Friday, March 20, 2020

The Rather Interesting History of Speak and Spell

The Rather Interesting History of Speak and Spell The Speak and Spell is a handheld electronic device and educational toy with a very interesting place in history. The toy/learning aid was developed in the late 1970s by Texas Instruments and introduced to the public at the Summer Consumer Electronics Show in June 1978. Its claim to fame is that the Speak and Spell was the first commercial product to use a brand new technology, called DSP technology. According to the IEEE: the Speak and Spell digital signal processing (DSP) innovation in audio processing is the starting milestone for the huge digital signal processing industry that has a more than $20 Billion market today. Using digital signal processing has grown tremendously with the development of analog to digital and digital to analog conversion chips and techniques. Digital signal processors are used in many of the consumer, industrial, and military applications. Digital Signal Processing By definition, DSP (short for digital signal processing) is the manipulation of analog information into digital. In Speak and Spells case, it was analog sound information that was converted into a digital form. The Speak and Spell was a product that was the result of Texas Instruments research into the area of synthetic speech. By being able to speak to children, the Speak and Spell was able to teach both the correct spelling and pronunciation of a word. Research and Development of the Speak and Spell The Speak and Spell marked the first time the human vocal tract had been electronically duplicated on a single chip of silicon. According to the manufacturers of the Speak and Spell, Texas Instruments, research on the Speak and Spell began in 1976 as a three-month feasibility study with a $25,000 budget. Four men worked on the project in its early stages: Paul Breedlove, Richard Wiggins, Larry Brantingham, and Gene Frantz. The idea for the Speak and Spell originated with engineer Paul Breedlove. Breedlove had been thinking about potential products that could use the capabilities of the new bubble memory (another Texas Instrument research project) when he came up with the idea for the Speak and Spell, originally named The Spelling Bee. With technology being what it was at that time period, speech data required a challenging amount of memory, and Texas Instruments agreed with Breedlove that something like the Speak and Spell could be a good application to develop. In an interview conducted by Benj Edwards of Vintage Computing with one of the Speak and Spell team members, Richard Wiggins, Wiggins reveals the basic roles of each of the team in the following way: Paul Breedlove originated the idea of a learning aid for spelling.Gene Frantz was responsible for the overall product design: spelling words, case design, display, and operation.Larry Brantingham was the integrated circuit designer.Richard Wiggins wrote the voice processing algorithms. Solid State Speech Circuitry The Speak and Spell was a revolutionary invention. According to Texas Instruments, it used an entirely new concept in speech recognition and unlike tape recorders and pull-string photograph records used in many speaking toys at the time, the solid-state speech circuitry it used had no moving parts. When it was told to say something it drew a word from memory, processed it through an integrated circuit model of a human vocal tract and then spoke electronically. Made specifically for the Speak and Spell, the Speak and Spell four created the first linear predictive coding digital signal processor integrated circuit, the TMS5100. In laymans terms, the TMS5100 chip was the first speech synthesizer IC ever made.

Tuesday, March 3, 2020

Every AP Chemistry Practice Test Available Free and Official

Every AP Chemistry Practice Test Available Free and Official SAT / ACT Prep Online Guides and Tips What's the best way to study for AP Chemistry? Practice, practice, practice. This article will provide you with links to every practice test and quiz for AP Chemistry that's available online, including full official and unofficial tests, shorter quizzes that cover each topic area, and other prep services you can access with a subscription! Official AP Chemistry Practice Exams Official exams are the best practice materials because they help you make accurate predictions of your performance on the real test. They will also get you used to the test format so that you're not caught off guard by the structure of the final exam. Unfortunately, for AP Chemistry, most of the available official practice materials are for the old version of the test (pre-2013), but these can still be useful for practice. You should be able to get newer practice tests from your teacher or through review books. I'd recommend starting with the unofficial practice materials listed later on in this article and then using official tests in the final stages of your studying. That way you'll be in the best position to estimate your ultimate AP score, and you won't squander limited resources. Want to get a perfect 5 on your AP exam and an A in class? We can help. PrepScholar Tutors is the world's best tutoring service. We combine world-class expert tutors with our proprietary teaching techniques. Our students have gotten A's on thousands of classes, perfect 5's on AP tests, and ludicrously high SAT Subject Test scores. Whether you need help with science, math, English, social science, or more, we've got you covered. Get better grades today with PrepScholar Tutors. Old Official Released Exams: 2008 AP Chemistry Exam 2002 AP Chemistry Exam (multiple choice only) 1999 AP Chemistry Exam 1994 AP Chemistry Exam These official exams come from before 2013 (when significant changes were made to the AP Chemistry curriculum), so they're formatted slightly differently from the current test. They have 75 multiple-choice questions (there are now 60) and six free-response questions (there are now seven). There are also five answer choices for each multiple-choice question, whereas now there are only four. The old AP Chemistry exam emphasized calculations and factual knowledge over a strong understanding of fundamental concepts and mastery of scientific practices. The questions on these tests will still help you practice your skills; just make sure you also use more recent materials for an accurate preview of what to expect on test day. Current AP Chemistry Course and Exam Description (multiple choice practice included) Go to page 126 of this course description to review sample multiple-choice and free-response questions for the current exam. This is not a full practice test (it only has 26 multiple-choice questions and four free-response questions total), but it's directly from the College Board, so it's the most accurate representation of the format and content of the test in 2016. Free-Response Questions 2014-19 These free response questions are from the most up-to-date version of the test. I would advise you to save most of them for later on in the year when you're more serious about practicing for the real AP exam. There are seven questions from each year. Free-Response Questions 2006-13 These free-response questions are from the old version of the AP Chemistry exam. As I mentioned in my description of the out-of-date practice tests above, you'll notice that there used to be six free-response questions on the test instead of seven. You should also know that the questions that ask you to write balanced equations are not on the new version of the test (doesn't mean they're not good practice, though!). Practice Tests from Your Teacher Since there aren't any full AP Chemistry practice tests available online that reflect the current format of the exam (well, any that I can legally link to in this blog post), you can also ask your teacher for additional practice materials. AP teachers have access to extra practice tests from the College Board that are available for classroom use. Oh, you need more practice tests? Maybe you should have thought of that before you interrupted all of my lectures with unnecessary questions about when I'm planning on "breaking bad." I don't even watch that show, Eric. You are a nightmare. Unofficial Free AP Chemistry Practice Exams There are also a bunch of unofficial resources for AP Chemistry practice questions on various online learning platforms and independent sites. Few of these offer complete tests in the same format as the real exam, but they do provide a large repository of practice questions (mainly multiple-choice). These are great if you're looking for questions in specific topic areas or are studying early on in the year and want to avoid certain concepts that you haven't learned in class yet. Just be wary of using these resources too much in your studying, and make sure you supplement them with official College Board materials at regular intervals. Unofficial practice questions often lack many of the nuances of real test questions. In a lot of cases, they will test straightforward factual recall whereas on the real test you'll have to do more complex analyses of unfamiliar experimental scenarios. Barron's AP Chemistry Practice Test This is a full test in the same format as the up-to-date AP exam (free response and all!). There's automatic online scoring for multiple-choice questions, and free-response answers are provided so that you can check your responses. Varsity Tutors Diagnostic Tests There are six diagnostic tests here with 50-60 questions each at varying difficulty levels. You'll also be timed as you take the tests so you can get a better sense of your pacing. Questions are multiple-choice only, so this won't give you any free-response practice. I'd also recommend trying out their AP Chemistry practice app (it's free). Albert Quizzes This site includes quizzes for each concept broken down according to the Big Ideas of the course. This site will track your progress and tell you what percentage of questions you got right from each difficulty level (questions are organized into easy, medium, and hard categories). You can also access over 200 additional questions, including free-response, if you pay $25 to set up an account. ScienceGeek Here you'll find tons of review questions and activities, with lengthy practice quizzes for each unit of the course. This is one of the few resources that has non-multiple-choice questions that you can check automatically online. PracticeQuiz This quiz includes 58 free AP Chemistry practice multiple-choice questions. ChemmyBear There's a lot of stuff here, but if you're just looking for practice tests, you can find them at the end of the list of resources for each unit. There are multiple-choice and free-response tests for most units with accompanying answer keys. Chemmy bear? Actually, there is some interesting chemistry behind how gummy candies are made. Unofficial Paid/Subscription AP Chemistry Practice Exams Here are some additional resources that will cost you some money, but they might be worth it because they provide full properly-formatted AP Chemistry practice tests. Peterson's ($29.95) Two full-length practice tests (up to date format and content) Answer explanations Automatically tells you what you still need to study based on your results 90-day access Sterling Test Prep (price varies) On this site, you can buy individual practice tests for each topic in AP Chemistry. All of them together cost almost $100, so that might not be feasible, but you can get each specialized practice test for less than $3 each (most have around 60 questions). You can also just get the Sterling book of practice questions, which many students seem to find helpful. Review Books (price varies) Review books can be great resources because many of them include instructions for how to structure your studying in addition to focused content overviews. For AP Chemistry, I recommend the 5 Steps to a 5 and Crash Course books. You can click on the link in the title of this section to read my full article on the best review books for this course. You can also get review books as e-books on your Kindle or whatever, but that's much harder to represent visually. Do you guys even know what you're looking at here? Do people under the age of 20 still read physical books? Want to get a perfect 5 on your AP exam and an A in class? We can help. PrepScholar Tutors is the world's best tutoring service. We combine world-class expert tutors with our proprietary teaching techniques. Our students have gotten A's on thousands of classes, perfect 5's on AP tests, and ludicrously high SAT Subject Test scores. Whether you need help with science, math, English, social science, or more, we've got you covered. Get better grades today with PrepScholar Tutors. How to Use AP Chemistry Practice Tests Practice tests are great study tools for AP tests, and they're especially helpful for a subject like Chemistry that involves a lot of calculations and experimental analysis. In the next couple of subsections, I'll tell you how to use practice tests throughout the school year to prepare for the AP Chemistry exam. First Semester: Using Practice Tests for Your Class It's not practical to take full practice tests during the first semester of AP Chemistry because you haven't covered enough of the course material yet. Focus on official free-response questions and unofficial topic-specific practice tests that address aspects of the curriculum that you've learned already. It's a great idea to start early and do consistent reviews so that your knowledge base remains strong throughout the year. Since chemistry is a subject that builds on the fundamental concepts learned in the first few months of class, it's vital that those early lessons are solidified in your memory. This way, more complex material that you learn second semester won't fly over your head. You can also consider getting a prep book; most of them have practice questions organized by chapter for selective review of different concepts. Second Semester: Preparing for the AP Test During your second semester, you can start to take full practice tests to predict your AP score-range. At this point, you've learned most of the material that will be covered in the class, so your scores should accurately reflect your abilities. Every time you take a full practice test, keep track of the areas where you need more practice. As I mentioned at the beginning of this article, I would recommend saving the most up-to-date official practice materials for later in the semester so that the format of the current test stays fresh in your mind. As you take each test, circle any questions where you were unsure about your answer. Even if your choice ends up being correct, you should still plan to go over these concepts, so you don't feel shaky about them on the real AP test. After you've finished taking the test (with realistic time constraints!), categorize your mistakes by topic area, and use their distribution to inform the rest of your studying. The purpose of taking practice tests is to diagnose your weaknesses so you can address them as efficiently as possible. DON'T go from one test to the next without taking a deeper look at what went wrong! You'll end up wasting your time, and your second practice test is unlikely to demonstrate much improvement. Spend at least a couple of hours after each practice test doing practice problems and reviewing concepts that you didn't quite understand when they came up on the test. When you feel satisfied that you have a better handle on the background information and solution methods, you can take a second practice test to see how much you've improved. The process as a whole should work like this: Take and score first practice test (4 hours) Evaluate mistakes (1.5 hours) Practice problems and study content to improve weak areas (2.5 hours) Take and score second practice test (4 hours) Reevaluate your progress and repeat steps if necessary! One cycle through all of these steps will take around 8-10 hours, but you can repeat the steps ad infinitum until you're satisfied with your scores. If you find that you're not improving between practice tests, you'll need to reevaluate your study strategy. To master a complex subject like chemistry, you need to have a strong grasp of the fundamental concepts. Then, you can build on that understanding for more difficult problems. Be sure to do lots of practice problems where you're required to justify your answers! The smug dude on top is you after studying with these practice tests! Just mentally replace the 1 with a 5 so that your smugness makes sense on the AP scale. Conclusion Practice tests are essential study tools, especially for AP Chemistry. Doing practice problems that align with the format and content of the real exam will help you to gain familiarity with the material and feel less stressed on test day. Try to start your studying with unofficial practice tests to build up a strong knowledge base, and then move onto official practice tests when you're ready to estimate your real AP score level. As you take practice tests, assess your mistakes and plan out your study time according to which areas need the most work. Make sure you start with basic concepts and then work your way up to more complex problems. Use these practice materials to detect gaps in your knowledge, and fill them before you take the test! What's Next? Want to learn a bit more about the test before you start practicing? Read our expert guide to the AP Chemistry exam, which includes sample questions and study tips! If you want a complete overview of the concepts that will be covered on the test, check out our ultimate study guide for AP Chemistry. We also have a specific guide to balancing chemical equations, if that's something you need extra help with. Do you plan on taking the Chemistry SAT Subject Test as well? Find out the differences between AP tests and SAT Subject Tests, and check out our Chemistry SAT II study guide article. Wondering how you can see chemistry in action in your day-to-day life? If you're looking for chemistry you can taste, we recommend these articles on vegetable oil substitutes and pozole (Mexican corn soup). If you're thinking more along the lines of something to play with, we have three different recipes for homemade slime. And if you need to clean things up afterwards, be sure to read our article on muriatic acid and how to safely use it. Want to improve your SAT score by 160 points or your ACT score by 4 points? We've written a guide for each test about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now: