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Atoms by itself are not good or bad. The human body has evolved over hundreds of millions of years to be able to survive in a certain environment. So, a system has evolved that can make the best out the environment it lives in. Certain compounds or elements that we can make or extract from the environment can be quite alien to our biology, they can interfere ...


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Mammalian sense of smell is in general exquisitely keen: even though we think of ourselves as an animal having a dull smell sense comapared to that of, say, a dog, a pig or a rat, receptors for certain scents are still triggered by molecules counted in the tens. So the outgassing of volatile wood oils from, say, a table, can still be miniscule and well ...


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The Earth is negatively charged. As a result anything electrically connected to Earth sharges this negative charge. That includes plants, but also you and I should we be walking barefoot.


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Plants are not perfect conductors. Indeed mature plant material (wood) is a pretty good insulator. Therefore I see no reason to assume that (small) charges would immediately dissipate. There are several reasons that charge could accumulate on the plant. Ionic transport within the plant is one. Ionic removal by wind is another. I don't know if either ...


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Camera sensitivity is a common topic. In short they mimic the sensitivity of the human eye. Also your statement that we can see violet in pictures of violet objects is not accurate. It refers to violet as a color, not the 'violet wavelengths' of the spectrum. When we see violet objects we do not see 'violet wavelength' light as much as other wavelengths ...


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To the point of Is it hard to measure the resonant frequencies directly: it's tricky and careful discussion of the measuring procedures is needed. Some of the main problems: Destruction of the open-end behavior: If you place the speaker and microphone in front of the vocal tract to measure the response, you may have just switched open end behavior of your ...


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Everyone is likely to have a similar pain threshold to electric shocks. If your friend wears leather soled shoes he will conduct static electricity to earth because they offer much less resistance to earth than rubber or plastic soled shoes. Wearing synthetic clothes may cause a similar effect. If he/she has lower resistance than you (by having sweaty ...


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The resonances are quite broad: each cavity will amplify a broad range of frequencies, spanning most of or more than an octave. Driving those resonances isn't as simple as choosing a pitch. You have to do some work to efficiently couple the different cavities to your vocal apparatus, and to maintain the resonance while you're singing. The people who are ...


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Many simplifying assumptions of our reality must be made to arrive at the results you're looking for (and that the other answers gave). I'll try to give my own 2 cents. I hope that anything incorrect in here will be corrected by other users - I'm mostly just trying to address some problems and confusion with these assumptions. When you jump, you lower your ...


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You are looking at this incorrectly. Pale skin allows the UV to penetrate more deeply than dark skin (that has the melanin in the dead skin cells). Since dark skin individuals absorb the UV in the dead skin layer, it make no difference if it causes DNA damage.


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Dark skin absorbs UV better than lighter skin. More specifically, melanin absorbs most of the UV radiation so that your skin cells don't have to.


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The elucidation of the structure of DNA began as an exercise in x-ray crystallography. If you shine a beam of x-rays through a crystal, it will act like a diffraction grating, and the points of constructive interference will show up as dark spots on photographic film. This had been used for decades to determine the structure of relatively simple molecules. A ...


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Any thoughts on the second question? Could laser damage the dna, or perhaps bones, which could result in some cell damage-cancer? How deep laser go? What I need to know about it?


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I will explain the basic idea. The ink that is in the skin is just metallic particles that on average have bigger size than the one the white cells can "fight" and remove from the system. Although the body recognizes the "alien" particles living in the skin and constantly fights them (and this is the reason the tattoo wears out) it is unable to remove big ...



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