work?
287: Hello, I'm doing a project over chemiluminescence and glow sticks and I have some questions about them, so I was wondering if anyone could answer them!
1. What are some alternative uses for chemiluminescence instead of just producing light?
2. In what cases can the chemicals in glow sticks be harmful?
3. What causes some glow sticks to be more bright or long lasting than others?
4. How does chemiluminescence occur in living organisms?
5. Why does chemiluminescence not produce much heat?
Thank you for your time!

288: What is the safest place to be if a supernova occurs?
289: Is Venus hotter than Mercury because it is full of carbon dioxide or because it does not have an atmosphere?
290: What is the difference between gamma particle and gamma rays? Are thee the same thing or not ? This confuses me.
291: Why a black hole is actually black? Why light when enters into it does not bright inside?
292: Why the universe has not end and why is it too big?
293: How the heat of sun come in earth when there is no medium?
294: What things reflect light?
295: I know that different colors have different wavelengths, with the color blue having a shorter wavelength than other colors. My question is: When light is reflected off the surface of the ocean, does this shorten or lengthen the wavelength of the colors in the light spectrum? Thank you so much for your time!
296: Leaves of plants like cabbage are purple in color, then how are they able to carry out photosynthesis?
297: Hello, I am in 7th grade and was in Science class while thinking, Man to Mars communication. My question would be, while Man is on Mars will they be able to communicate back to family and friends? I know they will be able to back to the Space Station but I was curious about the family and friends part. If so, will this be freely chosen times to talk or schedule time? Thanks,
298: Why does soil heats up faster than sand?
299: If you are trying to find the bottom of the sea the water is black, Why is that? How far is the bottom of the sea? Well bye and thanks for letting me use this program.
300: How fast do meteors travel? How far is Mars from Earth, and how fast can we get there?
301: How is oxygen released in the air?
302: How do flowers get their colors?
303: Why does neon glow?
304: Why does green light slow down more than orange light does when passing through an object?
305: Why aren't plants black? In theory, a black plant would absorb light from all wavelengths. However green plants (i.e. plants that reflect rather than absorb green) seem to have enjoyed an evolutionary advantage. According to Darwin they must have been the most fit, but what made them the most fit?
306: To prove that light is essential for photosynthesis we use black paper, how could we get correct results? When black paper absorbs more heat, does this fact hinder our result?
307: After being outside when it is sunny, why do you see green spots when you come inside?
308: How does light move?
309: What is the size of a star?? And why a star is looking so little & blinking?
310: Why does the sun have sunspots even doe the sun is the sun?
311: Why do chlorophyll makes plants look green if light is not green?
312: How does a magnifying glass work?
313: What is a measure of energy?
314: What is radiation?
315: Why is water clear in a bottle and on Google I asked what is the color of water and it said blue. My question is why is water clear in a cup?
316: Is the sky bluer when you look straight up at it or from far away?
317: If the statement "Heat Rises" is true...then, why is the north colder than the south?
318: Is WiFi matter?
319: Why do we get heat from lights?
320: How can we know that something is matter or not?
321: How long does it take the sun's light to reach Earth?
322: What is a volcanic lighting and how does it happen?
323: Why can light pass through glass?
324: Where and why do plants grow better, in the darkness or in the light?
325: How many wavelengths would you need to have in the photo receptors to make color vision like humans?
326: Please tell me specifically how the colors reflect, and absorb heat?
327: How do magnifiers make things look bigger or more clear?
328: Can plants live on a light bulb or do they need sunlight?
329: I have few questions to ask about for my project which is a solar cooker. Firstly, I would like to know any materials that are suitable to absorb heat. The solar cooker that I'm about to make has to only heat or boil the water so I would love to know any material that is suitable to absorb heat. Next, I made a thermal paste (toothpaste and Vaseline) but it didn't seem to work. I am sure that the quantity used is correct so I would love to know any alternative paste that I can use instead. If possible please give any relevant information regarding this project. To build this project I'm not allowed to use metal, mirror and glass. Thank you very much and hope you could answer me as fast as possible.
330: Between which lines on a ray diagram will you measure an angle of reflection?
331: I would like to know what causes the redness and a green flashing light in my mom's eyes.
332: If light is traveling at 186000 mph and is absolute. How can it reflect without being shattered into other elements or destroying the object it hit? Also how can it reflect and maintain its same speed and frequency?
333: Do objects in darker color reflect or absorb the most light?
334: Which color of filters block ultraviolet light?
335: What effects does sunlight have on colors (particularly black or dark)?
336: What are ways for our eyes to see better with?
337: What is a virtual particle and its relationship with quantum field theory?
338: Does the color of the light bulb affect the temperature around it?
339: Why the speed of light is the absolute speed limit in the universe?
340: How do pitcher plants collect the sun for food?
341: If you could somehow create a 'vacuum' around your home, would that stop the transfer of heat and cold in and out of the structure?
342: About one-two years ago I stared at the sun until I saw a full circle. When I looked back down at earth, it was dark for about a minute. I closed my eyes during this time. When I opened my eyes, everything was normal - no pain, no darkness. Was that even normal?
343: Why does light affect the rate of photosynthesis?
344: I wonder why we have thunders?
345: Why is the sea really clear in some places and not in others?
346: Why is some ice dark blue while others are light blue or white?
347: How does a television remote send a signal to the receiver, and how does the receiver pick up the signal?
348: How do pictures go from a camera to a piece of picture paper?
349: Does space ever end?
350: Can photosynthesis and respiration create a cycle of energy? Why?
351: Can and how does eye color effect the way you see colors? I've noticed that sometimes my friends will see a color differently that me, like I see dark orange and they see red.
352: Does the sun help plants grow? IF it does, then how?
353: Radiation from space hits Earth every day. The radiation particles are moving faster than light and colliding with Earth. How can you slow down these particles? And one last question can chemical energy from chlorophyll in plants be converted into electrical energy? Please answer my question it will be really helpful to get a good response.
354: Which color light affects plant growth the most, red, yellow, blue, or green?
355: Where does sunlight fade paper first, in books or in magazines?
356: Why is blue hotter than purple?
357: How do colors absorb light?
358: Why do sunlight give off oxygen?
359: Why do different colors of light have different energy levels?
360: Will the stars appear very bright in new moon day? Or full moon day?
361: Is the colored light the result of an electron moving to or from the ground state?
362: How should the rate of photosynthesis change if the amount of light reaching a leaf decrease?
363: If when you look, light goes from your eyes to an object back to you eyes. Then wouldn't it be possible to combine the electrons and neutrons so stuff would grow out from where you are looking. True you could\'t see it grow, that would be cool but it would be a faster way to make stuff made out of one material? What I'm trying to say is that you look at a spray or whatever, it would look white and when you look away or when it runs out or whatever there would be a wall of whatever element you made bigger depending on where you looked. I hope you try, research or just honor my request.
364: Why is it not possible to see around corners?
365: Do different colors of light change the color of a plants' petals or their growth?
366: How does bleaching powder works?
367: Who discovered that black light absorbs heat better than lighter lights?
368: What happens to an object that absorbs a lot of light?
369: Hello! I am doing a school project on trees. I saw your article on the question "How come plants produce oxygen even though they need oxygen for respiration?" I have a similar question. I am wondering if there is a way to make trees produce more oxygen. I know that they produce oxygen during their photosynthesis by using carbon dioxide, water, and sunlight but I wonder if there is any way to make them produce more by giving them large amounts of those things. Thank you for your consideration of my question.
370: What would happen to the rate of photosynthesis if the amount of water and carbon dioxide decreased?
371: Does the consistency of an object increase or decrease magnification, thus play a role in refraction?
372: Is there radiation in lightning?
373: How does the sun heat the earth?
374: I have been searching for an answer to this question for quite some time. Do different colors 'reflect' heat at different rates? I am not talking about light at all. In a dark room, will different colors reflect HEAT at different rates? I believe that I know the answer, but have not been able to find it anywhere.
375: I am doing a presentation, and I can't find anything on how color affects size. If I have a white object it will appear smaller than a black one, right? I tried but am not finding a reason!
University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2015 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use