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Question: Why does the sky looks blue?
Answer: The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.
Posted By: shashank,Scienceutsav

Question: Can u please tell me are thier something called ALIENS in space?
Answer: Science says don't believe until it has proven experimentally or seen by yourself. To be frank I am not a believer of those UFOs(Unidentified flying object) and Aliens. I feel they are the fictitious characters created by crazy world. They refer to the living beings beyond our earth which are anti Human being, further there is also a presumption that they are very dangerous with humongous power. For Believers: http://science.howstuffworks.com/space/aliens-ufos/ufo.htm
Posted By: Namitha Shekar,Widia Poornaprajna School

Question: If fire needs oxygen to glow, then how does sun have fire?
Answer: Sun is made up of helium gas and hydrogen gas. when hydrogen atoms collide with high speed tremendous amount of energy is liberated and its called atomic/Nuclear energy. there are two types 1. Nuclear fusion (What happens in sun) 2. Nuclear fission (Splitting of big atom into smaller one) Nuclear fission is used in nuclear power centers to produce electricity. In karnataka we have nuclear power station in Kaiga, Uttara kannada dt. It is also used to make nuclear weapons which are very dangerous.
Posted By: Atharva Rahul Pradhan,B.G.S National Public School

Question: A COAL CATCHES FIRE WHEN BLOWN,BUT A CANDLE GETS OFF WHEN BLOWN.WHY?
Answer: Burning process is called as combustion where materials will react with oxygen at particular temperatures called ignition temperature. Each material will have definite ignition temperature. Lower the ignition temperature things will burn in less heat eg Petrol Carbon di oxide is having higher density than oxygen so it pushes oxygen away So it is used as a fire extinguisher. Now to stop the fire we have to isolate either any of the 3 things material or oxygen or Heat. Burning Coal will have heat in it when we blow it has both oxygen and CO2. So it will use oxygen to burn. But in case of candle when blown it loses its ignition temperature. Whereas in magic candles we can see them burning even after blowing because the ignition temperature of the thread used in the magic candles is less.
Posted By: VIJETH.P.A,widia poorna prajna

Question: what is the reason for disappearence of daimond when it is exposed to intense heat? I have lost a daimond in the same way!!!
Answer: Diamond is one of the allotrope of carbon just like charcoal or graphite what you call it as lead in the pencil but the only difference is the arrangement of carbon atom. so when diamond is heated it will get burnt and converts into ashes. Keep posting !!
Posted By: VIJETH.P.A,widia poorna prajna

Question: Why does radium glow in d dark?? ive been fed up so please answer my query
Answer: Its not just radium, many other things we see glowing naturally in the dark like Fireflies, jellyfish and glow sticks etc !! Its because of following of things 1.chemiluminescence 2.Phosphorescence 3.Fluorescence 4.Bioluminescence Chemiluminescence is the production of light from a chemical reaction. Two chemicals react to form an excited (high-energy) intermediate, which breaks down releasing some of its energy as photons of light. A + B -> AB* -> Products + Light 2.Phosphorescence and Fluorescence(Photoluminescence) A fluorescent paint glows under a UV lamp, but stops glowing as soon as the lamp is turned off. A phosphorescent paint keeps glowing for a while as Phosphorescent substances have the ability to store up light and release it gradually. In Bulb, gases absorb high-energy electrons, and then fluoresce, or re-radiate that absorbed energy at a different frequency which we see it as a different light. (I dont know if kids will understand this) If the molecules of the substance can get from the ground state to a metastable state, and if the metastable state can slowly decay back to the ground state via photon emission, then we have phosphorescence. (Is not science awesome ?? We will see this with an experiment in the lab, please enquire for the free demo class on this )
Posted By: ScienceUtsav Scientist,Kendriya Vidyalaya Malleswaram

Question: How can some animals see in the dark?
Answer: Nocturnal animals are capable of collecting enough light to see clearly in the dark. They have bigger eyes and wider pupils. Eyes have two types of cells viz Rod cells which are more light-sensitive and Cone cells. Their retinas are loaded with more rod cells, than the cone cells. Some snakes and animals use infrared sensory organs to detect and hunt warm-blooded prey. These infrared "eyes" are cuplike structures that form crude images as infrared radiation hits a heat sensitive retina.
Posted By: harsha,NA

Question: What is there in outerspace
Answer: Outer space, or simply space, is the void that exists between celestial bodies, including the Earth.It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos. Observations and theory suggest that it also contains dark matter and dark energy. courtesy: http://en.wikipedia.org/wiki/Outer_space
Posted By: Anmol,NA

Question: why blood is red in colour
Answer: Blood looks Red, physics says Red blood cells absorbs all the light and throws only red which makes it look red. The reason it's red is because it's got iron in it. If you look at them from the side, they look like a number eight and that's because they've got a thick ring round the edge and a flattened center, a bit like a doughnut. They're crammed with a substance called hemoglobin, and hemoglobin is that stuff that carries oxygen around the body. It's a protein - in fact it's four proteins stuck together. In the center of those four proteins there is an iron ion. Because it's got iron in there it's the color red. Now lots of animals have a different version of that protein. For instance, the horseshoe crab has blue blood because they use copper instead of iron. The real hippies of the hemoglobin world are a kind of annelid worm that lives in the sea. It actually has blood that's purple when it's oxygenated. Please watch following video http://www.youtube.com/watch?v=CRh_dAzXuoU
Posted By: K.N.Bharathwaj,Jnanodoya school

Question: Why Himalayas are cold and moist ??
Answer: Generally the climate on mountains get progressively colder with increased altitude (the higher up you go). This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat. The cooler the temperature the less evaporation there is, meaning that there is more moisture in the air
Posted By: shashank,Scienceutsav