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Make a quiz of ten questions including fill in the blanks for reported speech.
Quiz by Edel López López
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Make a quiz using this information: Professional Learning Communities Despite compelling evidence indicating that working collaboratively represents best practice, teachers in many schools continue to work in isolation. Even in schools that endorse the idea of collaboration, the staff's willingness to collaborate often stops at the classroom door. Educators must stop working in isolation and hoarding their ideas, materials, and strategies and begin to work together to meet the needs of all students. Educators who are building a professional learning community recognize that they must work together to achieve their collective purpose of learning for all. Therefore, they create structures to promote a collaborative culture. The powerful collaboration that characterizes professional learning communities is a systematic process in which teachers work together to analyze and improve their classroom practice. Teachers work in teams, engaging in an ongoing cycle of questions that promote deep team learning. This process, in turn, leads to higher levels of student achievement. Collaborative conversations call on team members to make public what has traditionally been privateâgoals, strategies, materials, pacing, questions, concerns, and results. These discussions give every teacher someone to turn to and talk to, and they are explicitly structured to improve the classroom practice of teachersâindividually and collectively.â Each team must have time to meet during the workday and throughout the school year. Teams must focus their efforts on crucial questions related to learning and generate products that reflect that focus, such as lists of essential outcomes, different kinds of assessment, analyses of student achievement, and strategies for improving results. Teams must develop norms or protocols to clarify expectations regarding roles, responsibilities, and relationships among team members. Teams must adopt student achievement goals linked with school and district goals. Professional learning communities judge their effectiveness on the basis of results. Working together to improve student achievement becomes the routine work of everyone in the school. Every teacher team participates in an ongoing process of identifying the current level of student achievement, establishing a goal to improve the current level, working together to achieve that goal, and providing periodic evidence of progress. Example of a PLC Goal: âWe will increase the percentage of students who meet the state standard in language arts from 83 percent to 90 percentâ or âWe will reduce the failure rate in our course by 50 percent.â The results-oriented professional learning community not only welcomes data but also turns data into useful and relevant information for staff.
Can you make me a 40 question quiz from the following information? he story of coffee has all the elements of a bestselling novel, such as chance happenings, luck, political intrigue, the high seas and great wealth. With research, you will find many stories and dates when this happened and dates when that happened. Often these stories and dates will conflict with each other. Whatever the history, coffee has become one of the most important trading commodities in the world. Being second only to oil and being one of the most popular beverages, behind tea, beer and of course, water. Coffee growing is a very labour-intensive operation and it provides important trading income for many nations and people throughout the world. The most famous story about the origin of coffee is the story of Kaldi a goat herder from Ethiopia. It is said he noticed that his goats became very active after eating the red berries of a certain plant. He tried a few himself and noticed the stimulating effect of the berries. It is then said that monks started drinking a beverage made from the berries to help stay awake for the prayers; this would have been around 1000 AD. Over the next few hundred years the Arab world started to use the berries as a beverage and coffee was born. In those early years, coffee was mostly confined to the Muslim world with the export of coffee plants and seeds banned. But coffee could not be hidden forever so eventually coffee was introduced to Constantinople and coffee houses were opened in 1475. European traders then brought coffee back to Europe by approximately 1600. At first, coffee was met with a hostile reaction, with some Christians calling it the âDevilâs Drinkâ and asking Pope Vincent III to ban the beverage. He tried coffee and liked it so much that he is claimed to have said âThis beverage is so delicious that it would be a sin to let only misbelievers drink it! Letâs defeat Satan by blessing this beverage, which contains nothing objectionable to a Christian!â Coffee shops sprung up in every city and became an important social and networking place to meet. This tradition continues today with the French word for coffee being âCafĂŠâ. Coffee is said to have changed the social fabric of society by providing a popular non-alcoholic alternative to beer and wine. For the first time in recorded history people were not drunk all the time. Coffee today is grown and enjoyed worldwide and is one of the few crops that small farmers in third-world countries can profitably export. The coffee plant is a tree that is pruned to grow to a height of approximately three metres. This makes cultivating the beans easier as most of the beans are handpicked. The plant has white flowers similar to jasmine that grow in clusters and set to become red cherry-like fruit; beneath the red skin are two pips which are the coffee beans. Because the berries ripen at varying times the fruit must be handpicked to select only those beans ripe for harvest. This requires the picker to pick from the same plant many times and is very labour intensive. This is why coffee is grown in developing countries where labour is cheaper and foreign income is needed. Coffee plants grow best in a mountain tropical climate between the Tropic of Capricorn and the Tropic of Cancer. This mountainous land is another reason why machine picking is very difficult and hand picking is preferred. There are two main species of coffee grown today: Coffee Arabica. Coffee Robusta. Robusta grows at lower altitudes and produces a larger crop than Arabica; therefore, it is cheaper to produce Arabica is the most popular and generally considered to give superior flavour. Most Robusta is grown in Asia and Africa. About 75% of coffee grown is Arabica and 25% Robusta. Robusta is more often used as a blend with Arabica rather than a standalone coffee; used as a filler coffee in the production of instant or to add extra caffeine to an Arabica coffee for the European markets. Robusta is higher in caffeine than Arabica, but the flavour is not as palatable as the more popular Arabica bean. Coffee is produced in about 60 countries throughout the world but production is dominated by three countries producing approximately half the crop: Brazil, Vietnam and Colombia.
Use this to make a quiz: Excellent! Using an online game is a fantastic way to boost engagement. Here is a list of scenarios you can use. I've designed them to be clear and concise for a game format. I've also added a few "challenge" scenarios at the end that could fit more than one theory to really get your students thinking critically. You can copy and paste these right into platforms like Kahoot!, Blooket, or Gimkit. --- ### **Scenarios for Your Online Game** **Instructions for Students:** Read the scenario and choose the theory that BEST explains why the crime was committed. 1. **Scenario:** An accountant has been secretly stealing small amounts of money from his clients' accounts for years. He has a system that he believes is foolproof, and he has calculated that the potential reward is worth the small risk of being caught. * **Best Fit:** Choice Theory 2. **Scenario:** A high school student who lives in a neighborhood with high unemployment and rundown buildings begins to vandalize property with a group of friends who feel ignored by the city. * **Best Fit:** Social Disorganization Theory 3. **Scenario:** A young woman desperately wants the new smartphone and designer clothes she sees all over social media, but she has no way to afford them. She decides to start stealing packages from front porches to get what she wants. * **Best Fit:** Strain Theory 4. **Scenario:** A man is arrested for assault after getting into a fight at a restaurant. His family tells the police that he has always had a "short fuse" and has struggled with anger and aggression since he was a child, a trait that his father also had. * **Best Fit:** Biological/Psychological Theory 5. **Scenario:** The youngest child in a family of well-known burglars is caught breaking into a house. When questioned, he says he learned everything he knows from watching and helping his older siblings. * **Best Fit:** Learning Theory 6. **Scenario:** A corporate executive is caught illegally dumping toxic waste to save his company money. He decided that the cost of proper disposal was too high and the chance of being caught was low. * **Best Fit:** Choice Theory 7. **Scenario:** After her parents' messy divorce, a teenager starts skipping school and shoplifting. A counselor suggests her actions stem from untreated anxiety and depression. * **Best Fit:** Biological/Psychological Theory 8. **Scenario:** In a community where the local factory closed down and police presence is low, a group of residents forms a vigilante group to "patrol" the streets, often resorting to violence and intimidation. * **Best Fit:** Social Disorganization Theory --- ### **Challenge Scenarios (Could fit multiple theories)** 9. **Scenario:** A college student starts selling forged concert tickets to pay for their tuition. They learned how to make the fake tickets from a video online and felt it was the only way to stay in school. * **Possible Answers:** Strain Theory (can't afford tuition), Learning Theory (learned online), Choice Theory (weighed the risks). 10. **Scenario:** A person living on the streets with no job prospects is arrested for stealing a warm coat from a department store during a blizzard. * **Possible Answers:** Strain Theory (no means to achieve the goal of being warm), Choice Theory (made a rational decision to steal to survive). These scenarios should give you great content for your game. Have fun with it, and let me know if you need any more!
Make a multiple choice quiz for my year 8 science students based on the science in this transcript from a video: 3°C 0:04 It can be the difference between snow and sleet 0:08 Wearing a jacket or not 0:11 In your day-to-day life, it may not seem significant 0:15 But 3°C of global warming would be catastrophic 0:20 Heatwaves, droughts, extreme precipitation, even fire 0:25 3°C of warming is really disastrous 0:28 The scary thing is, the world is well on its way there 0:32 Since the industrial revolution, the Earth has warmed between 1.1°C and 1.3°C 0:40 This is a problem that babies you pass in the street will have to live with 0:46 Children born today... 0:47 ...are up to seven times more likely to face extreme weather than their grandparents 0:52 If global temperatures do rise by 3°C... 0:55 ...what would their world look like? Climate change is already having devastating effects 1:03 Rising sea levels 1:05 Desertification 1:07 Hollywood has always enjoyed imagining the end of the world 1:11 While blockbusters like this are clearly fiction... 1:14 ...this film will show the scenario we all face... 1:17 ...unless more drastic measures are taken to stop burning fossil fuels 1:30 In some parts of the world the effects of inaction are already clear 1:35 The slums of Bangladeshâs capital are filling up with climate migrants 1:41 Minara comes from Bhola District, an area in southern Bangladesh 1:46 There, like many other parts of the country... 1:49 ...rivers swollen by heavier rain and melting Himalayan glaciers... 1:53 ...are washing away peopleâs homes 1:56 Many, like her, have lost everything 2:00 Our home in Bhola had endless amounts of land 2:03 There was lots of space for farming, we had a spacious house 2:08 There were different types of fruits, vegetation and trees growing at home 2:12 We used to eat the fruit from our own trees 2:18 I canât eat them now because they don't exist anymore 2:21 Since the river flooded for the third time, I had to flee to Dhaka 2:26 Life was much better back home 2:29 It was unbearable to live through, truly intolerable 2:33 We didnât have the time to save anything at all 2:38 1.1°C to 1.3°C of global warming has already transformed Minaraâs life 2:45 Itâs one of the reasons why so many migrants like her... 2:47 ...are moving to the city each year... 2:50 ...nearly 400,000 according to the last estimate 2:53 And climate models show there could be much worse to come How climate modelling works 3:02 Climate scientist Joeri Rogelj... 3:04 ...has spent the last ten years modelling future climate scenarios... 3:08 ...for the United Nations 3:10 The models we use to carry out this exercise... 3:13 ...really represent the state of the art... 3:15 ...of our current knowledge of climate change and where we are heading 3:19 Joeriâs projections use data collected by hundreds of scientists around the world 3:26 Here this is the 3°C level... 3:28 ...and so there is at least a one-in-four chance that under current policies... 3:32 ...we would hit 3°C by the end of the century 3:36 This is just one of the scenarios Joeri looks at 3:40 Another one imagines that all policy promises are kept 3:44 The most optimistic assumes that all promises have been kept... 3:47 ...and net-zero targets are met 3:50 Where our best estimate ends up around 2°C at the end of the century... 3:54 ...there is still a one-in-20 chance that we end up with 3°C instead 3:59 One would not be entering a plane if there is a one-in-20 chance... 4:03 ...that the plane will crash Nowhere is safe from global warming 4:07 A rise of 3°C would affect everyone 4:10 Even wealthy cities in rich countries wouldnât be immune to the consequences 4:15 European capitals like Paris and Berlin... 4:18 ...would bake under more extreme heatwaves 4:22 Frequent storm-surges in New York could turn parts of the city desolate 4:27 In many ways, cities magnify, intensify climate events 4:33 Cities are hotter than the places around them... 4:36 ...they tend to be more vulnerable to flooding 4:39 And you can get a really bad event in a city in a way that you canât in the countryside 4:46 And because of their denser populations... 4:49 ...disasters in a city affect far more people 4:52 Some cities might be badly prepared for the changes coming 4:56 But they have the means to adapt 4:59 Cities tend to be wealthier than surrounding places 5:03 They have a lot of amenities 5:05 A city that has taken seriously the risks of a 3°C world... 5:08 âŚwouldnât necessarily be a worse place to be in a 3°C world 5:12 But a city that hasnât prepared for these sort of eventualities... 5:16 ...that might be a really nasty place The impact of prolonged droughts 5:20 So far, many developed cities have got off lightly... 5:24 ...but some rural parts of the world are suffering disproportionately 5:29 Smallholdersâsmall-scale farmersâare particularly vulnerable to climate change 5:35 And there are over 600 million around the world 5:38 Smallholders with farms under two hectares... 5:40 ...produce around a third of the global food supply 5:46 Central Americaâs âDry Corridorâ... 5:48 ...supports a mix of smallholdings and medium-sized farms 5:53 Sandwiched between the Pacific Ocean and the Caribbean Sea... 5:56 ...the area is prone to droughts 6:08 Israel RamĂrez Rivera is a smallholder in Guatemala 6:12 Here, climate change is making the dry seasons longer, and more severe 6:18 This is the biggest ear of maize that this plot could deliver 6:23 He depends on his crops of corn and beans 6:26 But theyâre getting harder to grow 6:30 The surrounding mountains... 6:32 ...used to provide us with native food... 6:38 ...and now that isnât an option anymore... 6:41 ...due to climate change and its effects 6:46 Nearly two-thirds of the smallholders in the Dry Corridor now live in poverty 6:52 The impact of all of this for us... 6:59 ...malnutrition among children 7:03 Weâve lost a few 7:07 For my crops especially, the midsummer heat is harder than before 7:16 The plant dries up and canât provide us... 7:19 ...with the necessary food provision 7:24 Severe droughts in Central America... 7:26 ...are now four times more likely than they were last century 7:30 Many families from here have gone to the States 7:37 The economic despair and debts... 7:44 ...have pushed many people from this community to do this journey 7:53 Migration from Guatemala to the United States has quadrupled since 1990 7:59 Not all of this has been due to climate change 8:02 But longer droughts would force even more to move 8:05 In a 3°C world, annual rainfall in this region... 8:09 ...could drop by up to 14% 8:12 At 3°C, over a quarter of the worldâs population... 8:16 ...could endure extreme droughts for at least a month of the year 8:19 Northern Africa could see droughts that last for years at a time Rising sea levels, storm surges and flooding 8:24 But for some, too much water will be the problem 8:29 10% of the worldâs population lives on a coastline... 8:32 ...thatâs less than 10 metres above sea level 8:35 For these coastal inhabitants, a 3°C world would spell disaster 8:40 By 2100, global sea levels could have climbed by half a metre from 2005 levels 8:46 Low-lying cities like Lagos would be especially vulnerable... 8:49 ...with up to up to a third of the population displaced 8:54 And in Fiji, rising waters are already upending lives 9:04 You can see the graveyard there, itâs all under water now... 9:08 ...due to this rising sea level and climate change 9:15 The village of Togoru in Fiji is being swallowed by the sea 9:19 Barney Dunn, the village headman, has seen over half the village disappear 9:24 Relativesâ houses have been abandoned, and family graves are now under water 9:29 We have been asked by the government to relocate... 9:32 ...but no one wants to relocate... 9:34 ...because we have our great-great-grandparents down there in the sea 9:39 This is the place weâve been brought up in 9:41 ...itâs not easy to leave 9:44 Past attempts to build a seawall havenât worked 9:48 But Barney sees building a new one as the villageâs only hope 9:52 If they do that, maybe we can save whatever is left 9:56 But if we donât have the seawall, then it will be keep eroding and time will come... 10:01 ...maybe in ten,15 years, Togoru will be all eroded 10:05 Rising seas also mean storms cause more floods 10:11 And many more countries could suffer 10:14 The Philippines and Myanmar are just two countries... 10:17 ...that will also see an increase in storm surges in a 3°C world 10:21 To escape, many will move⌠10:24 âŚoften, to urban areas Extreme heat and wet-bulb temperatures 10:27 Half the worldâs population already lives in cities... 10:31 ...almost a third in slums 10:36 For them, a 3°C world could be deadly 10:40 Minara has moved to Dhaka to escape the impact of climate change 10:44 But life could get even worse for her 10:47 Iâm struggling a lot nowadays 10:49 The heat during the day is unbearable 10:52 Even late at night it doesnât cool down 10:57 The heat is getting more intense every day 10:59 I mean, itâs going to get much worse 11:03 I can barely survive it now, how will I live through it in the future? 11:08 Dhaka is getting hotter 11:11 In the last 20 years the average daytime temperature... 11:13 ...has crept up by nearly half a degree 11:17 Days that approach 40°C are now being reported 11:20 And high so-called wet-bulb temperatures are on the rise 11:26 A wet-bulb temperature is a measure of heat and humidity 11:30 Humans cool themselves by sweating⌠11:32 But in these conditions, when relative humidity is near 100%... 11:36 ...sweat doesnât evaporate well 11:38 So people canât cool down⌠11:41 ...even if given unlimited shade and water 11:45 At a high wet-bulb temperature, the body canât lose heat... 11:49 ...and so it gets hotter and hotter... 11:51 ...and the body is designed to work at a given temperature 11:53 And if it gets too hot inside, you will die 11:58 The human limit for wet-bulb temperatures is 35°C... 12:02 ...around skin temperature 12:04 Dhaka will have a much higher chance... 12:05 ...of reaching dangerous wet-bulb temperatures... 12:07 ...if global warming reaches 3°C 12:12 You canât really adapt to that 12:14 You have to get out. If the temperature is so high that you canât work... 12:20 ...canât do hard manual labour outside for significant parts of the year... 12:25 ...then many places will become functionally no longer part of the economy 12:33 Jacobabad in Pakistan, and Ras al Khaimah, in the United Arab Emirates... 12:37 ...have already recorded deadly wet-bulb temperatures 12:40 More of the tropics and the Persian Gulf... 12:43 ...as well as parts of Mexico and the south-eastern United States... 12:47 ...could all get to this threshold by the end of the century 12:50 Climate modelling might show us the weather Increased migration and conflict 12:52 But it doesnât show us its other effects on society 12:56 Established migration patterns could change 12:59 Climate disasters may exacerbate reasons people cross borders 13:03 Within countries, more people will move to cities 13:07 In a 3°C world, tens of millions of people a year... 13:10 ...could be displaced by disasters made worse by climate change 13:15 When people are displaced by climate... 13:18 âŚthey may well go to cities... 13:19 ...because cities are the places that attract people from the countryside already 13:25 A lot of people who can get to the developed world... 13:28 ...not least because the developed world tends to be less hot, will give that a go 13:35 As migration around the world increases... 13:38 ...there could be more competition for fewer resources 13:42 Waterâalready a highly contested resourceâwill be a focal point 13:47 Turkeyâs new Ilisu dam has reduced the flow of water into Iraq 13:53 China lays claim to rivers vital to India and Pakistan 13:57 The prospect of a water-conflict makes people very uneasy 14:03 How national tensions would exacerbate those sorts of reactions... 14:08 ...in a 3°C world... 14:09 ...is the sort of thing that no one should really want to find out 14:14 I think youâd have to be incredibly sanguine... 14:16 ...not to think that the sort of climate extremes that we talk about... 14:19 ...in a 3°C world wouldnât lead some places... 14:22 ...to the brink of societal collapse 14:25 Those lucky enough to escape unrest... Adaptation and mitigation are crucial 14:28 ...would still have to adapt to a radically different world 14:32 People can adapt to climate change in all sorts of ways, one of the most obvious ones... 14:37 ...is air conditioning 14:39 But other ways to adapt at a local or regional level... 14:42 ...I mean, one of the most obvious is diversifying agriculture 14:47 There are physical things you can do, like seawalls 14:52 The fact that people can adapt and that adaptation will reduce suffering... 14:57 ...doesnât mean that it will eliminate suffering 15:00 Suffering is built into this whole process of heating up the planet 15:06 Adaptation will only get the world so far 15:09 The best way to deal with a 3°C world... 15:12 ...is not to go to a 3°C world 15:14 And thatâs why increasing efforts on mitigation are important 15:17 Itâs why working towards negative emissions... 15:20 ...that could bring down the temperature after it peaks are important 15:25 Once you get to a 3°C world, you are in real bad global trouble 15:33 The scale of change needed... 15:35 ...and the slow progress of governments so far... 15:38 ...means 3°C of warming is uncomfortably likely unless more is done 15:44 Despite existing pledges, greenhouse-gas emissions... 15:48 ...are still set to rise by 16% from 2010 levels by 2030 15:54 The need to act has never been clearer 15:57 Thereâs still time to reduce emissions, so that a 3°C world remains fiction... 16:02 ...rather than becoming fact
Sure! Here's a solid list of **AP English Literature vocabulary**âterms that often come up in class, essays, and the AP exam. I'll break it down into categories to make it easier to study. --- ### đ **Literary Devices & Techniques** 1. **Alliteration** â Repetition of initial consonant sounds 2. **Allusion** â A reference to another text, event, or figure 3. **Anaphora** â Repetition of a word or phrase at the beginning of successive clauses 4. **Antithesis** â Contrast of ideas in a balanced or parallel construction 5. **Apostrophe** â Addressing someone absent, dead, or nonhuman as if present and able to respond 6. **Assonance** â Repetition of vowel sounds within nearby words 7. **Asyndeton** â Omission of conjunctions between parts of a sentence 8. **Consonance** â Repetition of consonant sounds, often at the end of words 9. **Diction** â Word choice (formal, informal, colloquial, etc.) 10. **Enjambment** â Continuation of a sentence without pause beyond the end of a line in poetry --- ### đ§ **Figurative Language** 1. **Hyperbole** â Extreme exaggeration 2. **Imagery** â Descriptive language that appeals to the senses 3. **Irony** - *Verbal*: Saying the opposite of whatâs meant - *Situational*: When the outcome is the opposite of what's expected - *Dramatic*: Audience knows something characters donât 4. **Metaphor** â A direct comparison without using "like" or "as" 5. **Metonymy** â Substituting the name of one thing with something closely related (e.g. "The crown" for royalty) 6. **Synecdoche** â A part representing the whole (e.g. "All hands on deck") 7. **Personification** â Giving human traits to nonhuman things 8. **Simile** â A comparison using "like" or "as" 9. **Symbol** â An object, character, or color that represents something beyond itself --- ### âď¸ **Poetic & Rhetorical Terms** 1. **Caesura** â A pause in a line of poetry, often marked by punctuation 2. **Couplet** â Two lines of poetry that usually rhyme 3. **Iambic Pentameter** â A line with five iambs (unstressed-stressed syllables) 4. **Blank Verse** â Unrhymed iambic pentameter 5. **Free Verse** â Poetry with no fixed meter or rhyme 6. **Elegy** â A mournful poem, often for the dead 7. **Ode** â A lyric poem expressing emotion, often in honor of something 8. **Sonnet** â A 14-line poem with a specific rhyme scheme (Shakespearean or Petrarchan) --- ### đ **Narrative & Structure Terms** 1. **Tone** â The author's attitude toward the subject 2. **Mood** â The feeling or atmosphere the reader experiences 3. **Theme** â The central idea or message in a work 4. **Motif** â A recurring element that has symbolic significance 5. **Foil** â A character who contrasts with another character to highlight traits 6. **Foreshadowing** â Clues or hints about what will happen later 7. **Juxtaposition** â Placing two elements side by side to present a contrast 8. **Point of View** â Perspective from which the story is told (1st, 2nd, 3rd person) 9. **Stream of Consciousness** â Narrative style that mimics thoughts and feelings 10. **Frame Narrative** â A story within a story --- Want me to make flashcards, a quiz, or a PDF study guide with these? Or need help using them in a literary analysis essay?
The Pedestrian (adapted) by Ray Bradbury Mr. Leonard Mead loved to walk outside at night. The city was quiet at eight oâclock on a misty November evening. He liked to put his hands in his pockets and stroll along the cracked sidewalks, stepping over grass that grew between the concrete. He would stop at the corners, look down the empty streets, and choose which way to go. It didnât really matter which way he picked, because he was always alone in the year 2053. Sometimes, Mr. Mead would walk for hours and miles, coming home only at midnight. As he walked, he saw houses with their windows dark, like he was walking through a graveyard. Sometimes, he saw tiny flashes of light from behind curtains or heard soft voices from open windows. Mr. Mead wore sneakers so his footsteps wouldnât make noise. If he wore shoes with hard heels, the dogs would bark and people might look out their windows. He liked being quiet and unnoticed as he walked in the cool November air. On this night, Mr. Mead walked west, toward the sea. The air was cold and frosty, making his nose sting and his lungs feel fresh. He listened to the sound of his shoes in the fallen leaves and sometimes picked up a leaf to look at it under the streetlights. As he walked, he whispered to the houses, âHello in there. Whatâs on TV tonight? Where are the cowboys? Is the cavalry coming?â But the street was silent and empty, with only his shadow moving. He checked his watch. âEight-thirty. Is it time for a quiz show? Or a funny show?â He thought he heard laughter from a house, but nothing else happened. He kept walking, sometimes stumbling over the broken sidewalk. In all his years of walking, he had never seen another person out at night. He reached a big intersection where two highways crossed. During the day, it was full of cars, but now it was empty and quiet, like a dry riverbed. Mr. Mead turned onto a side street, heading home. Suddenly, a police car turned the corner and shined a bright light on him. He stood still, surprised by the light. A metallic voice from the car said, âStand still. Donât move! Put up your hands!â Mr. Mead obeyed. The police car asked, âWhatâs your name?â âLeonard Mead,â he answered. âWhatâs your job?â âI guess Iâm a writer,â Mr. Mead said. The police car replied, âNo profession.â Mr. Mead hadnât written anything in years, since people didnât buy books or magazines anymore. People just stayed inside their houses, watching TV. The car asked, âWhat are you doing out?â âIâm walking,â Mr. Mead said. âWalking? Just walking?â the car repeated. âYes,â he said. âWhere are you walking? Why?â âFor air. To see things,â Mr. Mead answered. âYour address?â âEleven South Saint James Street.â âDo you have air in your house? An air conditioner?â âYes.â âDo you have a TV?â âNo.â âNo?â The car was quiet for a moment. âAre you married?â âNo,â Mr. Mead said. âNot married,â the car said. The night was cold and quiet. âJust walking, Mr. Mead?â âYes.â âBut why?â âI told you. For air, to see, and just to walk.â âDo you do this often?â âEvery night for years.â The police car was silent for a moment. Then it said, âGet in.â The back door opened. âWait, I havenât done anything!â Mr. Mead protested. âGet in,â the car repeated. Mr. Mead looked into the car. There was no one inside, just an empty front seat. The back seat was like a small jail cell, cold and hard. âWhere are you taking me?â he asked. The car answered, âTo the Psychiatric Center for Research on Regressive Tendencies.â Mr. Mead got in. The door closed, and the car drove away through the empty streets. As they passed his house, he saw that all the lights were on. âThatâs my house,â he said, but no one answered. The car drove off into the night, leaving the streets empty and silent for the rest of the cold November night.
Make mcq quiz with 4 option in which one is correct -'10 Basis of Material Science ⢠.....;;;";;;"~~;;,,;;,,,,;.;.,,;;,,,;,,;.;,.,------------ 6. Temporary materials: Some materials are meant to be placed in the oral cavity for a short period of time for different reasons. ⢠Temporary crowns: While a permanent crown is prepared in the dental laboratory, the patient must wait for few days before it can be fabricated and cemented into place. Does patient experience any problems during this time period? If the tooth is vital (the pulp is alive), the patient is likely to experience pain and sensitivity while eating and drinking, also it looks unesthetic. What can be done to solve this problem? A temporary crown is placed before the patient leaves the clinic. It is constructed and luted in the same appointment in which the crown preparation is done. Temporary crowns are not very strong or esthetic but they serve adequately till the permanent crown is ready to be cemented. ⢠Temporary restorations: Sometimes it is difficult to decide immediately the best line of treatment for a particular tooth. The exact condition of the pulp may not be obvious to the dentist from the patient's symptoms. A dentist removes all or part of the decay and then places a temporary restoration to have time to observe the behaviour of the pulp or to give the pilip time to heal before deciding the further treatment required. Classification based on Location of Fabrication 4,9 Materials can be classified based on the location of fabrication into: ⢠Direct restorative materials. ⢠Indirect restorative materials Direct restorative materials: They include those materials which are used to restore cavity preparations directly in the oral cavity (Box 1.5). Box 1.5: Examples of direct restorative materials Amalgam, composites, glass ionomer and other materials, which set by chemical reactions in the mouth. Indirect restorative materials: It includes those restorations which must be fabricated outside the mouth, indirectly on a cast/ model/ die, because their processing condition would harm oral tissues. Materials used in the construction of such prosthesis are called indirect restorative materials (Box 1.6). Box 1.6: Examples of indirect restorative materials Gold inlays, crowns of metal, ceramic and polymers, which are processed at elevated temperatures. Some indirect composite restorations can be processed under specific wavelength of light, e.g. Ceramage. Classification based on Longevity of Use 1. Permanent restorations: These restorations are not planned to be replaced for a particular time period. Though they are referred to as permanent, actually they are not, e.g. fillings, crowns, bridges and dentures do not last forever (Fig. 1.5). 2. Temporary restorations: These restorations are planned to be replaced in a short period of time, such as few days to weeks. For ~ Permanent C/) c c -.2 0 c- :;::; Cll co Interim ~ Q; 0 .8ll::1iJ C/) o~ Cll a:: c:=:J Temporary Time period Fig. 1.5: Diagram depicting the time period of use of a restoration. (Arrow in permanent restoration depicts that such restorations are not planned to be replaced for a long period of time.) Introducton to Dental Materials Dental materials Box 1.7: Characteristics of metals 1. High thermal and electrical conductivity 2. Ductility (pure metals are very soft and they can be bent without breaking) 3. Opacity (they do not transmit light) 4. Luster (they have a surface that strongly reflects light and appears bright and shiny) 5. They tend to dissolve to some extent in water or other aqueous solutions, producing cations. 6. All metals are white (actually gray) except for gold, which is yellow, and copper, which is reddish. 7. All metals are solid at room temperature except mercury, which is liquid at room temperature and is used with silver alloys as amalgam. 8. All metals have high melting temperatures because of high strength of the metallic bond that holds the atoms together. 3. Polymers 4. Composites Composites are mixtures of two or more of the first three classes in which the different components remain distinct from one another in the final structure. A common example is composite resin. Fig. 1.7a: Three-dimensional structure of iron (metal) Metals Metals are the oldest of the three classes of materials that have been used as dental materials. Metals are characterized by metallic bonds (Box 1.7) which will be discussed in the next chapter. Metals solidify with their atoms in a regular or crystalline arrangement (see Chapter 2), often in the form of a cube (Fig. 1.7a). example, temporary fillings done in a tooth during root canal treatment, which have to be replaced within 2-4 days during subsequent visits. They are used to protect the tooth and provide function till the final restoration is done. 3. Interim restoration: At times, dental treatment requires "long-term" definite temporary restorations or "interim" restorations. For examle, a 7-year-old child, met with trauma and fractured one of his central incisors. A large composite build- up may serve his immediate requirement until the root formation is completed and a permanent crown is placed. 5 Classification based on the Chemical Nature of the Material These are the atoms that make up a material and the way they are bonded together determine the properties of that materiaLS Weak bonds make for weak materials and vice versa (Table 1.4). Materials can be classified into different categories based on their primary atomic bonds (Fig. 1.6): 1. Metals 2. Ceramics Fig. 1.6: Classification of dental materials based on chemical nature 12 Basis of Material Science Box 1.9: Benefits of ceramics in dentistry 1. Many ceramic oxides are used as pigmenting agents. These oxides produce good range of colors. Due to this characteristic, we are able to match almost any tooth color with good esthetic results. 2. They are inert, i.e. not chemically reactive. This quality provides ceramics with good bio- compatibility. 3. Ceramic materials are translucent, like natural teeth. This translucency gives the ceramic crown a more natural appearance than any other dental material. Fig. 1.7b: Internal arrangement of tetrahedral structure of ceramic (silica) four large oxygen atoms surround smaller silicon atom Ceramics A ceramic is a compound formed by the union of a metallic and a non-metallic element (Box 1.8). Most of these materials are oxides, formed by the union of oxygen with metals such as silicon, aluminum, calcium and magnesium (Fig.1.7b). Ceramics may be simple or complex. Examples of simple ceramics are alumina and silica. Examples of complex ceramics are feldspar (potassium aluminum silicate) and kaolin (hydrated aluminum silicate). Ceramics may be crystalline or non- crystalline (i.e. amorphous). Porcelain is a specific type of ceramic used extensively in dentistry (Box 1.9). Box 1.8: Characteristics of ceramics 1. High melting points. 2. Brittleness, which means they cannot be bent or deformed (no sliding) to any extent without actually cracking and breaking. 3. They are poor conductor of heat and electricity. 4. They are chemically inert. 5. They have excellent esthetic result in terms of matching natural teeth. Fig. 1.8: Stucture of synthetic polymer Polymers They are the latest addition (early to mid- 1900s) to dental materials. Most of the polymers are nowadays synthesized by humans. Polymers are giant, long-chain organic molecules (Fig. 1.8). Polymers are characterized by covalent bonds within each molecule, giving them tremendous strength in a single direction. Try to break a nylon rope by pulling it! They are poor conductors of heat and electri- city. Most polymers have a structure containing thousands of carbon atoms linked together like beads on a string. Others, such as silicone polymers are formed with silicon-oxygen bonds. Introducton to Dental Materials Table 1.4: Characteristics of different materials 13 Characteristics Bond Properties Crystal structure Metals Metallic bonding High strength and hardness, high electrical and thermal conductivity BCC, FCC, or HCP unit cells Ceramics Ionic or covalent bonding, or both High hardness and stiffness, electrically insulating, refractory, and chemically inert Crystalline or amorphous Polymers Covalent bonding Low sensitivity, high electrical resistivity, and low thermal conductivity, strength and stiffness vary widely Amorphous and crystalline Composites Composites are combinations of any of the basic ceramic, metallic and polymeric materials (Box 1.10). Each material that makes up composites is called a phase. Their properties tend to be somewhere between those of their basic constituents and are used to enhance their performance, longevity and handling chracterstics. Box 1.10: Types of composites in dentistry 1. Ceramic - metallic composite: Tungsten carbide bur. 2. Metal - polymer composite: Die materials in dental laboratory. 3. Ceramic - polymer composite: Enamel, dentin, bone and restorative composites. A composite is a kind of "combination" of materials, which compliment each other. The properties lacking in one material are compensated by those of the other material. For example, restorative composite has two phases, namely resin and fillers. Teeth and bones are examples of natural composites. Enamel is a composite of hydroxyapatite (which is a ceramic material) and protein (which is a polymer). EVALUATION OF DENTAL MATERIALS Most manufacturers of dental materials maintain a quality assurance programme (As per international standard like ADA specifications) and materials are thoroughly tested before being released into the market for dental practitioner (Fig. 1.9). Laboratory Evaluations Most ADA/ ANSI specifications involve laboratory tests. The tests performed as per these specifications are useful but they all are performed in vitro, (carried out in the laboratory away from the clinical conditions) which have a lot of limitations in clinical practice.lO Clinical Notes 1. For example, most of the direct restorative materials are tested for their compressive strength but ultimately the material is subjected to a combination of compressive, tensile and shear stresses, which may decide the final success or failure of the material under masticatory load. 2. Similarly upper dentures mostly fracture along the midline because of bending. Hence a bending or transverse strength ~B-a-s-is-o-f-M-a-t-e-ria-I-S~c-ie-n-c-e-------------- ---------. test is far more meaningful for denture base materials than a compression test. Clinical Trials The majority of new materials are subjected to extensive clinical trials normally in co-operation with a dental college or hospital departments prior to their release. CONCLUSION As the number of available materials is going up, it is important that the dentist remains more aware about new products so that their judgement about the selection of material remains successful. Materials which have not been thoroughly evaluated should be avoided, specially with clinical dentistry falling under Consumer Protection Act (CPA). I Research and development I iI Manufacturer/analysis Ideal requirements for clinical use: Thermal, optical, mechanical, chemical, biological Available materials and their properties are evaluated Launch of new I product Choice and selection of material by the dentist Critical assessment based on clinical performance I I H feedback to I
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