Why are airplanes made out of Aluminum?

Why are airplanes made out of Aluminum?

Strong strength to weight ratio.  While the same can be said of exotic metals like titanium, aluminum is much cheaper. If not for the discovery of aluminum we would not the air travel system that we have today. Early airliners were made of wood until a famous crash where a beloved sports figure and everyone on board were killed. Wood rot was found to be the cause. It drew attention to the problem of using wood for building airplanes. Overnight almost, wooden airplanes were phases out and metal clad airliners like the Ford Tri-motor came into use.  .  Steel or iron is too heavy and other than exotic metals like titanium or non-metal structures like modern day composites were not known at the time. Aluminum is the metal of choice because of it's strength and lightness. Aluminum is not easy to refine from ore but it is the most plentiful metal on Earth. 

Why do airplanes have circular windows?

Why do airplanes have circular windows?

The sharp corners on square windows are places where stresses concentrate and multiply their effects, hence the term "stress risers." Cracks, buckles, and tears in the airplane skin tend to start at these points. The rounded corners in airplane windows are much less prone to this problem. Circular shapes are much stronger and resist deforming much better- ie like an egg! Also corners on external features such as windows would create much more drag on the air, meaning less fuel efficiency

Why do crocodiles sit with their mouths open ?

Why do crocodiles sit with their mouths open ?

Crocodiles, like all reptiles, have a skin covered in scales. This skin is designed to hold IN moisture, and to lessen heat loss. They are ectothermic (cold blooded) and therefore derive their body temperature from the surrounding air. As a result, they bring their temperature up by basking in the sun or absorbing it from warmed surfaces like rocks. They do not have sweat glands.  If a Crocodile gets too warm, it can only reduce it's temperature in three ways: get in the shade; get in the water; or sit quietly with its mouth wide open. The body heat therefore is lost through the soft, moist skin of the mouth and tongue. They bask in the sun to heat up, and if they ever overheat they sit with their mouths open to cool down.

Can it really rain frogs and fishes?

Can it really rain frogs and fishes?
Yes! It doesn't happen very often, but there are several known instances where frogs, fishes and others have been sucked up by tornadoes or violent winds associated with thunderstorms, and dropped down out of the sky miles from their ponds. Tornadoes may lift up animals into the air and deposit them miles away. Sometimes the animals survive the fall, suggesting the animals are dropped shortly after extraction. Several witnesses of raining frogs describe the animals as startled, though healthy, and exhibiting relatively normal behavior shortly after the event. In some incidents, however, the animals are frozen to death or even completely encased in ice. There are examples where the product of the rain is not intact animals, but shredded body parts. Some cases occur just after storms having strong winds, especially during tornadoes. Rain of flightless animals and objects has been reported throughout history. Raining animals is a rare meteorological phenomenon in which flightless animals "rain" from the sky. The phenomenon has never been witnessed or scientifically tested.

Why do frogs jump?

Why do frogs jump?
There are lots of animals (like alligators, snakes, owls, and even people) who think that frogs make tasty snacks. Since frogs don't have sharp teeth or claws to defend themselves against predators, the best thing they can do to avoid being eaten is to escape as quickly as possible when they spot a hungry-looking animal approaching them. Sproinnggg!!! Some kinds of frogs can jump distances up to 20 times their own body length in a single leap. When disturbed, frogs often jump into a puddle or pond where they can hide underwater. Their erratic zig-zag jumping on land also serves to confuse potential predators. In most frog species only the males croak. They croak to attract female frogs for breeding, and to warn away other male frogs from their territory. Female frogs think croaking is very sexy. Many kinds of frogs puff themselves up enormously with air when they croak. This amplifies the sounds made by the frog's vocal chords, kind of like how the stretched membrane of a drum works. This is why a little critter like a frog can make such loud noises! They hibernate in burrows or bury themselves in mud. Frogs and toads are cold-blooded and their body processes slow down as the outside temperature drops. (This is why you sometimes find sluggish-acting toads on cool mornings in the spring.) Frogs' bodies have some natural antifreeze built into them, but some kinds of frogs who live in especially cold climates can even survive being frozen solid.

How he makes her girl crazy

How he makes her girl crazy

Every girl loves a little romance. Giving your lady the romantic attention she so craves could do much to endear you to her. Being romantic doesn't have to be complicated or expensive. In fact, some of the most romantic things cost the least amount of money and are really quite simple. Surprise her. Catching your girl off guard is a great way to amp up the romance. Instead of always telling her exactly what to expect on your dates, leave some things up in the air, not allowing her to know specifically what she can expect until the much-anticipated date arrives. Praise her in front of someone else. Give her little love tokens. When a girl gets dressed up it is usually for her guy so tell her she looks great. Give your girl gifts, but make them meaningful. Instead of buying her expensive items that are nice yet not specifically romantic, focus on little presents that are budget-friendly and full of romance. Single roses, hand-written love poems and carefully written cards can all show your girl just how much you love her, and make it clear that you are romantic. Put thought into your dates. Dinner and a movie is great, but doing this every time you head out on a date is sure to get tiresome. Instead of making your dates as predictable – and generic – as can be, take time to plan something special for your girl, showing her that you think she is worthy of going the extra mile. Give her your undivided attention. “If a boyfriend doesn’t give her what she need, she walk away. You obviously can't always be in a private place with your girl, but even when you aren't you can make her feel like you are by giving her your full attention. Avoid looking around at others or getting distracted when out with your girl, showing her that you love her and that she has your full focus. In a healthy relationship, the feelings are mutual. You respect each other and have fun together. If this doesn’t describe your situation, there’s nothing wrong with you, but you probably do need to keep looking. Voice your feelings. Compliment her on her kissing like wow u have nice lips. If you love your girl, tell her. Don't assume that she knows. The more vocal you are about your feelings, the more clearly your girl will understand that you love her. Girls love having sweet nothings whispered in their ears, so don't hold back. Be affectionate. Hugs, pecks on the cheeks and even passionate kisses can do much to show your girl how much you care. Don't hold back on this affection as this physical contact is not only romantic, it also makes it clear to your girl that you are truly in love with her.  Decide ahead of time what your values are and how far you want to go. Pressure is not love, and it’s not even normal. That way, you won’t have to figure it out in the heat of the moment.

Marine shrimp farming

Marine shrimp farming is an aquaculture business for the cultivation of marine shrimp or prawns for human consumption. Commercial shrimp farming began in the 1970s, and production grew steeply, particularly to match the market demands of the United States, Japan and Western Europe. The total global production of farmed shrimp reached more than 1.6 million tonnes in 2003, representing a value of nearly 9 billion U.S. dollars. About 75% of farmed shrimp is produced in Asia, in particular in China and Thailand. The other 25% is produced mainly in Latin America, where Brazil, Ecuador, and Mexico are the largest producers. The largest exporting nation is Thailand.  Shrimp farming has changed from traditional, small-scale businesses in Southeast Asia into a global industry. Technological advances have led to growing shrimp at ever higher densities, and broodstock is shipped worldwide. Virtually all farmed shrimp are of the family Penaeidae, and just two species – Penaeus vannamei (Pacific white shrimp) and Penaeus monodon (giant tiger prawn) – account for roughly 80% of all farmed shrimp. These industrial monocultures are very susceptible to diseases, which have caused several regional wipe-outs of farm shrimp populations. Increasing ecological problems, repeated disease outbreaks, and pressure and criticism from both NGOs and consumer countries led to changes in the industry in the late 1990s and generally stronger regulation by governments. In 1999, a program aimed at developing and promoting more sustainable farming practices was initiated, including governmental bodies, industry representatives, and environmental organizations.

Crazy Bluebirds

The bluebirds are a group of medium-sized, mostly insectivorous or omnivorous birds in the genus Sialia of the thrush family. Bluebirds are one of the few thrush genera in the Americas. They have blue, or blue and rose beige, plumage. Bluebirds may sometimes remain in some northern areas in winter, much to people's surprise. Here's some tips for bluebird enthusiasts, on how to help bluebirds survive in winter.  Bluebirds can roost together in bird houses to keep warm. Insulate your bird houses by closing off all cracks, drainage holes, etc., with some sort of insulating material so less drafts and cold get into the bird house. Just leave the entrance hole open. Face bird houses away from prevailing winter winds. Bluebirds mainly eat fruit and berries in winter. Plant your property with an abundance of crabapples and native, berry-producing shrubs such as viburnums and hollies (like winterberry holly). Place these berry plantings in sunny, protected areas, blocked from winter winds. The bluebirds will have a warm place to eat and use less precious energy. Some bluebirds will come to food such as, hulled sunflower, suet, dried mealworms, and some of the many "bluebird meal mixtures" or nuggets. Generally most bluebirds do not learn to do this. You can certainly try putting out these foods, but your best bet is to have lots of berries planted in your yard. Bluebirds like water (may help with processing the berries) and will visit bird baths and heated bird baths. In general, when it is very severely cold, some people think it is a risk for birds to bathe. Holding off on the water, or placing sticks over the bird bath to only allow birds to drink, not bathe, may be a good idea in this situation. Many birds will eat snow in winter to get water.  Most bluebirds move out of the northernmost areas of their range in winter. Even ones that may linger eventually move on, once their berry sources are depleted or ice-covered. For bluebirds, and many birds, there is a trade-off of staying more north in order to be first to claim prime breeding territories, yet risking survival due to bad weather. Some of these tips may help them survive and you feel you're helping them. Bluebirds are truly beloved.