Table of Contents
BEST IELTS General Reading Test 480
IELTS GENERAL READING TEST 480 – PASSAGE – 1
IELTS GENERAL READING TEST – 480
READING PASSAGE – 1
Foam
Foam is an entity formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films separating the regions of gas. Soap foams are also known as suds. Solid foams can be closed-cell or open-cell. In closed-cell foam, the gas forms discrete pockets, each completely surrounded by the solid material. In open-cell foam, gas pockets attach to each other. A bath sponge is an example of an open-cell foam: water easily flows through the entire structure, displacing the air.
A camping mat is an example of a closed-cell foam: gas pockets are sealed from each other so the mat cannot soak up water. Foams are examples of dispersed media. In general, gas is present, so it divides into gas bubbles of diverse sizes (i.e., the material is polydisperse) separated by liquid regions that may form films, thinner and thinner when the liquid phase pipes out of the system films. When the principal scale is small, i.e., for a very fine foam, this dispersed medium can be considered a type of colloid.
Foam can also refer to something that is analogous to foam, such as quantum foam, polyurethane foam (foam rubber), XPS foam, polystyrene, phenolic, or many other manufactured foams.
IELTS General Reading Test
One scale is the bubble: material foams are typically disordered and have a variety of bubble sizes. At larger sizes, the study of idealized foams is closely linked to the mathematical problems of minimal surfaces and three-dimensional tessellations, also called honeycombs. The Weaire-Phelan structure is considered the best possible unit cell of a perfectly ordered foam, while Plateau’s laws describe how soap-films form structures in foams. At lower scale than the bubble is the thickness of the film for metastable foams, which can be considered a web of unified coatings called lamellae. Ideally, the lamellae connect in triads and radiate 120° outward from the connection points, known as Plateau borders.
An even lower scale is the liquid-air interface at the surface of the film. Most of the time this interface is stabilized by a layer of amphiphilic structure, often made of surfactants, particles (Pickering emulsion), or more complex associations. Solid foams, both open-cell and closed-cell, are considered as a sub-class of cellular structures. They often have deficient nodal connectivity as compared to other cellular structures like honeycombs and truss lattices, and thus, their failure mechanism is dominated by bending of members. Low nodal connectivity and the resulting failure mechanism ultimately led to their inferior mechanical strength and stiffness compared to honeycombs and truss lattices.
IELTS General Reading Test
Questions 1-7
Do the following statements agree with the information given in the Reading Passage?
TRUE – If the statement agrees with the information
FALSE – If the statement contradicts the information.
NOT GIVEN – If there is no information on this.
1. Commonly, foams encompass hefty capacities of gas with slender layers splitting the sections of gas.
2. Gas forms separate pouches entirely and individually encircled by solid material in case of solid closed-cell foams.
3. Liquids do not effortlessly pass through an open-cell foam.
4. Closed-cell foam is denser and more robust than open-cell foam.
5. The Weaire-Phelan structure is believed to be the most optimal unit cell of a flawlessly well-organized foam.
6. Metastable foams comprise a mesh of amalgamated layers called lamellae.
7. Solid foams have boosted nodal connectivity than honeycombs.
IELTS General Reading Test
Read the text below and answer questions 8-14.
GRANITE
Granite is a coarse-grained igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground. It is common in the Earth’s continental crust, where it is found in various kinds of igneous intrusions. These range in size and are found in watercourses only a few inches across to batholiths exposed over hundreds of square kilometres. Granite is typical of a larger family of granitic rocks that are composed mostly of coarse-grained quartz and feldspars in varying proportions.
These rocks are classified by the relative percentages of quartz, alkali feldspar, and plagioclase (the QAPF classification), with true granite representing granitic rocks rich in quartz and alkali feldspar. Most granitic rocks also contain mica or amphibole minerals, though a few known as leucogranites contain almost no dark minerals.
IELTS General Reading Test
Granite is nearly always massive, tough with beautiful fascia. These properties have made granite a widespread construction stone throughout human history. The word “granite” comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a completely crystalline rock. Granitic rocks mainly consist of feldspar, quartz, mica, and amphibole minerals, which form an interlocking, somewhat equigranularity matrix of feldspar and quartz with scattered darker biotite mica and amphibole (often hornblende) peppering the lighter colour minerals.
Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-coloured, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of ites can be predominantly white, pink, or grey in colour, depending on their migranitoids. Granneralogy.
IELTS General Reading Test
The alkali feldspar in granites is typically orthoclase or microcline and is often perthitic. The plagioclase is typically sodium-rich oligoclase. Phenocrysts are usually alkali feldspar. Granitic rocks are classified according to the QAPF diagram for coarse grained plutonic rocks and are named according to the percentage of quartz, alkali feldspar (orthoclase, sanidine, or microcline) and plagioclase feldspar on the A-Q-P half of the diagram. True granite (according to modern petrologic convention) contains between 20% and 60% quartz by volume, with 35% to 90% of the total feldspar consisting of alkali feldspar.
Granitic rocks poorer in quartz are classified as syenites or monzonites, while granitic rocks subjugated by plagioclase are classified as granodiorites or tonalites. Granitic rocks with over 90% alkali feldspar are classified as alkali feldspar granites. Granitic rock with more than 60% quartz, which is uncommon, is classified simply as quartz-rich granitoid or, if composed almost entirely of quartz, as quartzolite. True granites are further classified by the percentage of their total feldspar that is alkali feldspar.
IELTS General Reading Test
Granites whose feldspar is 65% to 90% alkali feldspar are syenogranites, while the feldspar in monzogranite is 35% to 65% alkali feldspar. A granite containing both muscovite and biotite micas is called a binary or two-mica granite. Two-mica granites are typically high in potassium and low in plagioclase and are usually S-type granites or A-type granites, as described below.
Questions 8-14
Write no more than THREE WORDS and/or numbers for each answer.
8. Granite is made from magma with extraordinary volume of some materials that coagulates …………………….
9. Granitic rocks profuse in ……………………. and ……………………. signifies authentic granite.
IELTS General Reading Test
10. Rare granitic rocks embrace virtually zero …………………….
11. Throughout human past, granite has been used because of its robustness, gigantic size and ……………………. facade.
12. The granite rock gets its term from a Latin word, granum, which is another expression for …………………….
13. Granitic rocks containing huge quantities of plagioclase are categorized as …………………….
14. Accurate granites are additionally characterised by the proportion of their overall …………………….
IELTS General Reading Test
IELTS General Reading Test
ANSWERS
1. TRUE
2. TRUE
3. FALSE
4. NOT GIVEN
5. TRUE
6. TRUE
7. FALSE
8. UNDERGROUND
9. QUARTZ, ALKALI FELDSPAR
10. DARK MINERALS
11. BEAUTIFUL
12. A GRAIN
13. GRANODIORITES / TONALITES
14. FELDSPAR / ALKALI FELDSPAR
IELTS General Reading Test