jueves, 9 de febrero de 2017

The Great Pacific Garbage Patch




The Great Pacific Garbage Patch
 
As Big as Texas!
Right now, there is a gigantic “soup” of trash floating somewhere between California, Hawaii and Asia. This is called the North Pacific Gyre, or more commonly referred to as the Great Pacific Garbage Patch. It is a swirling collection of plastic debris, or garbage, in the middle of the Pacific Ocean that is bigger than the state of Texas! This enormous collection of trash moves with the currents of the ocean and cannot be seen from the sky because most pieces are very tiny and float a few inches below the water’s surface.


How Did it Get There?
No one really knows when the Great Pacific Garbage Patch began. In the 1970s, scientists started studying the area. They noticed that garbage was floating in the water, collecting together in a cluster, or group. They could see that ocean currents carried this plastic garbage. Currents are the flow, or continuous movement, that water takes in one direction. Some large currents are circular; instead of moving in a straight line, they move in a circle, kind of like the way water moves when you flush a toilet! These circular currents are called gyres (rhymes with fire,) and the Great Pacific Garbage Patch is basically one enormous collection of trash floating in a huge circular current. The only time trash leaves the gyre is when it sinks, or is flushed out by a big storm and washes ashore hundreds of miles away.
 
 Where Does the Trash Come From?
About 80% of the trash in the Great Pacific Garbage Patch comes from activities on land. Litter like plastic bottles, bottle caps, and candy wrappers can end up in storm drains or in rivers and streams that empty into a bay or the ocean. Also, in coastal cities like San Francisco and Los Angeles, the wind often blows litter into waterways or directly into the ocean. The rest of the trash in the Garbage Patch (20%) comes from activities at sea. Every year, about 100 million containers are shipped over the world’s oceans. One of the shipping routes is between Asia and North America. There are frequent, severe storms along this route, which cause hundreds of containers to go overboard each year. Many of these containers hold things like tens of thousands of shoes or millions of plastic shopping bags and other plastic items.
 Persistent Plastic
Plastic tends to make up a large part of ocean debris. Since plastic is buoyant, or able to float, it can easily travel long distances on ocean currents. In addition to being buoyant, plastic is also persistent. That means it lasts a vevery, very long time without naturally breaking down or decomposing into smal particles or tiny pieces. Another way of saying this is that plastics do not biodegradBio means “life,” and degrade means “tobreak down.” When something is biodegradable, it means it is made from something natural that was once alive (eithea plant or an animal.) It also means it can decompose and return to the natural elements or naturally occurring materials found onEarth. Most plastic is made from petroleuor oil, which is not biodegradable. Thereforit can take 500 years for a piece of plastic twear down into smaller particles! And even it still doesn’t return to a natural element. It just becomes a very tiny piece oplastic. Another source of plastics in the ocean, are nurdles. These are small plastic pellets, or balls, that get melted down to make a variety of plastic products. Nurdles cause big problems! They often end up in the ocean where animals will eat them and get sick from the poisonous chemicals that nurdles contain. Nurdles also damage the bodies of fish, which makes it hard for themto breathe through their gills.
The Problem with the Patch   
Some people think that because the ocean is so big, a gyre full of floating garbage doesn’t matter that much. Well, they’re wrong! Oceans are complicated ecosystems where billions of organisms, or living things, live in natural balance. Plants like algae, plankton, and seaweed make up the beginning of the food chain for animals such as shrimp, fish, jellyfish, birds, sea turtles, otters, dolphins, sharks, and whales. A food chain is the natural order of how animals get food. When plastics end up in our ocean, they often appear as food to animals and become a dangerous part of the food chain. Imagine a plastic bag floating in the ocean. It can look just like a jellyfish, which sea turtles and dolphins love to eat! When these animals eat plastic bags, it can choke them. It can also fill their stomach with trash that doesn’t digest or move through their bodies to provide them with the nutrition needed to survive. Often, animals will stop eating if their belly is full of plastic, and they end up starving to death! Each year, more than 1 million sea birds and 100 thousand marine mammals die from plastics. Not only do they die from eating, or ingesting it, they also die from getting entangled or caught in it. Plastic six-pack rings and plastic ropes and nets are common traps for fish, birds and other marine life that get entangled in them.
 
What can we do to help?
1. Stop buying water in plastic bottles. Instead, drink tap water from reusable bottles made from glass or steel.
2. Use cloth bags at the store instead of plastic bags. We often don’t even need a bag!
3. Put lunch items in reusable containers instead of plastic baggies. Carry a
reusable, metal spork so that you don’t need to use plastic utensils.
5. Eat ice cream in cones, not plastic cups.
6. Cut plastic six-pack rings so that animals can’t get caught in them.
7. Stop litter! Tell family and friends that litter hurts animals. Join beach clean-ups.
8. Pick up trash outside your home and sweep sidewalks with a broom. Hosing sidewalks wastes water and can push trash into storm drains.
9. Recycle! Learn your city’s recycling rules for plastic and other items.
10. Use bio-plastics made from plants like corn or potato. They biodegrade naturally.
 

 

 

 



domingo, 29 de enero de 2017

PLASTIC: POLYPROPYLENE (PP)

                               

Name: Polypropylene.    Resultado de imagen de polypropylene

Polypropylene (PP) is a thermoplastic polymer which is sometimes referred to as polypropene. Its resistance to acids, bases, and a plethora of chemical solvents makes it an ideal candidate for use in a large range of applications. It is also extremely durable. The most common Polypropylene manufacturing methods include extrusion and injection molding. These techniques can convert PP into a wide range of useful products used for commercial and industrial purposes.
One of the most versatile aspects of manufacturing with PP is the ability to mix additives in during the manufacturing process which give the material specific and special properties. For example, certain types of additives can be introduced that give Polypropylene dust and dirt resistant properties or make paint and ink easier to adhere to the material.

 
 
Polypropylene is occasionally recycled. PP is strong and can usually withstand higher temperatures. It's used to make lunch boxes, margarine containers, yogurt pots, syrup bottles, prescription bottles. Plastic bottle caps are often made from PP.
 
Polypropylene is:
A excellent chemical resistance, a high melting point, hard, but flexible, waxy surface, translucent and strong.

Uses:
Most bottles tops, ketchup and syrup bottles, yogurt and some margarine containers, potato crips bags, biscuit wrappers, crates, plants pots, drinking straws, hinged lunch boxes, refrigerated containers, fabric/ carpet fibres heavy duty bags/tarpaulins.
 
 

 

jueves, 26 de enero de 2017

METAL: GOLD

 
 

Name: gold
Symbol: Au
Atomic number: 79
Relative atomic mass (Ar): 196.966569 (4)
Standard state: solid at 298 K
Colour: gold
Classification: Metallic
Group in periodic table: 11
Group name: Coinage metal
Period in periodic table: 6
Block in periodic table: d-block
Electron shell structure: 2.8.18.32.18.1
CAS Registry ID: 7440-57-5

What are the Physical Properties of Gold?
Color
Bright Yellow.
Luster
It has a shine or glow.
Ductility
It can be beaten into extremely thin sheets of gold leaf.
Malleability
Capable of being shaped or bent.
Conductivity
Good electrical conductor.
Solubility
Solubility (ability to be dissolved).
Hardness
A relatively soft metal, gold is usually hardened by alloying with copper, silver, or other metals.
Density
It is a dense metal.
Melting point
It melts at 1065°C.
 
What are the Chemical Properties of Gold?
Chemical Formula
Au.
Activity
Gold is chemically inactive, it's extremely resistant to chemical action.
Compounds
Ready reducibility from compounds to metal.
Auric chloride and chloro-auric acid are its most common compounds.
Reactivity with acids
Aqua regia, a mixture of nitric and hydrochloric acids, has the ability to dissolve gold.
Isotopes
It has one stable isotope, 197Au.
Reactivity with Non-metals
Gold does not react with the Non-metals, except for halogens, with which it forms halides.
Alloys
Silver and platinum.
Gold is one of the few elements you can find just lying on the ground. This one-ounce nugget of pure gold was found in Alaska in 1890 by Hogamorth Marion, while on a trip to sell shoes to Eskimos. Seriously.
Gold is metallic, with a yellow colour when in a mass, but when finely divided it may be black, ruby, or purple. It is the most malleable and ductile metal; 1 ounce (28 g) of gold can be beaten out to 300 square feet. It is a soft metal and is usually alloyed to give it more strength. It is a good conductor of heat and electricity, and is unaffected by air and most reagents.
Gold is usually alloyed in jewellery to give it more strength, and the term carat describes the amount of gold present (24 carats is pure gold). It is estimated that all the gold in the world, so far refined, could be placed in a single cube 60 ft. on a side.
The most common gold compounds are auric chloride (AuCl3) and chlorauric acid (HAuCl4). A mixture of one part nitric acid with three of hydrochloric acid is called aqua regia (because it dissolved gold, the King of Metals). It is unaffected by air and most reagents.
 
Nuggets of native gold
 
DISCOVERY OF GOLD
Gold was discovered by known since ancient times in unknown at not known. Origin of name: from the Anglo-Saxon word "gold" (the origin of the symbol Au is the Latin word "aurum" meaning "gold").
Gold has always fascinated people and gold is certainly one of the very first metals known. Nobody knows who picked up a gold nugget first but it would have been because it was shiny. Gold was highly valued from the earliest recorded times in history. It seems that the Egyptians developed gold smelting some 5600 years ago (about 3600 BC) using clay blowpipes to heat the smelter contents. Egyption inscriptions dating back to 2600 BC describe gold. Gold workers from Mesopotamia (known now as Iraq) made one of the earliest known pieces of gold jewellery in about 2600 BC. Gold is mentioned several times in the Old Testament. Tutankhamun's funeral mask is one of the most iconic gold pieces known. It was made around 1223 BC and is a stunning piece of ancient gold craftsmanship.
Ancient Egyptians had been working with gold for at least 1700 years before this mask was made.
 
The famous mask of Tutankhamun, made over 3300 years ago in 1323 BC.
.
 
APPLICATIONS
Gold is used as buillon and in jewellery, glass and electronics. Jewellery consumes around 75% of all gold produced. Gold for jewellery can be given a range of hues depending on the metal with which is alloyed (white, red, blue, green etc.). Colloidal gold is added to glass to colour it red or purple, and metallic gold is applied as a thin film on the windows of large building to reflect the heat of the Sun's ray. Gold electroplating is used to in the electronic industry to protect their copper components and improve their solderability.
Gold is used to cure rheumatoid arthritis, under a treatment called Chrysoteraphy. It is prescribed when treatment with non-steroid antu-infiammatory drugs is failing to give relief.
Dentists have used gold for filling cavities (before mercury amalgam became available), for crowns, and for other purposes since ancient times. Gold is malleable, nearly immune to corrosion, and hard enough to form a biting surface that can be used for years.
In certain regions of the world, especially in Eastern Europe, the former Soviet countries, Central Asia, and the Caucasus, gold teeth are worn as a status symbol, a symbol of wealth.
   
       

Interesting Facts about Gold
  • A single ounce of gold can be pounded into a sheet 300 feet wide by 300 feet long. That's bigger than a football field! That same ounce can form a wire nearly 100 kilometers long.
  • South Africa used to be the largest supplier of the world's gold, but today China and Australia produce the most gold.
  • Gold flakes were sometimes sprinkled on the food of the wealthy during the Middle Ages.
  • Many people traveled to California during the Gold Rush in the late 1840s when gold was discovered at Sutter's Mill.
  • Gold can be pounded thin enough to allow light to shine through.
  • If all the gold ever discovered by man was melted down it would form a cube with sides of about 25 meters each.
 
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