Recent questions tagged scientific-reasons

Description : What causes milk to rise up when we boil it?

Last Answer : Milk contains 87 per cent water, 4 per cent proteins and 5 per cent lactose (milk sugar). When we boil milk, the fat, sugar, proteins and minerals get separated. Since they are lighter than ... vapour pressure raises the creamy layer. So the milk pushes the creamy layer out and milk spills out.

Description : How does a compact fluorescent lamp consume less electricity than conventional fluorescent lamps and bulbs?

Last Answer : Fluorescent lamps are based on the phenomenon of gas discharge between two electrodes at the ends of a glass tube. Generally these tubes contain a little mercury in the low-pressure vapour phase. When ... poor efficiency. The three types of lamps may have a typical efficiency ratio of 8:6:3.

Description : Why does an egg (with the shell) burst when cooked in a microwave oven?

Last Answer : Microwave radiation is generated in an electronic tube called a magnetron, and passes along what's called a wave-guide into the oven cavity. The microwaves are absorbed by foods - a characteristic that ... encourages even cooking and (if we forget to prick the yolk) helps to confine the explosion.

Description : Why is fuel used in airplanes different from those used in motor vehicles?

Last Answer : Aviation turbine fuels are used for powering jet and turbo-prop engine aircraft. Kerosene was used to fuel the first turbine engines. Kerosene-type fuel was chosen as having the best ... is only significant demand in very cold climates where its better cold weather performance is important.

Description : How does a rechargeable battery work? What is the life of such batteries and how are they different from ordinary batteries?

Last Answer : Electrochemical cells and batteries are identified generally as primary and secondary batteries. The primary batteries cannot be easily or effectively re-charged electrically and hence are discharged (used ... cycles (one cycle represents one discharge and charge) depending on its design parameters.

Description : What is the peculiar smell of the earth after the first shower?

Last Answer : ANSWER I: The characteristic earthy odour of soil is caused by the production of a series of streptomycete metabolites called geosmins. These substances are sesquiterpenoid compounds and unsaturated compound ... ) is the microbial product found in the spores is responsible for the pleasant smell.

Description : How is a ventriloquist able to throw his voice?

Last Answer : ANSWER I : Ventriloquism is the art of projecting or `throwing,' the voice so that is appears to come from a different source. The performer also directs the attention of the audience to the place from where ... of light that hits it, while the ear isn't so sensitive to the direction of a noise.

Description : Does frequent switching on/off of a fluorescent lamp reduce its life?

Last Answer : The life of a fluorescent lamp is essentially determined by life of the cathode filament it uses. A conventional fluorescent lamp employs closely wound coil of tungsten wire as filament. Upon switching on ... of continuous burning can be halved or made still less, just by frequent switching on/off.

Description : How do touch screens work?

Last Answer : Touch screen monitors - where you can use your finger on the computer screen to navigate through the contents - have become more and more commonplace over the past decade, particularly at public information ... allowing a touch with almost any object - except hard and small objects like a pen tip.

Description : How does the solar wind affect Earth?

Last Answer : Solar wind contains intense clouds of high energy particles which are produced by solar storms. These clouds of particles affect Earth. These clouds are called coronal mass ejections. They reach the earth ... by the solar wind, especially the storm clouds that the Sun launches our way very often.

Description : Why is the @ symbol used in an email address?

Last Answer : ANSWER I: The e-mail address generally has two parts, user id and the domain name. The @ (at) symbol is used to separate the user id from the domain name in the e-mail address. The e- ... reached on the Internet by giving the email address (also called the User's Uniform Resource Locator (URL)).

Description : What is Polaroid sunglasses made of?

Last Answer : ANSWER I: Polaroids are thin and large sheets of crystalline polarising material (made artificially) capable of producing plane polarised beams of large cross section. As early as 1852, it was ... to return to their original shape, resulting in the loss of their light absorbing properties.

Description : Why does rain come in drops and not in a continuous stream?

Last Answer : When warm wet air rises, it cools and water vapour condenses to form clouds. A cloud is made of small drops of water or ice crystals, depending on its height and how cold its surrounding air is. ... Giant droplets fall rapidly. Thus drops keep on falling side by side and not in a continuous stream.

Description : Why is the Earth's core hot? What caused it to heat up? Is it still heating, or now cooling?

Last Answer : Scientists estimate that temperature at the Earth's core is about 5538{+0}C. Much of the heat inside the Earth today comes from elements that were present when the planet was first formed billions of years ... function of their half-life. Therefore, Earth's core is not heating up, it's cooling down.

Description : How is carbon dioxide removed from blood before it is exhaled?

Last Answer : In humans, carbon dioxide is generated in the tissues during oxidation of glucose, in order to liberate energy, which is resumed to perform body functions. Before exhalation through lungs the gas is transported ... than the tissue capillaries. Nearly 23 per cent of CO{-2} is transported this way.

Description : How do certain species of birds such as Humming Birds, Terns, Gulls and Kestrels remain in the air without a forward motion?

Last Answer : ANSWER I: The humming bird's wings consist mainly of elongated hand bones to which the flight feathers are attached, and the whole wing can rotate as does the wrist. The short arm bones not ... only birds which can fly forwards, backwards, up, down, sideways or move instantaneously in any direction.

Description : How does ballast-less track provide safe travel?

Last Answer : ANSWER I: Ballast is a prime component of the track that acts as a vibrant medium to transmit from the rail surface the weight of the train down to the formation, the wells set on ... cost involved in laying a ballast-less track is more initially but it requires less recurring maintenance cost.

Description : What is Computer Simulation Technique?

Last Answer : ANSWER I: `Simulation' in general terms can be defined as the representation or imitation of a system in its realistic form. When a computer program is used to create a model to mimic a ... frame, combustion, and weather and ocean circulation are some of the examples that need huge computer power.

Description : Do animals also have blood groups like humans?

Last Answer : In man blood group is applied to single factor. This factor is agglutinogen and is also called antigen. It is found on the surface of red blood corpuscles. Accordingly a person with `A ... set off strong transfusion reactions. Such reaction can occur on the second or on subsequent blood transfusion.

Description : Why does sea water not erode coastal areas in all places?

Last Answer : The main cause of coastal erosion is the kinetic energy of wind. The main medium of transmission of wind energy is through wind generated water waves. Occasionally waves are also generated by other ... littoral drift (as in Chennai Marina), stopped by the harbour structures jutting into the sea.

Description : How does scratching cure itching sensation?

Last Answer : Very sensitive, rapidly adapting, mechanoreceptive free nerve endings that elicit only the tickle and itch sensation are found almost exclusively in the superficial layers of the skin. This sensation ... The anterolateral system is a cruder type of transmission system than the dorsal column system.

Description : In the past, why was injection administered in the stomach for dog bite?

Last Answer : ANSWER I: This is the only disease where the vaccine is given after the exposure (post- exposure). Nervous tissue vaccine (NTV), is one of the vaccines administered for dog bite. This vaccine is ... it does not require a subcutaneous layer. Hence, it can be given in the buttocks or arm region.

Description : What is the pH of rainwater? Is the pH suitable for drinking?

Last Answer : The technical definition of pH is that it is a measure of the activity of the hydrogen ion (H+). It is essentially a measure of acidity. The pH scale ranges from 0 -14. In the ... of rainwater tends to fall drastically, rainfall is highly acidic and the water thereby becomes unfit for consumption.

Description : What is the difference between TV screen and computer monitor?

Last Answer : ANSWER I: Computer monitors are capable of accepting signals only from the central processing unit of a computer. Therefore they are unable to reproduce a colour image from a composite video signal ... prevent flicker. This requires electronics that operate twice the speed as that of a television.

Description : Like ordinary paints do metallic paints also fade?

Last Answer : Metallic paints do fade. It depends on the quality and the type of the aluminium paste used. Usually in most of the metallic paints, the commonly used pigment is aluminium pigment in the form of ... a short period of coating, whereas cars coated with metallic paints shine even after a long time.

Description : How does a lightning arrestor work?

Last Answer : ANSWER I: Lightning, is a form of visible discharge of electricity between rain clouds or between a rain cloud and the earth. The electric discharge is seen in the form of a brilliant arc, ... a cone of protection, which has a ground radius approximately, equal to its height above the ground.

Description : Why do houseflies rub their front legs together?

Last Answer : Housefly (Musca Domestica) is a common insect found in all places. It has a very short life span. Adult houseflies feed on human and animal food and waste materials and often use buildings as ... whenever a housefly rubs its legs, lakhs of bacteria are discharged from the legs for each rubbing.

Description : Why do lips become dry during winter?

Last Answer : Our skin is endowed with both cold and warmth receptors. There are more cold receptors than warmth receptors. Therefore peripheral detection of temperature mainly concerns detecting cool and cold ... of infarction necrosis of affected areas even after the temperature begins to return towards normal.

Description : What is meant by ozonised mineral water?

Last Answer : Ozone is a blue gas with a relative molar mass of 48 and molecular formula of O {-3}. It converts back into oxygen after its oxidising process. This makes it the most eco-friendly treatment ... control rate of injection. The amount of ozone to diffuse in water depends on the contamination of water.

Description : How can we test the purity of honey?

Last Answer : Answer I: The purity of honey can be easily detected using different methods. One such test is the aniline chloride test. Here aniline chloride is first prepared and then used for testing. Three parts of ... spoon of honey in a cup of water and find out whether it dissolves to check its purity.

Description : How does the camel walk in the desert easily?

Last Answer : The camel is dubbed the `ship of the desert'. It can adapt itself easily to the hot conditions due to various reasons. Its special adaptation features are its hump, long legs, long hair and special eyelids ... can see through it. So a camel can find its way through a sandstorm with its eyes closed.

Description : How is sex determined in dioecious plants?

Last Answer : Dioecious: Having male and female reproductive organs in separate plants or animals. More than 90 per cent of flowering plants produce perfect flowers that have both male and female ... and developed individuals secrete the pheromone so as to masculinise the surrounding juvenile plants.

Description : Why is fire hot?

Last Answer : Chemical reactions can be either exothermic (heat liberation) or endothermic (heat absorption). Oxidation reactions are exothermic and reduction reactions are endothermic. Combustion is an oxidation reaction and hence is ... the major constituent in the air are also heated. That is why fire is hot.

Description : How do icebergs form?

Last Answer : Icebergs are blocks of fresh-water ice that break off from glaciers and float out to sea. Glaciers are formed in Polar Regions where snowfall lasts for centuries, or even millennia, without entirely melting, ... and falling tides cause slabs of ice to break off and form moving "rivers of ice".

Description : How does the solar wind affect Earth?

Last Answer : Solar wind contains intense clouds of high energy particles which are produced by solar storms. These clouds of particles affect Earth. These clouds are called coronal mass ejections. They reach the earth ... by the solar wind, especially the storm clouds that the Sun launches our way very often.

Description : Since clouds contain tiny water droplets, why are rainbows not permanently present?

Last Answer : On a rainy day, sunrays, which are polychromatic(with all the seven colours), fall on water droplets at a certain incident angle adn refract with certain other refractive angle because water ... they are numerous and closer against an appropriate viewing angle to allow the cooperative phenomenon.)

Description : What is Radio Therapy?

Last Answer : Radiotherapy, also called radiation therapy, is the treatment of cancer and other diseases with ionising radiation. There are generally two types - internal radiotherapy and external radiotherapy. Internal ... cancers. It is referred to as high linear energy transfer (high LET) radiation.

Description : Does the change in mother's food affect the baby?

Last Answer : Whatever the nursing mother eat will be secreted in her milk, but in insignificant quantities. Generally if the mother tolerates a particular food item well the baby also tolerates it well. A normal well nourished ... purgative etc., she has to stop feeding her baby as long as she is on those rugs.

Description : Is it safe to eat vegetables or fruit from the garden after a mosquito control application?

Last Answer : Fruits and vegetables exposed to malathion at mosquito control rates can be safely eaten after washing the food to cleanse it of germs and microorganisms. In fact, malathion is registered by the EPA for the control of many insect pests on a wide variety of fruit and vegetable crops.

Description : Is the Spray harmful to people or pets?

Last Answer : The amounts of mosquito control pesticides that are sprayed out of the trucks are not harmful to people or pets. However, as with any pesticides, it is a good idea to keep exposure to a ... should be experienced. People who are sensitive should call the office and notify us prior to any spraying.

Description : When can I expect to see a spray truck?

Last Answer : When conditions meet the required criteria, you should see a spray truck every 5 to 7 working days (weather permitting). Adulticide spraying can vary from year to year due to environmental conditions, which include rainfall amount and tide changes.

Description : Why can't mosquito control programs spray during the day?

Last Answer : Mosquitoes are more active in the evening, and people are less active. The second reason is the spray will be lifted quicker from the ground due to rising air currents during the day. Daytime spraying is also not practiced to avoid killing beneficial insects.

Description : Are mosquitoes attracted to some people more than others?

Last Answer : Yes. Mosquitoes are attracted to the carbon dioxide (CO2) emitted from the breath and pores of humans. In addition to CO2, some species of mosquitoes are attracted to certain fragrances and ... mosquitoes wear unscented products such as hair spray, soap, deodorant, etc. and light colored clothing.

Description : What purposes do mosquitoes serve?

Last Answer : Mosquitoes are an important link in the food chain. Many animals depend on them as a source of food. During their aquatic stage, mosquito larvae provide food for the other aquatic ... of this need for nourishment, mosquitoes are important pollinators of wildflowers during this feeding process.

Description : How many kinds of mosquitoes are there?

Last Answer : Throughout the world there are over 3,000 species of mosquitoes. Florida has 76 mosquito species from 13 different genera, 30 of which occur throughout the entire state. There are 14 species in Bay ... -breeding mosquito, and on our visits to residents' homes this is the most common mosquito found.

Description : Is the mosquito a carrier of AIDS causing virus?

Last Answer : Acquired Immune Deficiency Syndrome (AIDS) is caused by Human Immunodeficiency Virus (HIV). The presence of HIV in blood, semen and vaginal secretion of infected people promotes the spread of ... . Further, studies on epidemiology of AIDS have provided no evidence linking mosquitoes with disease.

Description : Soaps come in different colours. But why is soap's lather always white in colour?

Last Answer : Lather or foam is nothing but a large collection of small soap bubbles. A soap bubble is , in turn, a very thin film of soap solution enclosing some air. Because of the low surface tension of ... collection of bubbles gets scattered. That is the reason why all kinds of lather or foam appear white.

Description : How does lightning affect TVs?

Last Answer : Lightning is actually a sudden discharge of high voltage and high current arising out of large voltage (potential) differences between charged clouds. These surges, in their path towards the earth, can ... that they can destroy the equipment even if they are off but connected to the mains/antenna.

Description : Both Infrared and Microwave bands are invisible to the human eye. Then how are IR and microwave images from remote sensing satellites printed? How do they substitute the wavelengths?

Last Answer : Both infrared and microwaves are part of the electromagnetic spectrum, which stretches from radio waves to gamma rays. each band of this spectrum corresponds to a small range of frequencies. Each ... levels) are finally printed on a computer screen as a picture or as a conventional photograph.

Description : What is the difference between a sodium vapour lamp, Which gives out a yellowish colour illumination, and a mercury vapour lamp that gives out a white colour illumination?

Last Answer : Answer I: The light in Sodium Vapour lamp is from an atomic emission process whereas in Mercury Vapour Lamp it is, finally, from fluorescence emission. The mechanism of light emission in a sodium ... from a fluorescent lamp is moderate (60 lumens/watt) while the color-rendering index is high.