The Structure And Properties Of Surfactants

The Structure And Properties Of Surfactants Surfactants are compounds that lower the surface tension of a liquid, allowing easier spreading, and lowering of the interfacial tension between two liquids, or between a liquid and a solid. Surfactants may act as: Detergents Wetting agents Emulsifiers Foaming agents Dispersants STRUCTURE OF SURFACTANT Figure 1Surfactant molecule possess a dualistic character.This arises from the combination of a hydrophobic (water-rejecting) and a hydrophilic (water-preferring) group in one molecule.In a classical surfactant,the hydrophobic part usually consists of one or more hydrocarbon chains sometimes with various degrees of unsaturation and branching.However,the apolar part may also be partly or completely fluorinated or may be composed of a siloxane chain.The size and length of the hydrocarbon may vary considerably,but it must consists of atleast 8 carbon atoms.For the hydrophilic part(usually called the headgroup),there is a wide range of possible structures(Table1.1).The hydrophilic part can either be ionic or dipolar depending on whether the headgroup has a net charge or not. [1] PROPERTIES OF SURFACTANTS They enable the cleaning solution to fully wet the surface being cleaned so that dirt can be readily loosened and removed. They clean greasy, oily, particulate-, protein-, and carbohydrate-based stains. They are instrumental in removing dirt and in keeping them emulsified, suspended, and dispersed so they dont settle back onto the surface being cleaned. Surfactants are one of the major components of cleaning products and can be regarded as the workhorses: they do the basic work of breaking up stains and keeping the dirt in the water solution to prevent re-deposition of the dirt onto the surface from which it has just been removed. Surfactants disperse dirt that normally does not dissolve in water. As anyone who uses oil based dressings in the kitchen knows, oil and water do not mix unless shaken vigorously in the bottle. They separate almost immediately afterwards. The same is true when washing your dishes or clothes. With the addition of surfactants, oil, which normally does not dissolve in water, becomes dispersible and can be removed with the wash water. . CLASSIFICATION OF SURFACTANTS It is generally classified in 4 basic types depending upon the nature of the head group: Anionic Non anionic Cationic Amphoteric or zwitter-ionic Anionic Surfactants In solution, the head is negatively charged. This is the most widely used type of surfactant for laundering, dishwashing liquids and shampoos because of its excellent cleaning properties and high sudsing potential. The surfactant is particularly good at keeping the dirt away from fabrics, and removing residues of fabric softener from fabrics. Anionic surfactants are particularly effective at oily soil cleaning and oil/clay soil suspension. Still, they can react in the wash water with the positively charged water hardness ions (calcium and magnesium), which can lead to partial deactivation. The more calcium and magnesium molecules in the water, the more the anionic surfactant system suffers from deactivation. To prevent this, the anionic surfactants need help from other ingredients such as builders (Ca/Mg sequestrants) and more detergent should be dosed in hard water. The most commonly used anionic surfactants are alkyl sulphates, alkyl ethoxylate sulphates and soaps. Non anionic Surfactants These surfactants do not have an electrical charge, which makes them resistant to water hardness deactivation. They are excellent grease removers that are used in laundry products, household cleaners and hand dishwashing liquids. Most laundry detergents contain both non-ionic and anionic surfactants as they complement each others cleaning action. Non-ionic surfactants contribute to making the surfactant system less hardness sensitive. The most commonly used non-ionic surfactants are ethers of fatty alcohols Cationic Surfactants In solution, the head is positively charged. There are 3 different categories of cationics each with their specific application: In fabric softeners and in detergents with built-in fabric softener, cationic surfactants provide softness. Their main use in laundry products is in rinse added fabric softeners, such as esterquats, one of the most widely used cationic surfactants in rinse added fabric softeners. An example of cationic surfactants is the esterquat. In laundry detergents, cationic surfactants (positive charge) improve the packing of anionic surfactant molecules (negative charge) at the stain/water interface. This helps to reduce the dirtl/water interfacial tension in a very efficient way, leading to a more robust dirt removal system. They are especially efficient at removing greasy stains. An example of a cationic surfactant used in this category is the mono alkyl quaternary system. In household and bathroom cleaners, cationic surfactants contribute to the disinfecting/sanitizing properties. Amphoteric Surfactants These surfactants are very mild, making them particularly suited for use in personal care and household cleaning products. They can be anionic (negatively charged), cationic (positively charged) or non-ionic (no charge) in solution, depending on the acidity or pH of the water. They are compatible with all other classes of surfactants and are soluble and effective in the presence of high concentrations of electrolytes, acids and alkalis. These surfactants may contain two charged groups of different sign. Whereas the positive charge is almost always ammonium, the source of the negative charge may vary (carboxylate, sulphate, sulphonate). These surfactants have excellent dermatological properties. They are frequently used in shampoos and other cosmetic products, and also in hand dishwashing liquids because of their high foaming properties. An example of an amphoteric/zwitterionic surfactant is alkyl betaine. Figure 2 Figure 3 SURFACE TENSION Water has many unusual properties as a result of its ability to hydrogen bond. For example, the density of ice is less than that of the liquid and the predicted boiling point is almost 200 degrees C higher than it would be without hydrogen bonding. The water molecules at the surface of water are surrounded partially by air and partially by water. These surface molecules would be much more stable if they could be in the interior of the liquid where all their hydrogen bonds could be fulfilled (cohesion). Therefore, water normally tends to have the smallest surface possible, i.e. it has a high surface tension, in order to achieve the lowest possible energetic state. If a solid material more dense than water is placed on the surface of water, what happens next depends on the nature of the material. If the material is hydrophilic (water loving) it has a surface to which water is attracted. The adhesion of water to the surface of this material coats the surface of the object with water, reduces the surface tension, and causes the object to sink. If the solid object is hydrophobic (water fearing),the unfavorable interactions between the water surface and the object make it difficult to wet the surface. Two forces now come into play the energy it would take to overcome this repulsion and the force of gravity. If the force of gravity is strong enough, it will prevail and the object will sink (assuming that the object has a density greater than water). If the gravitational force is less than the surface tension then the object will float on the surface of the water. Surface tension is what permits water striders and other insects to walk across the surface of water and what enables a needle to float. Of course, the critical feature here is the amount of force per unit area put a needle into water end-on instead sideways and the needle will immediately sink. SURFACTANT FUNCTION Surfactants are also referred to as wetting agents and foamers. Surfactants lower the surface tension of the medium in which it is dissolved. By lowering this interfacial tension between two media or interfaces (e.g. air/water, water/stain, stain/fabric) the surfactant plays a key role in the removal and suspension of dirt. The lower surface tension of the water makes it easier to lift dirt and grease off of dirty dishes, clothes and other surfaces, and help to keep them suspended in the dirty water. The water-loving or hydrophilic head remains in the water and it pulls the stains towards the water, away from the fabric. The surfactant molecules surround the stain particles, break them up and force them away from the surface of the fabric. They then suspend the stain particles in the wash water to remove them. Surfactants can work in three different ways: roll-up, emulsification, and solubilization. Roll-up mechanism The surfactant lowers the oil/solution and fabric/solution interfacial tensions and in this way lifts the stain of the fabric. Figure 3 Emulsification The surfactant lowers the oil-solution interfacial tension and makes easy emulsification of the oily soils possible. Figure 4 Solubilization Through interaction with the micelles of a surfactant in a solvent (water), a substance spontaneously dissolves to form a stable and clear solution How can surfactants prevent dirt from being re-deposited? Surfactants have a vital role to play in preventing the re-deposition of soils like greasy, oily stains and particulate dirt on the surface or fabric from which they have just been removed. This works by electrostatic interactions and steric hindrance. Electrostatic interactions Anionic surfactants are adsorbed on both the surface of the dirt which is dispersed in the detergent solution, and the fabric surface. This creates a negative charge on both surfaces, causing electrostatic repulsions. This repulsion prevents the soil from re-depositing on the fabric. In the presence of hardness, however, this mechanism acts like a bridge between the suspended soil and the fabric. This is another reason why hardness sequestrants (a chemical that promotes Ca/Mg sequestration) are often used in detergents. Steric hindrance: Non-ionic surfactants like alcohol ethoxylates also adsorb on the dirt. Their long ethoxylated chains extend in the water phase and prevent the dirt droplets or particles from uniting and from depositing onto the fabric surface.Dirt is present in solution. The non-ionic surfactants adsorb to the dirt particles.Their long hydrophilic heads extend in the water phase and as a result prevent the dirt particles/droplets from uniting and from re-depositing onto fabrics. [2] SURFACTANT USES There are many uses of surfactant in different industries and different fields. Some of them are discussed below: Use of Surfactant in Detergents Surfactants are literally Surface Acting Agents. They are called this because they act to reduce the surface tension of a liquid, especially water. They are large molecules with two distinct parts. First there is a head which is hydrophilic. This means that it is attracted to water and soluble in water, usually because it has a positive or negative charge. The other part of the surfactant is the tail which is hydrophobic, meaning it is repelled by water. The tail is also lipophilic which means that it is soluble in organic solvents particularly oils and fats or lipids. It is this mixed structure which gives a surfactant its properties. When added to water the surface tension of water is reduced. The surface tension of water is caused by the hydrogen bonds which form between the slight charges on different parts of the water molecule (for further information see the water article). Surfactants break up these hydrogen bonds by remaining at the surface, their heads dissolved in the water but their tails extending out of the water, repelled by it. When the surfactant concentration increases sufficiently, micelles are formed. These are spheres of surfactant with all the heads on the outside protecting all the tails within.[3] Use of Surfactant in Cosmetics Shampoos and soaps clean by the use of surfactants (surface active agents). Surfactant molecules have both fat soluble (lipophilic) and water-soluble (hydrophylic) parts. The lipophilic part of the molecule sticks to oil and dirt, and the hydrophilic part allows water to then carry away the otherwise water-insoluble grime. Washing-up detergents work in the same way, although it isnt generally advisable to wash your hair with dishwashing liquid they are formulated to remove thick grease from plates, not to gently clean your hair! [4] Use of Surfactants to remove solvent-based inks from plastic films There is substantial economic and environmental incentive to remove the ink (deink) from heavily printed plastic films so that the plastic can be reused to produce clear films. In this study, polyethylene films printed with solvent-based ink were deinked using surfactants under a variety of conditions. Water without surfactant does not deink the solvent-based ink from plastic films over a pH range of 3 to 12. In common with earlier studies of water-based inks, it is found that solutions of cationic surfactants are the most effective for deinking of solvent-based ink but a pH of at least 11 is required. Presoaking of plastic film in aqueous solution of cationic surfactant increases the level of deinking. Limited studies performed with a pilot-size paper deinking apparatus on solvent-based ink removal indicates that the deinking of plastic film using surfactant solutions is technically feasible. [5] Pulmonary Surfactants and Therapeutic uses, including Pulmonary Lavage The present invention discloses useful surfactant molecules including polypeptides, proteins, and a variety of other organic molecules, as well as methods of making and using same. Surfactant compositions, including liposomal surfactant compositions, are also disclosed. Use of the surfactant molecules of the present invention in pulmonary lavage procedures for a variety of therapeutic applications is also disclosed, including the treatment of respiratory distress syndrome; the removal of inflammatory exudate from inflamed lung tissues; and the treament of meconium aspiration syndrome in infants. [6] Adsorption of non-petroleum base Surfactant on reservoir rock SURFACTANT molecules adsorb well to solid interfaces such as the porous media found in petroleum reservoirs.The adsorbed surfactant layer represents both an additional resistance to flow as well as loss of surfactant properties and is therefore, of fundamental importance in the enhanced oil recovery (EOR) process that involves the flow of surfactant solution through porous media.According to Austad and Milter1, chemical flooding of oil reservoirs is one of the most successful methods to enhance oil recovery from depleted reservoirs at low pressure. [7] Use of Surfactant in Neonates Surfactant replacement therapy has become an established treatment for neonatal respiratory distress syndrome (RDS). This article reviews the current evidence for the various practices regarding the use of surfactant in this condition, looking at surfactant type, timing of the first dose, size and frequency of the dose and the need for further doses. As the use of surfactant is expanding into other lung diseases in adults as well as children, we also review those neonatal conditions where surfactant may be of benefit and summarize the evidence published to date supporting its use in these conditions. [8] Surfactant as Antifog Many of the cheaper anti-fogs are made of surfactants like glycerin (soap) and water or alcohol combinations. That works for a very short period. Better anti-fogs usually contain advanced silicones but suffer from poor spreading. You have to rub them in and wipe off excess. [9] Surfactant as Fabric Softner Fabric softeners have long been used to soften fabric and prevent static cling. Available in dryer sheets or liquid form, fabric softeners are made up of surfactants or surface acting agents. It is these chemicals that create a softer, fluffier feel to your laundry. Surfactants contain chemicals with lubricating properties. These chemicals coat fabrics with a waxy film that lubricates them, causing them to feel smoother or fluffier. Its suggested that these lubricating chemicals also make ironing easier and reduce drying time and wrinkling. The lubricating properties of surfactants are a result of positive charges affecting negative charges. Surfactants are generally acidic and made up of positively charged particles. These positively charged particles attract the negatively charged particles within scratchy fabric. The negative charge is neutralized, creating a lower frictional resistance. Thus, there is less static cling and the fabric feels softer and less scratchy to touch. [10] Surfactant in Ski Waxes Once the ski is in motion, you are applying pressure and exerting friction, melting the snow, and creating a fine layer of water between your ski base and the snow. Control and maneuverability in skiing is derived from altering the structure of this water. Hertel wax systems perform a special process using an encapsulation process; tiny bits of surface-active agents formulated into the waxes interact with water, decreasing surface tension and friction, plus increasing control. The wax breaks up the water (snow) resulting in easier running, better control, added safety, and more fun. When commanded to turn, skis slide with ease. [11] Effect of oil soluble Surfactant in emulsions stabilised by clay particles Although surfactants and particles are often mixed together in emulsions, the contribution of each species to the stabilisation of the oil-water interface is poorly understood. We report the results of investigations into the formation of emulsions from solutions of surfactant in oil and aqueous suspensions of laponite. Depending on the salt concentration in the aqueous suspensions, the laponite dispersed as individual disc-shaped particles, 30 nm in diameter, or flocculated into aggregates tens of micrometres in diameter. At the concentrations studied, the flocculated particles alone stabilized oil-in-water emulsions. Synergistic interactions between the particles and octadecylamine at the oil-water interface reduced the average emulsion drop size, while antagonistic interactions with octadecanoic acid enhanced coalescence processes in the emulsions. The state of particle dispersion had dramatic effects on the emulsions formed. Measurements of the oil-water interfacial tension revea led the origins of the interactions between the surfactants and particles. [12] Surfactant in process for deinking of recycled paper A process for deinking recycled paper using a pressurized deinking module to separate ink from paper pulp stock. The addition of salts of imidazolinium based compounds with alkyl, alkenyl and amidoethyl side chains to the pulp slurry at the beginning of the pressurized deinking module cycle removes ink more effectively and results in a brighter recycled paper and an increase in yield of final paper stock. [13] Surfactant in Spermicides (NONOCYNOL-9) The most common active ingredient of spermicides is Nonoxynol 9. Spermicides containing Nonoxynol-9 are available in many forms, such as jelly (gel), films, and foams. Nonoxynol-9, sometimes abbreviated as N-9, is an organic compound that is used as a surfactant. It is a member of the nonoxynol family of nonionic surfactants. N-9 and related compounds are ingredients in various cleaning and cosmetic products. Its use is controversial because it may cause genital lesions. Nonoxynol-9s ability to kill microbes in vitro was initially taken as evidence that it might be effective at preventing STD transmission. However, more recent findings indicate that it may actually increase a persons risk of contracting STDs, especially if used frequently. This is because the chemical causes tiny abrasions inside the sensitive vaginal and anal walls. [14] Surfactant in Ferro Fluid:Magnetic Liquid Technology A ferrofluid is a stable colloidal suspension of sub-domain magnetic particles in a liquid carrier. The particles, which have an average size of about 100Ã… (10 nm), are coated with a stabilizing dispersing agent (surfactant) which prevents particle agglomeration even when a strong magnetic field gradient is applied to the ferrofluid. The surfactant must be matched to the carrier type and must overcome the attractive van der Waals and magnetic forces between the particles. The colloid and thermal stabilities, crucial to many applications, are greatly influenced by the choice of the surfactant. A typical ferrofluid may contain by volume 5% magnetic solid, 10% surfactant and 85% carrier. [15] Surfactant as Alkali Surfactant Polymers In the Alkaline Surfactant Polymer (ASP) process, a very low concentration of the surfactant is used to achieve ultra low interfacial tension between the trapped oil and the injection fluid/formation water. The ultra low interfacial tension also allows the alkali present in the injection fluid to penetrate deeply into the formation and contact the trapped oil globules. The alkali then reacts with the acidic components in the crude oil to form additional surfactant in-situ, thus, continuously providing ultra low interfacial tension and freeing the trapped oil. In the ASP Process, polymer is used to increase the viscosity of the injection fluid, to minimize channeling, and provide mobility control. Oil Chem Technologiess patented ORS and ORS-HF series surfactants are specifically formulated for each field to optimize the oil recovery. Crude oil characteristics, brine characteristics, bottom hole temperature, alkali, well history, and treatment design are considered to maximize the treatment results. [16] Other applications of surfactants are: In biochemistry, the practical as well as theoretical importance of surfactants may be illustrated with the following examples: Surfactants have allowed the investigation of molecular properties of membrane proteins and lipoproteins, acting as solubilizing agents and as probes for hydrophobic binding sites. The properties of surfactants, as well as further facts relevant to the particular experiments, must be carefully considered. Surfactants have successfully contributed to the purification of receptors in their active forms, such as the neuropeptide receptors and opiate receptors. All holoreceptor- complex and reaction- center isolations require the use of a surfactant in order to separate the integral protein systems from the rest of the membrane. Surfactants have been used in the investigation of the denaturation of bacteriorhodopsin and in thermal stability experiments of rhodopsin. The operations of exchange and removal of surfactants bound to membrane proteins are crucial and have been successfully applied to a wide variety of these proteins. The effects of surfactants on the function of membrane-bound enzymes such as cytochrome P-450 and (Na+ + K+)-ATPase have also been determined. Integral membrane proteins can be separated from hydrophilic proteins and identified as such in crude surfactant extracts of membrane or cells . Methods for the solubilization of low-density lipoproteins have advanced the understanding of the assembly, interconversion and molecular exchange processes with plasma lipoproteins. In electrophoresis, various techniques require the use of surfactants. The popular techniques of SDS-PAGE for the identification and subunit molecular weight estimation of proteins is based on a specific type of surfactant-protein interaction. 2D-PAGE uses SDS in one direction and Triton X-100 in the other. This technique has been used to identify proteins containing long hydrophobic regions and relies on the different binding ability of non-ionic surfactants to water-soluble and intrinsic membrane proteins. Isoelectric focusing, native electrophoresis and blotting are other electrophoretic techniques which may need surfactants for the solubilization or transfer of membrane proteins. In high performance liquid chromatography, common techniques such as ion-exchange HPLC, reversed-phase HPLC and sizeexclusion-HPLC may require surfactants to solubilize membrane proteins. Ionpair HPLC requires surfactants as reagents in order to achieve the separation conditions (ionpairing). Affinity surfactants have been used as reversibly bound ligands in high performance affinity chromatography. Crystallization of membrane proteins was achieved using short chain surfactants, which are believed to shield the hydrophobic intermembrane part of the molecule. Thus the polar interactions betvveen individual molecules come into play, providing the stabilizing force in crystallization. Surfactants are also employed to promote the dissociation of proteins from nucleic acids on extraction from biological material. Further applications of surfactants in biochemistry are the solubilization of enzymes in apolar solvents via reversed micelles and the isolation of hydrophobic proteins. [17] CAPTION TO FIGURES: Figure 1-http://www.scienceinthebox.com/en_UK/glossary/popup-roll-up-mechanism.html Figure 2-http://www.scienceinthebox.com/en_UK/glossary/popup-emulsification.html Figure 3-http://www.caes.uga.edu/applications/publications/files/html/B1319/images/Figure%202.jpg BOOK REFERREDFigure 4-http://www.inkline.gr/inkjet/newtech/tech/dispersion/surfactants.gif APPLIED SURFACTANTS:PRINCIPLES AND APPLICATIONS -BY THARWAT F. TADROS WILEY-WCH PUBLICATION

Academic History

I am currently enrolled in the Business School at Villanova University. My academic standing is good and I have maintained a grade point average of 3.62. I believe I am stable and the change I wish to make in my choice of universities is based on logic and not a whim. I have not transferred before, so this will be a first.My university experience has not had any significant breaks; it flows in an unbroken line from my initial enrollment to the present time. I suffered a few hiccoughs alone the way, but I have persevered, and I managed to rise from the bottom of my seventh year class in Shanghai to the rank of number one in ESL.I was in an alien environment and it was no small matter to adapt to the different culture I found in Shanghai. Despite my lack of height I managed to excel in varsity basketball as well. I think it is worth noting that I am not a native English speaker, but I took my deficiency in the language as a challenge and managed to thrive. I am proud of the fact that I quickly moved from ESL to 1B Class in the British system, which is equivalent to AP.I am steadfast in my resolve and I have not changed career paths. I have found that there is a lack of cultural diversity at Villanova. I initially did not realize the lack was so profound. I had erroneously assumed that matters would balance themselves and I would find there was more diversity than I first saw.This proved not to be the case, however. I believe that the university experience is not one-dimensional. I think a university education is only complete when the student is rounded into a productive member of society instead of just being grounded in the basics of his or her major.I was once accepted at the University of Washington, and I have every hope that the university will look favorably on my application once more, permitting me to correct my mistake and allowing me to attend the University of Washington as I should have done in the first place.  Major and Career Goals:It is my inte ntion to major in Finance. I believe that the university is home to one of the best and most extensive business programs in the United States. I am Taiwanese by birth and spent most of my life in Shanghai, which has a reputation as being the future â€Å"Finance Center† for all of Asia.Early on I came to realize the importance of knowledge in financial dealings, with money management being particularly important.   I spent my high school years in pursuit of learning all I could on the subject of economics, calculus and other math related subjects. Business is the life-blood of my country’s economy.I am savvy enough to understand that capital is the engine that drives business. It is as the old Chinese proverb says, â€Å"Money is not everything, but without money nothing can be done.† But I also realize that money alone is not enough. Having funding is only the first step toward a successful business. The entrepreneur must have the knowledge and associated ski lls to handle turning a profit and ensuring that the business operations run smoothly.Money management is the second part of the equation in producing success. I believe that a degree from the University of Washington will go far toward ensuring that I will have this knowledge and the necessary skills. I have expectations that a degree from your university’s Finance program will benefit me greatly as I scale the corporate ladder.Further, I believe that a University of Washington education will help me fulfill my avowed goal of becoming a specialist in investment analysis. My intention is to become an investment or business analyst in the United States, with an eye toward the Wall Street Journal. I have a fervent believe that I can attain this dream if I am blessed and fortunate enough to be accepted at the University of Washington.Cultural Understanding:The University of Washington is culturally diverse, and being Taiwanese, I am acutely aware of how important that can be for a student, irrespective of his area of study. I look forward to the healthy interaction and social intercourse that will avail itself to me in the richer milieu of this university.I look forward to the exchange of ideas and the broadening effect that intercultural communication can bring. In essence I look forward to being able to share my culture and I look forward to the learning experience I will receive from the various cultures of my fellow students.I fully expect the school to pave the path which I will follow as I experience personal growth on the road to my ultimate goals. It is not a capricious decision, I have carefully studied my options and have chosen what I believe to be the most advantageous avenue for me.When considering the reputation which the university enjoys I feel confident that my acceptance into the business program will furnish me with the needed tools to accomplish my goal in this life. I expect to become a highly competent business analyst, but more, I ex pect to become a productive citizen, replete with the values that will enhance the fulfillment of my aspirations.I expect to become a valued alumnus, having been enriched by the university experience. This growth in personal values and mores is important to my sense of self worth, and will make me a more valuable member of society.It is my belief that the true excellence of any institution of higher learning lies in its ability to educate the whole person. A school becomes truly excellent by excelling in the programs that it offers as well as the values it inculcates in its students, which is how I see the University of Washington.

Chapter 5 Weasleys’ Wizard Wheezes

Harry spun faster and faster, elbows tucked tightly to his sides, blurred fireplaces flashing past him, until he started to feel sick and closed his eyes. Then, when at last he felt himself slowing down, he threw out his hands and came to a halt in time to prevent himself from falling face forward out of the Weasleys' kitchen fire. â€Å"Did he eat it?† said Fred excitedly, holding out a hand to pull Harry to his feet. â€Å"Yeah,† said Harry, straightening up. â€Å"What was it?† â€Å"Ton-Tongue Toffee,† said Fred brightly. â€Å"George and I invented them, and we've been looking for someone to test them on all summer†¦.† The tiny kitchen exploded with laughter; Harry looked around and saw that Ron and George were sitting at the scrubbed wooden table with two red-haired people Harry had never seen before, though he knew immediately who they must be: Bill and Charlie, the two eldest Weasley brothers. â€Å"How're you doing, Harry?† said the nearer of the two, grinning at him and holding out a large hand, which Harry shook, feeling calluses and blisters under his fingers. This had to be Charlie, who worked with dragons in Romania. Charlie was built like the twins, shorter and stockier than Percy and Ron, who were both long and lanky. He had a broad, good-natured face, which was weather-beaten and so freckly that he looked almost tanned; his arms were muscular, and one of them had a large, shiny burn on it. Bill got to his feet, smiling, and also shook Harry's hand. Bill came as something of a surprise. Harry knew that he worked for the wizarding bank, Gringotts, and that Bill had been Head Boy at Hogwarts; Harry had always imagined Bill to be an older version of Percy: fussy about rule-breaking and fond of bossing everyone around. However, Bill was – there was no other word for it – cool. He was tall, with long hair that he had tied back in a ponytail. He was wearing an earring with what looked like a fang dangling from it. Bill's clothes would not have looked out of place at a rock concert, except that Harry recognized his boots to be made, not of leather, but of dragon hide. Before any of them could say anything else, there was a faint popping noise, and Mr. Weasley appeared out of thin air at George's shoulder. He was looking angrier than Harry had ever seen him. â€Å"That wasn't funny Fred!† he shouted. â€Å"What on earth did you give that Muggle boy?† â€Å"I didn't give him anything,† said Fred, with another evil grin. I just dropped it†¦.It was his fault he went and ate it, I never told him to.† â€Å"You dropped it on purpose!† roared Mr. Weasley. â€Å"You knew he'd eat it, you knew he was on a diet -â€Å" â€Å"How big did his tongue get?† George asked eagerly. â€Å"It was four feet long before his parents would let me shrink it!† Harry and the Weasleys roared with laughter again. â€Å"It isn't funny!† Mr. Weasley shouted. â€Å"That sort of behavior seriously undermines wizard-Muggle relations! I spend half my life campaigning against the mistreatment of Muggles, and my own sons â€Å"We didn't give it to him because he's a Muggle!† said Fred indignantly. â€Å"No, we gave it to him because he's a great bullying git,† said George. â€Å"Isn't he, Harry?† â€Å"Yeah, he is, Mr. Weasley,† said Harry earnestly. â€Å"That's not the point!† raged Mr. Weasley. â€Å"You wait until I tell your mother -â€Å" â€Å"Tell me what?† said a voice behind them. Mrs. Weasley had just entered the kitchen. She was a short, plump woman with a very kind face, though her eyes were presently narrowed with suspicion. â€Å"Oh hello, Harry, dear,† she said, spotting him and smiling. Then her eyes snapped back to her husband. â€Å"Tell me what, Arthur?† Mr. Weasley hesitated. Harry could tell that, however angry he was with Fred and George, he hadn't really intended to tell Mrs. Weasley what had happened. There was a silence, while Mr. Weasley eyed his wife nervously. Then two girls appeared in the kitchen doorway behind Mrs. Weasley. One, with very bushy brown hair and rather large front teeth, was Harry's and Ron's friend, Hermione Granger. The other, who was small and red-haired, was Ron's younger sister, Ginny. Both of them smiled at Harry, who grinned back, which made Ginny go scarlet – she had been very taken with Harry ever since his first visit to the Burrow. â€Å"Tell me what, Arthur?† Mrs. Weasley repeated, in a dangerous sort of voice. â€Å"It's nothing, Molly,† mumbled Mr. Weasley, â€Å"Fred and George just – but I've had words with them -â€Å" â€Å"What have they done this time?† said Mrs. Weasley. â€Å"If it's got anything to do with Weasleys' Wizard Wheezes -â€Å" â€Å"Why don't you show Harry where he's sleeping, Ron?† said Hermione from the doorway. â€Å"He knows where he's sleeping,† said Ron, â€Å"in my room, he slept there last -â€Å" â€Å"We can all go,† said Hermione pointedly. â€Å"Oh,† said Ron, cottoning on. â€Å"Right.† â€Å"Yeah, we'll come too,† said George. â€Å"You stay where you are!† snarled Mrs. Weasley. Harry and Ron edged out of the kitchen, and they, Hermione, and Ginny set off along the narrow hallway and up the rickety staircase that zigzagged through the house to the upper stories. â€Å"What are Weasleys' Wizard Wheezes?† Harry asked as they climbed. Ron and Ginny both laughed, although Hermione didn't. â€Å"Mum found this stack of order forms when she was cleaning Fred and George's room,† said Ron quietly. â€Å"Great long price lists for stuff they've invented. Joke stuff, you know. Fake wands and trick sweets, loads of stuff. It was brilliant, I never knew they'd been inventing all that†¦Ã¢â‚¬  â€Å"We've been hearing explosions out of their room for ages, but we never thought they were actually making things,† said Ginny. â€Å"We thought they just liked the noise.† â€Å"Only, most of the stuff – well, all of it, really – was a bit dangerous,† said Ron, â€Å"and, you know, they were planning to sell it at Hogwarts to make some money, and Mum went mad at them. Told them they weren't allowed to make any more of it, and burned all the order forms†¦.She's furious at them anyway. They didn't get as many O.W.L.s as she expected.† O.W.L.s were Ordinary Wizarding Levels, the examinations Hogwarts students took at the age of fifteen. â€Å"And then there was this big row,† Ginny said, â€Å"because Mum wants them to go into the Ministry of Magic like Dad, and they told her all they want to do is open a joke shop.† Just then a door on the second landing opened, and a face poked out wearing horn-rimmed glasses and a very annoyed expression. â€Å"Hi, Percy,† said Harry. â€Å"Oh hello, Harry,† said Percy. â€Å"I was wondering who was making all the noise. I'm trying to work in here, you know I've got a report to finish for the office – and it's rather difficult to concentrate when people keep thundering up and down the stairs.† â€Å"We're not thundering, â€Å"said Ron irritably. â€Å"We're walking. Sorry if we've disturbed the top-secret workings of the Ministry of Magic.† â€Å"What are you working on?† said Harry. â€Å"A report for the Department of International Magical Cooperation,† said Percy smugly. â€Å"We're trying to standardize cauldron thickness. Some of these foreign imports are just a shade too thin – leakages have been increasing at a rate of almost three percent a year -â€Å" â€Å"That'll change the world, that report will,† said Ron. â€Å"Front page of the Daily Prophet, I expect, cauldron leaks.† Percy went slightly pink. â€Å"You might sneer, Ron,† he said heatedly, â€Å"but unless some sort of international law is imposed we might well find the market flooded with flimsy, shallow-bottomed products that seriously endanger -â€Å" â€Å"Yeah, yeah, all right,† said Ron, and he started off upstairs again. Percy slammed his bedroom door shut. As Harry, Hermione, and Ginny followed Ron up three more flights of stairs, shouts from the kitchen below echoed up to them. It sounded as though Mr. Weasley had told Mrs. Weasley about the toffees. The room at the top of the house where Ron slept looked much as it had the last time that Harry had come to stay: the same posters of Ron's favorite Quidditch team, the Chudley Cannons, were whirling and waving on the walls and sloping ceiling, and the fish tank on the windowsill, which had previously held frog spawn, now contained one extremely large frog. Ron's old rat, Scabbers, was here no more, but instead there was the tiny gray owl that had delivered Ron's letter to Harry in Privet Drive. It was hopping up and down in a small cage and twittering madly. â€Å"Shut up, Pig,† said Ron, edging his way between two of the four beds that had been squeezed into the room. â€Å"Fred and George are in here with us, because Bill and Charlie are in their room,† he told Harry. â€Å"Percy gets to keep his room all to himself because he's got to work.† â€Å"Er – why are you calling that owl Pig?† Harry asked Ron. â€Å"Because he's being stupid,† said Ginny, â€Å"Its proper name is Pigwidgeon.† â€Å"Yeah, and that's not a stupid name at all,† said Ron sarcastically. â€Å"Ginny named him,† he explained to Harry. â€Å"She reckons it's sweet. And I tried to change it, but it was too late, he won't answer to anything else. So now he's Pig. I've got to keep him up here because he annoys Errol and Hermes. He annoys me too, come to that. Pigwidgeon zoomed happily around his cage, hooting shrilly. Harry knew Ron too well to take him seriously. He had moaned continually about his old rat, Scabbers, but had been most upset when Hermione's cat, Crookshanks, appeared to have eaten him. â€Å"Where's Crookshanks?† Harry asked Hermione now. â€Å"Out in the garden, I expect,† she said. â€Å"He likes chasing gnomes. He's never seen any before.† â€Å"Percy's enjoying work, then?† said Harry, sitting down on one of the beds and watching the Chudley Cannons zooming in and out of the posters on the ceiling. â€Å"Enjoying it?† said Ron darkly. â€Å"I don't reckon he'd come home if Dad didn't make him. He's obsessed. Just don't get him onto the subject of his boss. According to Mr. Crouch†¦as I was saying to Mr. Crouch†¦ Mr. Crouch is of the opinion†¦Mr. Crouch was telling me†¦They'll be announcing their engagement any day now.† â€Å"Have you had a good summer, Harry?† said Hermione. â€Å"Did you get our food parcels and everything?† â€Å"Yeah, thanks a lot,† said Harry. â€Å"They saved my life, those cakes.† â€Å"And have you heard from -?† Ron began, but at a look from Hermione he fell silent. Harry knew Ron had been about to ask about Sirius. Ron and Hermione had been so deeply involved in helping Sirius escape from the Ministry of Magic that they were almost as concerned about Harry's godfather as he was. However, discussing him in front of Ginny was a bad idea. Nobody but themselves and Professor Dumbledore knew about how Sirius had escaped, or believed in his innocence. â€Å"I think they've stopped arguing,† said Hermione, to cover the awkward moment, because Ginny was looking curiously from Ron to Harry. â€Å"Shall we go down and help your mum with dinner?† â€Å"Yeah, all right,† said Ron. The four of them left Ron's room and went back downstairs to find Mrs. Weasley alone in the kitchen, looking extremely bad-tempered. â€Å"We're eating out in the garden,† she said when they came in. â€Å"There's just not room for eleven people in here. Could you take the plates outside, girls? Bill and Charlie are setting up the tables. Knives and forks, please, you two,† she said to Ron and Harry, pointing her wand a little more vigorously than she had intended at a pile of potatoes in the sink, which shot out of their skins so fast that they ricocheted off the walls and ceiling. â€Å"Oh for heaven's sake,† she snapped, now directing her wand at a dustpan, which hopped off the sideboard and started skating across the floor, scooping up the potatoes. â€Å"Those two!† she burst out savagely, now pulling pots and pans out of a cupboard, and Harry knew she meant Fred and George. I don't know what's going to happen to them, I really don't. No ambition, unless you count making as much trouble as they possibly can†¦.† Mrs. Weasley slammed a large copper saucepan down on the kitchen table and began to wave her wand around inside it. A creamy sauce poured from the wand tip as she stirred. â€Å"It's not as though they haven't got brains, she continued irritably, taking the saucepan over to the stove and lighting it with a further poke of her wand, â€Å"but they're wasting them, and unless they pull themselves together soon, they'll be in real trouble. I've had more owls from Hogwarts about them than the rest put together. If they carry on the way they're going, they'll end up in front of the Improper Use of Magic Office.† Mrs. Weasley jabbed her wand at the cutlery drawer, which shot open. Harry and Ron both jumped out of the way as several knives soared out of it, flew across the kitchen, and began chopping the potatoes, which had just been tipped back into the sink by the dustpan. â€Å"I don't know where we went wrong with them,† said Mrs. Weasley, putting down her wand and starting to pull out still more saucepans. â€Å"It's been the same for years, one thing after another, and they won't listen to – OH NOT AGAIN!† She had picked up her wand from the table, and it had emitted a loud squeak and turned into a giant rubber mouse. â€Å"One of their fake wands again!† she shouted. â€Å"How many times have I told them not to leave them lying around?† She grabbed her real wand and turned around to find that the sauce on the stove was smoking. â€Å"C'mon,† Ron said hurriedly to Harry, seizing a handful of cutlery from the open drawer, â€Å"let's go and help Bill and Charlie.† They left Mrs. Weasley and headed out the back door into the yard. They had only gone a few paces when Hermione's bandy-legged ginger cat, Crookshanks, came pelting out of the garden, bottle-brush tail held high in the air, chasing what looked like a muddy potato on legs. Harry recognized it instantly as a gnome. Barely ten inches high, its horny little feet pattered very fast as it sprinted across the yard and dived headlong into one of the Wellington boots that lay scattered around the door. Harry could hear the gnome giggling madly as Crookshanks inserted a paw into the boot, trying to reach it. Meanwhile, a very loud crashing noise was coming from the other side of the house. The source of the commotion was revealed as they entered the garden, and saw that Bill and Charlie both had their wands out, and were making two battered old tables fly high above the lawn, smashing into each other, each attempting to knock the other's out of the air. Fred and George were cheering, Ginny was laughing, and Hermione was hovering near the hedge, apparently tor n between amusement and anxiety. Bill's table caught Charlie's with a huge bang and knocked one of its legs off. There was a clatter from overhead, and they all looked up to see Percy's head poking out of a window on the second floor. â€Å"Will you keep it down?!† he bellowed. â€Å"Sorry, Perce,† said Bill, grinning. â€Å"How're the cauldron bottoms coming on?† â€Å"Very badly,† said Percy peevishly, and he slammed the window shut. Chuckling, Bill and Charlie directed the tables safely onto the grass, end to end, and then, with a flick of his wand, Bill reattached the table leg and conjured tablecloths from nowhere. By seven o'clock, the two tables were groaning under dishes and dishes of Mrs. Weasley's excellent cooking, and the nine Weasleys, Harry, and Hermione were settling themselves down to eat beneath a clear, deep-blue sky. To somebody who had been living on meals of increasingly stale cake all summer, this was paradise, and at first, Harry listened rather than talked as he helped himself to chicken and ham pie, boiled potatoes, and salad. At the far end of the table, Percy was telling his father all about his report on cauldron bottoms. â€Å"I've told Mr. Crouch that I'll have it ready by Tuesday,† Percy was saying pompously. â€Å"That's a bit sooner than he expected it, but I like to keep on top of things. I think he'll be grateful I've done it in good time, I mean, its extremely busy in our department just now, what with all the arrangements for the World Cup. We're just not getting the support we need from the Department of Magical Games and Sports. Ludo Bagman -â€Å" â€Å"I like Ludo,† said Mr. Weasley mildly. â€Å"He was the one who got us such good tickets for the Cup. I did him a bit of a favor: His brother, Otto, got into a spot of trouble – a lawnmower with unnatural powers – I smoothed the whole thing over.† â€Å"Oh Bagman's likable enough, of course,† said Percy dismissively, â€Å"but how he ever got to be Head of Department†¦when I compare him to Mr. Crouch! I can't see Mr. Crouch losing a member of our department and not trying to find out what's happened to them. You realize Bertha Jorkins has been missing for over a month now? Went on holiday to Albania and never came back?† â€Å"Yes, I was asking Ludo about that,† said Mr. Weasley, frowning. â€Å"He says Bertha's gotten lost plenty of times before now – though must say, if it was someone in my department, I'd be worried†¦.† â€Å"Oh Bertha's hopeless, all right,† said Percy. â€Å"I hear she's been shunted from department to department for years, much more trouble than she's worth†¦but all the same, Bagman ought to be trying to find her. Mr. Crouch has been taking a personal interest, she worked in our department at one time, you know, and I think Mr. Crouch was quite fond of her – but Bagman just keeps laughing and saying she probably misread the map and ended up in Australia instead of Albania. However† – Percy heaved an impressive sigh and took a deep swig of elderflower wine – â€Å"we've got quite enough on our plates at the Department of International Magical Cooperation without trying to find members of other departments too. As you know, we've got another big event to organize right after the World Cup.† Percy cleared his throat significantly and looked down toward the end of the table where Harry, Ron, and Hermione were sitting. â€Å"You know the one I'm talking about, Father.† He raised his voice slightly. â€Å"The top-secret one.† Ron rolled his eyes and muttered to Harry and Hermione, â€Å"He's been trying to get us to ask what that event is ever since he started work. Probably an exhibition of thick-bottomed cauldrons.† In the middle of the table, Mrs. Weasley was arguing with Bill about his earring, which seemed to be a recent acquisition. â€Å"†¦with a horrible great fang on it. Really, Bill, what do they say at the bank?† â€Å"Mum, no one at the bank gives a damn how I dress as long as I bring home plenty of treasure,† said Bill patiently. â€Å"And your hair's getting silly, dear,† said Mrs. Weasley, fingering her wand lovingly.† I wish you'd let me give it a trim†¦.† â€Å"I like it,† said Ginny, who was sitting beside Bill. â€Å"You're so old-fashioned, Mum. Anyway, it's nowhere near as long as Professor Dumbledore's†¦.† Next to Mrs. Weasley, Fred, George, and Charlie were all talking spiritedly about the World Cup. â€Å"It's got to be Ireland,† said Charlie thickly, through a mouthful of potato. â€Å"They flattened Peru in the semifinals.† â€Å"Bulgaria has got Viktor Krum, though,† said Fred. â€Å"Krum's one decent player, Ireland has got seven,† said Charlie shortly. â€Å"I wish England had got through. That was embarrassing, that was.† â€Å"What happened?† said Harry eagerly, regretting more than ever his isolation from the wizarding world when he was stuck on Privet Drive. â€Å"Went down to Transylvania, three hundred and ninety to ten,† said Charlie gloomily. â€Å"Shocking performance. And Wales lost to Uganda, and Scotland was slaughtered by Luxembourg.† Harry had been on the Gryffindor House Quidditch team ever since his first year at Hogwarts and owned one of the best racing brooms in the world, a Firebolt. Flying came more naturally to Harry than anything else in the magical world, and he played in the position of Seeker on the Gryffindor House team. Mr. Weasley conjured up candles to light the darkening garden before they had their homemade strawberry ice cream, and by the time they had finished, moths were fluttering low over the table, and the warm air was perfumed with the smells of grass and honeysuckle. Harry was feeling extremely well fed and at peace with the world as he watched several gnomes sprinting through the rosebushes, laughing madly and closely pursued by Crookshanks. Ron looked carefully up the table to check that the rest of the family were all busy talking, then he said very quietly to Harry, â€Å"So – have you heard from Sirius lately?† Hermione looked around, listening closely. â€Å"Yeah,† said Harry softly, â€Å"twice. He sounds okay. I wrote to him yesterday. He might write back while I'm here.† He suddenly remembered the reason he had written to Sirius, and for a moment was on the verge of telling Ron and Hermione about his scar hurting again, and about the dream that had awoken him†¦but he really didn't want to worry them just now, not when he himself was feeling so happy and peaceful. â€Å"Look at the time,† Mrs. Weasley said suddenly, checking her wristwatch. â€Å"You really should be in bed, the whole lot of you you'll be up at the crack of dawn to get to the Cup. Harry, if you leave your school list out, I'll get your things for you tomorrow in Diagon Alley. I'm getting everyone else's. There might not be time after the World Cup, the match went on for five days last time.† â€Å"Wow – hope it does this time!† said Harry enthusiastically. â€Å"Well, I certainly don't,† said Percy sanctimoniously. â€Å"I shudder to think what the state of my in-tray would be if I was away from work for five days.† â€Å"Yeah, someone might slip dragon dung in it again, eh, Perce?† said Fred. â€Å"That was a sample of fertilizer from Norway!† said Percy, going very red in the face. â€Å"It was nothing personal!† â€Å"It was,† Fred whispered to Harry as they got up from the table. â€Å"We sent it.†

Definition and Examples of Agreement in English Grammar

In grammar, agreement is the correspondence of a verb with its subject in person and number, and of a pronoun with its antecedent in person, number, and gender.  Another term for grammatical agreement is concord. Basic Principles In English, agreement is relatively limited. It occurs between the subject of a clause and a present tense verb, so that, for instance, with a third-person singular subject (e.g. John), the verb must have the -s suffix ending. That is, the verb agrees with its subject by having the appropriate ending. Thus, John drinks a lot is grammatical, but John drink a lot isnt grammatical as a sentence on its own, because the verb doesnt agree. Agreement also occurs in English between demonstratives and nouns. A demonstrative has to agree in number with its noun. So with a plural noun such as books, you have to use a plural these or those, giving these books or those books. With a singular noun, such as book, you use a singular this or that, giving this book or that book. This books or those book would be ungrammatical because the demonstrative doesnt agree with the noun.–Jame R. Hurford, Grammar: A Students Guide. Cambridge University Press, 1994 Keeping Track of Details Agreement is an important process in many languages, but in modern English it is superfluous, a remnant of a richer system that flourished in Old English. If it were to disappear entirely, we would not miss it, any more than we miss the similar -est suffix in Thou sayest. But psychologically speaking, this frill does not come cheap. Any speaker committed to using it has to keep track of four details in every sentence uttered: And all this work is needed just to use the suffix once one has learned it.–Steven Pinker, The Language Instinct. William Morrow, 1994 whether the subject is in the third person or not: He walks versus I walk.whether the subject is singular or plural: He walks versus They walk.whether the action is present tense or not: He walks versus He walked.whether the action is habitual or going on at the moment of speaking (its aspect): He walks to school versus He is walking to school. Tricky Nouns Some nouns are commonly used with singular verbs although plural in form: Some nouns are commonly plural in usage, even though naming something singular.–Patricia Osborn, How Grammar Works. John Wiley, 1989 news, politics, economics, athletics, molassesnouns that state a given time, weight, or amount of energytitles of books, newspapers, television shows, even of plural formHis trousers were old and torn.The suds are almost down the drain.Scissors are a great invention.The contents were ruined. Examples Many dogs are made anxious by loud noises.An anxious dog is not able to focus and maintain attention.Dogs and cats are the most common pets.A dog and a cat are in our house.Usually, either the dog or the cat is in my room.Abandoning a dog or a cat is grossly irresponsible. Examples and Observations Bill Bryson The manager was one of those people who are so permanently and comprehensively stressed that even their hair and clothes appear to be at their wits end.–The Life and Times of the Thunderbolt Kid. Broadway Books, 2006 James Van Fleet I have read statistics that show only five out of every 100 people become financially successful. By the retirement age of 65, only one of these people is truly wealthy.–Hidden Power. Prentice-Hall, 1987 Maxine Hong Kingston She brought back another woman, who wore a similar uniform except that it was pink trimmed in white. This womans hair was gathered up into a bunch of curls at the back of her head; some of the curls were fake.–The Woman Warrior: Memoirs of a Girlhood Among Ghosts. Alfred A. Knopf, 1976 Bell Hooks Feminist activists must emphasize the forms of power these women exercise and show ways they can be used for their benefit.–Feminist Theory: From Margin to Center, 2nd ed. Pluto Press, 2000 Agreement in Radio TR: I dont know. Understanding guys dont mean you should live with them. SS: Lester... TR: What? SS: Understanding guys doesnt mean you should live with them. TR: Thats what I said. SS: Lester, subjects, and verbs have to be in agreement. The subject of that sentence is not guys, its understanding, and understanding, which is a gerund, by the way, is singular and it takes a singular verb. TR: I got no idea what youre talking about.–Tom Keith and Sue Scott in English Majors. A Prairie Home Companion, May 18, 2002