Hello, everyone! You might want to know more about Christmas. Thank you for visiting my blog! Christmas is my favorite holiday. In Argentina, the weather is almost always warm at Christmas. Preparations for Christmas begin very early in December and … Continue reading
Hey there! I’m researching rocks because I’m curious about them. I also like rocks because they are so interesting. Enjoy!
Geologists define rocks as aggregate of minerals. Minerals are naturally occurring, not unhealthy substances with specific chemical compositions and structures. A rock can be filled of many crystals of one or more minerals, or combinations of many minerals. Several exceptions, such as coal and obsidian, are not composed of minerals but are thought to be rocks.
People often use rocks for include building materials, roofs, sculpture, jewelry, tombstones, chalk, coal for heat, and more. Oil and natural gas can also be found in rocks. Many metals like a fork are made from rocks known as ores. Even, prehistoric humans used rocks as early as 2,000,000 B.C. Flint and other hard rocks were very important raw materials for crafting arrowheads and other special natural made rocks.
Around 500,000 B.C., rock caves and structures made from stones had become important forms of shelter for early man. During that time, early men had learned to use fire, a development that allowed humans to cook food as needed to survive and greatly expand their geographical range. Eventually, most likely no sooner than 5000 B.C., humans had realized that minerals such as gold and copper could be from rocks. Tons of ancient monuments were crafted from stone, including the pyramids of Egypt, built from limestone about 2500 B.C., and the buildings of Chichen Itza in Mexico, also of limestone, built near A.D. 450.
Since the 1500s, scientists have studied minerals and mining, fundamental aspects of the study of rocks. Georg Bauer published Concerning Metallic Things in 1556. By 1785, the British geologist James Hutton published Theory of the Earth, in which he explained his observations of rocks in Great Britain and his conclusion that Earth is much older than previous scientists before him had guessed. Geologists are scientists who study the earth and rocks, distinguish three main groups of rocks: igneous rocks, sedimentary rocks, and metamorphic rocks.
These distinctions are made on the basis of the types of minerals in the rock, the shapes of individual mineral grains, and the overall texture of the rock, all of which indicate the environment, pressure, and temperature in which the rock was made. Igneous rocks form when magma is below the land of the Earth or lava at the land of the Earth hardens. The minerals in the rock will make crystals or grow together so that the separate crystals make 1 crystal altogether. Igneous rocks and magma make up much of the oceanic and continental crust, as well as most of the rock deeper in the Earth.
Igneous rocks can be identified by the interlocking appearance of the crystals in them. Typical igneous rocks do not have a layered texture, but exceptions exist. For example, in large bodies of igneous rock, relatively thick crystals that are made early can sink to the bottom of the magma, and less thick layers of crystals that are made later can accumulate on top. Igneous rocks can form deep within the Earth or at the surface of the Earth in volcanoes.
In general, igneous rocks that form deep within the Earth have large crystals that indicate a longer period of time during which the magma cools. Igneous rocks that form at or near the surface of the Earth, such as volcanic igneous rocks, cool quickly and contain smaller crystals that are difficult to see without magnification. Obsidian, also called volcanic glass, cools down so fast that no crystals are made. Nevertheless, obsidian is considered to be an igneous rock.
Igneous rocks are classified on the basis of how much minerals there are and the size of the crystals in the rock. Extrusive igneous rocks have small crystals and crystallize at or near the Earth’s surface. Intrusive igneous rocks cool slowly below the Earth’s surface and have larger crystals. Rocks made up of thick, dark-colored minerals like olivine, pyroxene, amphibole, and plagioclase are called mafic igneous rocks.
Light-colored, less thick minerals, including quartz, mica, and feldspar are called felsic igneous rocks. Common igneous rocks include the felsic igneous rocks granite and rhyolite, and the mafic igneous rocks gabbro and basalt. Granite is an intrusive igneous rock that includes large crystals of the minerals quartz, feldspar, mica, and amphibole that form deep within the Earth. Rhyolite includes the same minerals, but forms as extrusive igneous rock near the surface of the Earth or in volcanoes and cools quickly from magma or lava, so its crystals are difficult to observe with the naked eye.
Similarly, gabbro is more coarse-grained than basalt and made deeper down in the Earth, but both rocks include the minerals pyroxene, feldspar, and olivine. Fabulous exposures of igneous rocks occur in the volcanoes of Hawaii, volcanic rocks of Yellowstone National Park are located in Wyoming, Idaho, Montana, in Lassen Volcanic National Park and Yosemite National Park in California. Sedimentary rocks are those made of grains of preexisting rocks or organic material that, in most cases, have been eroded, deposited, compacted, and cemented together. They typically form at the surface of the Earth as sediment moves as a result of the action of wind, water, ice, gravity, or a combination of these.
Sedimentary rocks also form as chemicals precipitate from seawater, or through accumulation of organic material such as plant debris or animal shells. Common sedimentary rocks include shale, sandstone, limestone, and conglomerate. Sedimentary rocks typically have a layered appearance because most sediments are deposited in horizontal layers and are buried beneath later deposits of sediments over long periods of time. Sediments deposited rapidly, however, tend to be poorly layered if layers are visible at all.
Sedimentary rocks are made in many different environments at the surface of the Earth. Eolian, or wind blown, sediments can accumulate in deserts. Rivers carry sediments and deposit them along their banks or into lakes or oceans. Glaciers make unusual deposits of a wide variety of sediments that they pick up as the glacier expands and moves; glacial deposits are well exposed in the northern United States. Sediments can travel in currents below sea level to the deepest parts of the ocean floor.
Secretion of calcium carbonate shells by reef-building organisms produce large quantities of limestone. Evaporation of seawater has resulted in the formation of widespread layers of salt and gypsum. Swamps rich in plants can produce coal if organic material accumulates and is buried before aerobic bacteria can destroy the dead plants. Sedimentary rocks are classified on the basis of the sizes of the particles in the rock and the composition of the rock.
Clastic sedimentary rocks comprise fragments of preexisting rocks and minerals. Chemical precipitates are sedimentary rocks that are made by precipitation of minerals from seawater, salt lakes, or mineral-rich springs. Organic sedimentary rocks formed from organic matter or organic activity, such as coal and limestone made by reef-building organisms like coral. Grain sizes in sedimentary rocks range from fine clay and silt to sand to boulders.
The sediment in a sedimentary rock reflects its environment of deposition. For example, wind-blown sand grains commonly is evidence of abrasion of their surfaces as a result of colliding with other grains. Sediments transported long distances tend to decrease in size and are more rounded than sediment deposited near their precursor rocks because of wearing against other sediments or rocks. Large or heavy sediments tend to wear out of water or wind if the energy of the water or wind is insufficient to carry the sediments.
Sediments deposited rapidly as a result of slides or slumps tend to include a larger range of sediment sizes, from large boulders to pebbles to sand grains and flakes of clay. Such rocks are called conglomerate. Along beaches, the rhythmic activity of waves moving sediment back and forth produces sandstones in which the grains are well rounded and of similar size. Glaciers pick up and carry a wide variety of sediments and often scratch or scrape the rocks over which they travel.
Sedimentary rocks are the only rocks in which fossils can be preserved because at the elevated temperatures and pressures in which igneous and metamorphic rocks form, fossils and organic remnants are ruined. The presence of fossils and the types of fossil organisms in a rock provide clues about the environment and age of sedimentary rocks. For example, fossils of human beings are not present in rocks older than approximately two million years because humans did not exist before then. Similarly, dinosaur fossils do not occur in rocks younger than about 65 million years because dinosaurs became extinct at that very time.
Fish fossils in sedimentary rock indicate that the sediments that make up the rock were deposited in a lake, river, or marine environment. By establishing the environment of the fossils in a rock, scientists learn more about the conditions under which the rock formed.
Spectacular exposures of sedimentary rocks include the Grand Canyon which is in Arizona, the eolian sandstones of Zion National Park which is in Utah, the limestones of Carlsbad National Park which is in New Mexico, and glacial features of Voyageurs National Park which is in Minnesota. Metamorphic rocks are named for the process of change that affects rocks. The changes that make metamorphic rocks usually include rises in the temperature (generally to 392°F) and the pressure of a precursor rock, which can be igneous, sedimentary, or metamorphic, to a degree that the minerals in the rock are no longer stable. The rock might change in mineral content or appearance, or even both. Clues to identifying metamorphic rocks include the presence of minerals such as mica, amphibole, staurolite, and garnet, and layers in which minerals are aligned as a result of pressure applied to the rock.
Common metamorphic rocks include slate, schist, and gneiss. Metamorphic rocks commonly are made in mountains such as the Appalachian Mountains, parts of California, and the ancient, eroded metamorphic rocks in the Llano Uplift of central Texas. Metamorphic rocks are classified depending on their constituent minerals and texture. Foliated metamorphic rocks are those that have a layered texture. In foliated metamorphic rocks, elongate or platy minerals such as mica and amphibole become aligned as a result of pressure on the rock. Foliation can range from alternating layers of light and dark minerals typical of gneiss to the seemingly perfect alignment of platy minerals in slate.
Some metamorphic rocks aren’t foliated and have a massive texture devoid of layers. Mineralogy of metamorphic rocks reflects the mineral content of the precursor rock and the pressure and temperature at which metamorphism occurs. As sediments undergo metamorphism, the layers of sediment can be folded or become more pronounced as pressure on the rock increases. Elongate or platy minerals in the rock tend to become aligned in the same direction.
For example, when shale metamorphoses to slate, it becomes easier to split the well-aligned layers of the slate into thin, flat sheets. This property of slate makes it an attractive roofing material. Marble-metamorphosed limestone typically does not have the pronounced layers of slate, but is used for flooring and sculptures.
Metamorphism of igneous rocks can cause the different minerals in the rocks to separate into layers. When granite metamorphoses into gneiss, layers of light-colored minerals and dark-colored minerals form. As with sedimentary rocks, elongate or platy minerals become well-aligned as pressure on the rock increases.
As sediments undergo metamorphism, the layers of sediment can be folded or become more pronounced as pressure on the rock increases. Elongate or platy minerals in the rock tend to become aligned in the same direction. For example, when shale metamorphoses to slate, it becomes easier to split the well-aligned layers of the slate into thin, flat sheets. This property of slate makes it an attractive roofing material.
Marble-metamorphosed limestone-typically does not have the pronounced layers of slate, but is used for flooring and sculptures. Metamorphism of igneous rocks can cause the different minerals in the rocks to separate into layers. When granite metamorphoses into gneiss, layers of light-colored minerals and dark-colored minerals are made. As with sedimentary rocks, elongate or platy minerals become well-aligned as pressure on the rock increases.
It is possible for metamorphic rocks to change into other metamorphic rocks. In some regions, especially areas where mountain building is taking place, it is not unusual for several episodes of change to affect rocks. It can be difficult to unravel the effects of each episode of metamorphism. The word igneous comes from the Latin word ignis which means of fire. Sedimentary rocks make layers at the bottoms of oceans and lakes.
Layers of sedimentary rocks are called strata.
I got this photo at https://www.hydroponicsnewyorkcity.com/wp-content/uploads/2014/02/river-rocks.jpg but originally Google Images.
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Hi there! I decided to research about cupcakes because I was reading a fictional cupcake book. Hope you enjoy the cupcake facts!
The cupcake evolved in the United States in the 19th century, and it was revolutionary because of the amount of time it saved in the kitchen. There was a shift from weighing out ingredients when baking to measuring out ingredients. According to the Food Timeline Web, food historians have yet to pinpoint exactly where the name of the cupcake originated.
There are two theories: one, the cakes were originally cooked in cups and two, the ingredients used to make the cupcakes were measured out by the cup. In the beginning, cupcakes were sometimes called “number” cakes, because they were easy to remember by the measurements of ingredients it took to create them: One cup of butter, two cups of sugar, three cups of flour, four eggs, one cup of milk, and one spoonful of soda. Clearly, cupcakes today have expanded to a wide variety of ingredients, measurements, shapes, and decorations – but this was one of the first recipes for making what we know today as cupcakes.
Cupcakes were convenient because they cooked much quicker than larger cakes. When baking was down in hearth ovens, it would take a long time to bake a cake, and the final product would often be burned. Muffin tins, also called gem pans, were popular around the turn of the 20th century, so people started created cupcakes in tins.
Since their creation, cupcakes have become a pop culture trend in the culinary world. They have spawned dozens of bakeries devoted entirely to them. While chocolate and vanilla remain classic favorites, fancy flavors such as raspberry meringue and espresso fudge can be found on menus.
There are cookbooks, blogs, and magazines specifically dedicated to cupcakes. Icing, also called frosting in the United States, is a sweet often creamy glaze made of sugar with a liquid, such as water or milk, that is often enriched with ingredients such as butter, egg whites, cream cheese, or flavorings. It is used to cover or decorate baked goods.
Elizabeth Raffald documented the first recipe for icing in 1769 in the Experienced English Housekeeper, according to the Food Timeline. The simplest icing is a glace icing, containing powdered sugar and water. This can be flavored and colored as desired, for example, by using lemon juice in place of the water.
More complicated icings can be made by beating fat into powdered sugar (as in buttercream), by melting fat and sugar together, by using egg whites (as in royal icing), and by adding other ingredients such as glycerin (as in fondant). Some icings can be made from combinations of sugar and cream cheese or sour cream, or by using ground almonds (as in marzipan). The first mention of the cupcake can be traced as far back as 1796, when a recipe notation of “a cake to be baked in small cups” was written in American Cookery by Amelia Simmons.
The earliest documentation of the term cupcake was in ‘Seventy-five Receipts for Pastry, Cakes, and Sweetmeats’ in 1828 in Eliza Leslie’s Receipts cookbook. In the early 19th century, there were two different uses for the name cup cake or cupcake. In previous centuries, before muffin tins were widely available, the cakes were often baked in individual pottery cups, ramekins, or molds and took their name from the cups they were baked in.
This is the use of the name that has remained, and the name of “cupcake” is now given to any small cake that is about the size of a teacup. The name “fairy cake” is a fanciful description of its size, which would be appropriate for a party of diminutive fairies to share. While English fairy cakes vary in size more than American cupcakes, they are traditionally smaller and are rarely topped with elaborate icing.
The other kind of “cup cake” referred to a cake whose ingredients were measured by volume, using a standard-sized cup, instead of being weighed. Recipes whose ingredients were measured using a standard-sized cup could also be baked in cups; however, they were more commonly baked in tins as layers or loaves. In later years, when the use of volume measurements was firmly established in home kitchens, these recipes became known as 1234 cakes or quarter cakes, so called because they are made up of four ingredients: one cup of butter, two cups of sugar, three cups of flour, and four eggs.
They are plain yellow cakes, somewhat less rich and less expensive than pound cake, due to using about half as much butter and eggs compared to pound cake. The names of these two major classes of cakes were intended to signal the method to the baker; “cup cake” uses a volume measurement, and “pound cake” uses a weight measurement. Cupcakes have become more than a trend over the years, they’ve become an industry!
Paper baking cups first hit U.S. markets after the end of the World War II. An artillery manufacturer called the James River Corporation began manufacturing cupcake liners for U.S. markets when its military markets began to diminish. By 1969, they consolidated business as a paper company and left artillery manufacturing behind.
During the 1950s, the paper baking cup gained popularity as U.S. housewives purchased them for convenience. Their flexibility grew when bakers realized that they could bake muffins as well as cupcakes in the baking cups. The modern idea of the cupcake is probably different from the historical origin of the phrase.
Imagine what it would be like being a cook in 19th-century Britain or North America. When food historians approach the topic of cupcakes, they run into a gray area in which the practice of making individual cup-sized cakes can become confused with the convention of making cakes with cup-measured ingredients. The notion of baking small cakes in individual containers probably began with the use of clay or earthenware mugs.
It could have been a way to use up extra batter; to make the most efficient use of a hot oven by placing small ramekins, or little baking dishes, in unused spaces; or to create an evenly baked product fast when fuel was in short supply. Early in the 20th century, the advent of multi-cupcake molded tins brought modest mass production methods to cupcake making, and a modern baking tradition was born. Cakes in some form have been around since ancient times, and today’s familiar round cakes with frosting can be traced back to the 17th century, made possible by advances in food technology such as: better ovens, metal cake molds and pans, and the refinement of sugar.
I got it at storify.com but I originally got it at Google Images.
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