What changed, and when.

New course: AP® Psychology 27 October 2026

• All five units are out, from the neuron to mental and physical health, in the order of the course framework, plus a “Research skills you need” chapter (research methods and variables, sampling, correlation, ethics, descriptive statistics, the normal curve, significance and effect size) placed just before each skill is first used. Every topic has a lesson that teaches from scratch, a free notes page and practice with an explanation for every option. Unit 1 and the research skills lessons are free. Start the course.
• The two free-response questions, part by part: the Article Analysis Studio drills the article analysis question (method, operational definition, the statistic, ethics, generalizability, the argument) and the Evidence Builder drills the evidence-based question (claim, cited evidence from two sources, reasoning with a psychology concept), each part graded with the slip named.
• Answers specific enough to score: “Make it specific” has 46 prompts across every part the two questions ask for, with builders that check each piece.
• Ten trainers that are also tests: article studio, evidence builder, the neuron, the brain map, sensation and perception, the memory lab, the conditioning lab, the statistics lab, development and social influence. The article studio, the neuron and the brain map are free.
• The May 2027 exam format: two full practice exams with 75 four-option questions in 90 minutes (with study, data and figure sets) and the two 7-point free-response questions with point-by-point rubrics and live hints, a free practice test for every unit, and a page of the statistics you must know. There is no score calculator.
• Current science, taught as science. Disorders follow the DSM-5-TR, classic studies say how well they have replicated, and myths are taught only as myths. Every unit, the trainers and the exams were checked for accuracy by an independent automated (AI) review, but no AP® Psychology teacher has reviewed the course yet. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.
• Also: the home page names all ten courses, and the Premium rules name the AP® Psychology pass with the other passes that run through a date.

A new look for every page 26 October 2026

• Every course page now matches the home page: the course’s cover art, bigger headlines and a calmer, lighter layout, in light and dark mode.
• Course homes start with three steps, then practice by domain or unit with real question counts, notes, exams and tools in one place.
• Practice, exams, review and flashcards use one clear question card with bigger answer buttons, and the progress page shows where you stand on one screen.
• Notes, glossary, pricing, search and account pages got the same look, with a contents list on long pages.

A new look for the home page 25 October 2026

• The same look as our videos, kept light and calm: every course now has its own cover art, drawn for the site rather than borrowed from a video.
• Try a question first: the home page opens with an NREMT question you can answer right there, with the explanation, before you pick a course.
• On a phone the courses are a compact list, and “Start a free practice test” stays at the bottom of the screen.

New course: AP® Environmental Science (Beta) 20 October 2026

• All nine units are out, from ecosystems to global change, in the order of the course framework, plus a “Math you need” chapter (scientific notation and metric prefixes, rates and per-capita values, unit conversions, percents and percent change, doubling time and the rule of 70) placed just before each skill is first used. Every topic has a lesson that teaches from scratch, a free notes page and practice with an explanation for every option. Units 1 and 2 and the math lessons are free. Start the course.
• Calculations graded the way readers grade them: type the setup as you would on the exam, then the answer, then its units, and each is marked on its own with the slip named (percent change without parentheses, a missing ×100, a doubling time not added to the start year). Units are read however you type them, and every key is recomputed by code.
• Answers specific enough to score: “Make it specific” has 45 prompts on hypotheses, variables and controls, cause-and-effect chains and solutions that fit the scenario, with builders that check each part.
• Twelve trainers that are also tests: calculation studio, energy flow, cycles, population growth, age structure, soil texture, Earth and climate, energy chain, air pollution, water pollution, dose and response, and climate change. The calculation studio, energy flow and cycles are free.
• The May 2027 exam format: two full practice exams with 80 four-option questions in 90 minutes (with quantitative, visual and text sets) and three 10-point free-response questions with point-by-point rubrics and a “check my number” box on calculations, a free practice test for every unit, and a page of the formulas you must memorize, since the exam gives no formula sheet. There is no score calculator.
• Beta. Every unit, the trainers and the exams were checked for accuracy by an independent automated (AI) review, but no AP® Environmental Science teacher has reviewed the course yet. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.
• Also: the home page names all nine courses, and the Premium rules name the AP® Environmental Science pass with the other passes that run through a date.

New course: AP® Statistics (Beta) 17 October 2026

• All five units of the revised course are out (first examined in May 2027), from exploring data to regression, in the order of the course framework, plus a “Math you need” chapter (fractions and percents, formulas and square roots, inequalities in words, factorials and combinations, lines) placed just before each skill is first used. Topics the revision removed are not tested. Every topic has a lesson that teaches from scratch, a free notes page and practice with an explanation for every option. Unit 1 and the math lessons are free. Start the course.
• Numbers from a table or a calculator are both right: probabilities, test statistics, p-values, degrees of freedom and intervals are checked with the tolerance each kind needs, and every key is recomputed by code. Setup questions grade the expression you would show on the exam and then its value.
• Conclusions checked part by part: build a test conclusion or an interval interpretation slot by slot and see which part is off, or write it in your own words and get hints. “Say it in context” has 36 prompts on the wording readers ask for.
• Ten trainers that are also tests: sampling distributions, data explorer, sampling lab, design randomizer, probability trees, distribution areas, interval capture, p-value explorer, chi-square lab and regression lab. Sampling distributions, the data explorer and probability trees are free.
• The May 2027 exam format: two full practice exams with 42 four-option questions in 90 minutes and four 10-point free-response questions with point-by-point rubrics, a free practice test for every unit, and the reference sheet explained. There is no score calculator: the 2027 exam is new, so no one knows its cut scores yet.
• Beta. Every unit, the trainers and the exams were checked for accuracy by an independent automated (AI) review, but no AP® Statistics teacher has reviewed the course yet. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.
• Also: the home page names all eight courses, and the Premium rules name the AP® Statistics pass with the other passes that run through a date.

22 NREMT questions corrected 14 October 2026

• NREMTAn independent review of all 2,033 questions corrected 22 questions and explanations. The Apgar score documents how a newborn is doing; it does not decide whether to resuscitate. The right ventricle pumps to the lungs, not into the veins. An implanted defibrillator does shock, and the patient still gets the AED. Partial amputations often bleed more than complete ones. The newborn steps now start with warming, drying and the airway together, and the field triage question no longer counts a GCS of 12 as a red criterion. Garbled or duplicate answer choices were rewritten, and two stems now give the finding the answer depends on.
• A&POne duplicate figure question in Cardiac muscle cells and their action potential now asks for the gap junction instead of repeating the intercalated disc question from Smooth muscle and cardiac muscle.

New course: AP® Calculus AB (Beta) 13 October 2026

• All eight units are out, from limits to volumes, in the order of the course framework, plus a “Math you need” chapter (functions, exponent rules, limit algebra, trigonometry, exponentials and logs, inverse functions, geometry) placed just before each skill is first used. Every topic has a lesson that teaches from scratch, a free notes page with the math set properly, and practice with an explanation for every option. Start the course.
• Typed answers graded by value: type a derivative or an antiderivative as an expression and it is checked at many points, so any correct form counts (with + C for antiderivatives).
• Ten trainers that are also tests: limits, tangent lines, derivative rules, related rates, motion, curve analysis, Riemann sums, accumulation, slope fields, and area and volume. The tangent tracer, the limit explorer and the rule drills are free.
• The 2027 exam format: two full practice exams with 42 multiple-choice questions, no calculator then calculator as the exam splits them, then six free-response questions with point-by-point rubrics. Also a justification trainer for the reasoning readers ask for, unit tests, a formulas and theorems page and a score calculator.
• Beta. Every unit, the trainers and the exams were checked for accuracy by a second reviewer, but no AP® Calculus AB teacher has reviewed the course yet. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.
• Every trainer, every course, on a phone: labels on pictures are at least 12 px on a small phone, handles are bigger to drag, nothing sits under the Enlarge button, and the Enlarge view re-lays the picture out to fill the screen.
• Also: the home page names all seven courses, and the Premium rules name the AP® Calculus AB pass with the other passes that run through a date.

New course: AP® Physics 1 (Beta) 13 October 2026

• All eight units are out, from kinematics to fluids, in the order of the 2024-25 course framework, plus a “Math you need” chapter (units and significant figures, working with symbols, proportional reasoning, slopes and areas of graphs, trigonometry and components) placed just before each skill is first used. Every topic has a lesson that teaches from scratch, a free notes page, and practice with an explanation for every option. Start the course.
• A free-body diagram builder: drag forces onto an object in a real scene and get each force graded, with the misses readers see most often named (an extra force, a missing normal force, the net force drawn as a force). It is free, with the motion graphs trainer and the scaling drills.
• Eleven trainers that are also tests: motion graphs, projectiles, energy bar charts, collisions, torque, rotation, oscillators, fluids, lab design and scaling. Each opens on a live scene to explore, then a “Test yourself” drill with fresh numbers every time, checked by the same code you run.
• The 2027 exam format: two full practice exams with 42 multiple-choice questions in 85 minutes, then the four free-response types in order (mathematical routines, translation between representations, experimental design, qualitative and quantitative translation), with point-by-point rubrics. Also a justification trainer, unit practice tests, an equations-sheet walkthrough and a score calculator.
• Beta. Every unit was checked for accuracy by a second reviewer, but no AP® Physics 1 teacher has reviewed the course yet. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.
• Also fixed: the home page now names all six courses, and the Premium rules name every pass that runs through a date (AP® Biology, AP® Chemistry and AP® Physics 1), not only AP® Biology.

New course: AP® Chemistry (Beta) 6 October 2026

• All nine units are out, from atomic structure to electrochemistry, in the order of the 2024 course framework, plus a “Math you need” chapter (units, exponents, scientific notation, significant figures and logs) placed just before each skill is first used. Every topic has a lesson that teaches from scratch at the particle level, a free notes page, and practice with an explanation for every option. Start the course.
• Practice that grades like a reader: numeric answers are checked for value, units and significant figures separately, with feedback on the slips the exam punishes (kJ vs J, °C vs K, ln vs log).
• Six trainers: particle diagrams, ICE tables, Q vs K, buffers, a titration curve reader, and units and significant figures. The numbers are generated fresh every time and checked by the same code you run.
• A justification trainer for the free-response “explain” and “justify” prompts, free-response questions with point-by-point rubrics, two full practice exams in the real 60-question and 7-question format, unit practice tests, an equations-sheet walkthrough and a score calculator.
• Beta. Every unit was checked for accuracy by a second reviewer, but no AP® Chemistry teacher has reviewed the course yet. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.

AP® Biology: a new course home 6 October 2026

• The course home now works like the other courses’: your level and streak, what to do next, a path through the eight units and the skills track that shows where you are, the simulators (osmosis is free) and a real question to try. Open the course.

AP® Biology: Unit 8, the full course 3 October 2026

• Unit 8, ecology: responses to the environment, energy flow, population growth and density, communities, biodiversity and ecosystem disruption, with six new free-response questions. Simpson’s diversity index in the skills track opens with it. See the course.
• Two new simulators: exponential and logistic population growth with disturbances, and energy and biomass pyramids with a biomagnification mode.
• A cram kit: a 3-week or 2-week plan counted back from your exam date, weighted by unit and by your weakest topics, with timed mixed sets at exam pace and two full practice exams placed in the plan. Open the cram kit.
• All eight units are now published, so unit tests and full practice exams draw on the whole course. The course stays in Beta until an AP® Biology teacher has reviewed it.

AP® Biology: Unit 7 and design drills 3 October 2026

• Unit 7, natural selection: selection and its evidence, Hardy-Weinberg, drift and gene flow, common ancestry, phylogenetic trees, speciation and the origin of life, with six new free-response questions. The Hardy-Weinberg lesson and calculator in the skills track open with it. See the course.
• Two new simulators: populations drifting, selected and bottlenecked, with a seed so a run can be repeated; and reading and building phylogenetic trees by keyboard.
• Experimental design drills are complete: 16 experiments across the course, each with its data, drilling variables, controls, null hypotheses, claim-evidence-reasoning and prediction with mechanism.

AP® Biology: Unit 6 3 October 2026

• Unit 6, gene expression and regulation: DNA and RNA structure, replication, transcription and RNA processing, translation, gene regulation, cell specialization, mutations and biotechnology, with codon tables, gels and replication data to read, and five new free-response questions. See the course.
• A lac and trp operon simulator: set the sugars or tryptophan, add repressor and operator mutations, and watch mRNA and enzyme levels respond.

AP® Biology: Unit 5 3 October 2026

• Unit 5, heredity: meiosis and genetic diversity, Mendelian and non-Mendelian inheritance, linkage and gene maps, and how the environment shapes phenotype, with pedigrees, crosses tested with chi-square and five new free-response questions. See the course.
• A meiosis simulator: step a cell through both divisions, switch crossing over on, choose how pairs line up, and make a pair fail to separate to see the gametes that result.

AP® Biology: Unit 4 3 October 2026

• Unit 4, cell communication and the cell cycle: signaling over short and long distances, signal transduction and its amplification, feedback, the cell cycle and its checkpoints, with lessons, free notes, question sets and four new free-response questions. See the course.
• Two new simulators: a hormone signal amplified through a G protein pathway, with steps you can block, and a population of dividing cells passing its checkpoints, with mutations you can switch on.

New course: AP® Biology (Beta) 3 October 2026

• Units 1 to 3 are out: chemistry of life, cell structure and function, and cellular energetics, in the order of the 2025 course framework. Each topic has a lesson that teaches from scratch, a free notes page, and data-heavy practice: standalone questions and sets of questions on one table, graph or experiment, with an explanation for every option. Start the course.
• A skills track for the formula sheet and the free-response section: mean, standard deviation and standard error, confidence intervals and error bars, chi-square, rates, water potential, graph construction, and drills on variables, controls, null hypotheses and claim-evidence-reasoning.
• Free-response practice with point-by-point rubrics, sample answers and printable answer sheets; two simulators (osmosis and water potential, enzyme activity); unit tests and a practice exam in the real format.
• For teachers: every lesson, notes page, question set and free-response question has a stable link, a Share to Google Classroom button and a printable version. Students need no account. See For teachers and the new For schools section of the privacy page.
• Beta. Every unit was checked for accuracy by a second reviewer, but no AP® Biology teacher has reviewed the course yet. Units 4 to 8 follow one at a time. AP® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.

Free vs Premium, said plainly 2 October 2026

• One sentence about what is free, used everywhere. All notes and textbook pages are free forever; interactive lessons are free in the early chapters; Premium adds unlimited practice, exams, every lesson and analytics. Some pages still said the teaching material was free “permanently” or that every A&P lesson was free, which stopped being true when Premium launched. The new Free vs Premium page lists both sides for each course, with prices.
• The NREMT “pass guarantee” is now called Pass-or-extend, which is what it is: a free 90-day extension if you don’t pass, with conditions. The conditions are now shown in the purchase dialog, and the terms say plainly that a practice exam counts only when it is finished while signed in.
• Wrong numbers fixed: the Organic Chemistry purchase dialog said 3,795 questions (the bank holds 3,635), the page-not-found page said sixty-two topics (there are 121), and the course’s app description said 14 modules (there are 23 chapters). The terms and privacy pages are dated 1 October, the day Premium went on sale.
• A&PThe Sources page now describes the A&P course as complete. It still said the Beta had only the foundations and the cardiovascular system. The Beta label stays until a licensed instructor has reviewed the course.
• The privacy page now covers question reports and the study assistant in full: what a report holds, what an AI answer sends (your question, the matching passages, the last four turns and the course) and that AI answers now need a sign-in.
• History moved here from the legal pages. Three paragraphs on the Privacy and Sources pages recorded their own past mistakes: the email paragraph once said the site sent no email at all (until password resets were added) and later that there was no product email (until study reminders were); the typefaces were served by Google Fonts, so Google saw visitors’ IP addresses, for longer than the page admitted; and the Organic Chemistry scope paragraph called the course one-semester after the Organic Chemistry II chapters were written, and listed thirteen chapters after there were twenty-three. The site also promised a way to report a mistake well before the Report a problem link existed. The legal pages now describe how things are, and this log keeps the history.

Premium is live 1 October 2026

• Every course is free to start, the same way. 15 practice or review questions a day, one full timed exam, all notes, flashcards and your progress; none of it needs an account. Ochem’s first 4 chapters and A&P’s first 5 stay fully open.
• Premium is a one-time pass, never a subscription. $29 for 90 days of NREMT or a semester of ochem or A&P, $49 for a full year; 30% off for founding members until 31 January 2027. Accounts made before launch got 30 days of Premium free in every course (the founding-member free month).
• Your Account page shows your passes, lets you refund one yourself within 7 days, and is where you claim NREMT Pass-or-extend (then called the pass guarantee): don’t pass the exam during your pass and get a free 90-day extension. The terms have the details.

A&P leaves Beta; Premium is marked 1 October 2026

• A&PAnatomy & Physiology is out of Beta. All 27 chapters are live. It still follows current published sources and has not yet been reviewed by a licensed instructor, so the report link on every question matters as much as ever.
• Premium is coming, and you can already see what it will include. Every course now marks its Premium features with a small pill. Nothing is locked yet and everything stays free until Premium launches. After that, all notes stay free for good, as does the first part of every course, and Premium becomes a one-time pass with no subscription. The terms explain passes and refunds.

A&P: muscle tissue 24 September 2026

• A&PThe muscle tissue chapter is live: how a skeletal muscle is built from fascicles, fibers, myofibrils and sarcomeres, the neuromuscular junction, excitation–contraction coupling, the cross-bridge cycle and rigor mortis, twitches, summation, tetanus, motor units and the length–tension relationship, how muscle remakes ATP and why it tires, the three fiber types and how training changes them, and smooth and cardiac muscle. The lab practical gains skeletal muscle organization, sarcomere, neuromuscular junction and muscle histology stations, the calculators gain sarcomere, band width, fiber shortening, energy store and glucose-per-ATP tools, and the other tools gain twitch, summation, length–tension, energy system and smooth muscle stretch graphs, pathways from an impulse at the junction to relaxation and from glycogen to lactate, and prediction scenarios from a curare-type drug to a loop of intestine cut off from its nerves.

A&P: joints 24 September 2026

• A&PThe joints chapter is live: classifying joints by structure and by how much they move, synovial joints and their six types, the shoulder, elbow, hip, knee, jaw and ankle, osteoarthritis and knee injuries, and the names of body movements. The lab practical gains synovial joint, knee and body movement stations, and the other tools gain joint angle and cartilage loading graphs, pathways from classifying a joint to how an ACL tears, and prediction scenarios from the pubic symphysis in pregnancy to a rear-end car crash.

A&P: the skeleton 24 September 2026

• A&PThe skeleton chapter is live: the skull (cranial and facial bones, sutures, openings, sinuses and fontanelles), the vertebral column and its curves, the thoracic cage, and the bones of the pectoral girdle, upper limb, pelvic girdle and lower limb, including how the pelvis differs between the sexes. The lab practical gains skull, vertebrae, thoracic cage, upper limb, lower limb and whole skeleton stations, and the other tools gain pathways from the skull floor to the arches of the foot, prediction scenarios from a blow to the temple to a broken ankle, and word parts for the chapter’s bone names.

A&P: bone tissue 24 September 2026

• A&PThe bone tissue chapter is live: bone structure and markings, bone cells and compact and spongy bone, how bone forms and grows in length at the growth plate, remodeling and fracture repair, and how bone holds blood calcium steady. The lab practical gains long bone, bone histology and growth plate stations, the calculators gain a daily calcium balance tool, and the other tools gain bone mass, growth rate and calcium hormone graphs, the blood calcium and Wolff’s law loops, pathways from a bone-forming cell to fracture repair, and prediction scenarios from a bone soaked in vinegar to a medicine that slows osteoclasts.

A&P: the integumentary system 24 September 2026

• A&PThe integumentary chapter is live: the layers of the skin and what gives it color, hair, nails and the skin’s glands, how the skin protects you, senses, controls body temperature and makes vitamin D, and wound healing, burns, skin cancer and common skin disorders. The lab practical gains skin layer, thick skin and hair follicle stations, the calculators gain sweat cooling, rule of nines and palm method tools, and the other tools gain heat loss, wound strength and hair growth graphs, the skin’s too-warm and too-cold loops, pathways from a keratinocyte’s journey to skin cancer, and prediction scenarios from a week at the beach to a large burn in its first hours.

A&P: the muscular system 24 September 2026

• A&PThe muscular system chapter is live: how muscles move bones (origins and insertions, prime movers and antagonists, levers, fascicle arrangements and muscle names), then the muscles of the head and neck, the trunk, the upper limb and the lower limb, with fascial compartments and the intramuscular injection sites. The lab practical gains head and neck, trunk, upper limb, lower limb and injection site stations, the calculators gain muscle pull and load movement lever tools, and the other tools gain lever and compartment pressure graphs, pathways from a shortening fiber to a moving bone to finding the ventrogluteal site, prediction scenarios from a torn supraspinatus to foot drop, and word parts for the chapter’s muscle names.

A&P: development and inheritance 24 September 2026

• A&PThe development chapter is live: fertilization, embryonic development, the placenta, fetal development and fetal circulation, the mother’s body in pregnancy, labor and birth, the newborn and lactation, inheritance, and aging. The lab practical gains blastocyst and implantation and placenta and fetal circulation stations, the calculators gain weeks-of-pregnancy, placental oxygen transfer, pregnancy blood pressure, Apgar, Punnett square, X-linked inheritance and maximum heart rate tools, and the other tools gain pregnancy hormone, fetal growth, maternal circulation, trisomy 21 and reserve-with-age graphs, the labor and newborn brown fat loops, pathways from fertilization to milk ejection, and prediction scenarios from a patent ductus to resistance training at 70.

A&P: the reproductive system 24 September 2026

• A&PThe reproductive chapter is live: meiosis and gametes, male reproductive anatomy, spermatogenesis and male hormones, female reproductive anatomy, oogenesis and the ovarian cycle, and the hormonal control of the ovarian and uterine cycles. The lab practical gains male and female reproductive anatomy and sperm and testis stations, the calculators gain gamete combination, spermatogenesis count and ovulation-day tools, and the other tools gain a 28-day hormone and endometrium graph, testosterone, inhibin and LH-surge loops, meiosis, sperm and follicle pathways, and prediction scenarios from vasectomy and anabolic steroids to the combined pill.

A&P: fluid, electrolyte and acid–base balance 24 September 2026

• A&PThe fluid, electrolyte and acid–base chapter is live: body fluid compartments and water balance, electrolyte balance, regulating acid–base balance, and acid–base disorders and compensation. The calculators gain a stepwise arterial blood gas interpreter, anion gap, Winter’s formula, plasma osmolality, adjusted calcium and fluid compartment tools, and the other tools gain ADH and thirst, blood pH and new-bicarbonate loops, renal acid pathways, and prediction scenarios from vomiting and diarrhea to diabetic ketoacidosis.

A&P: the urinary system 24 September 2026

• A&PThe urinary chapter is live: the kidneys and urinary tract, the nephron, glomerular filtration, tubular reabsorption and secretion, concentrating the urine, and clearance and kidney hormones. The lab practical gains kidney, nephron and urinary tract stations, and the calculators gain filtration pressure, GFR, clearance and transport-maximum tools.

A&P: metabolism and nutrition 24 September 2026

• A&PThe metabolism and nutrition chapter is live: nutrients, vitamins and minerals, carbohydrate, lipid and protein metabolism in detail, the fed and fasting states, and energy balance and body temperature. The tools gain energy and ATP calculators, fasting and heat-loss graphs, and the full temperature-control loops.

A&P: the digestive system 24 September 2026

• A&PThe digestive chapter is live: the organization of the gut, the mouth and esophagus, the stomach, the small intestine, the liver, gallbladder and pancreas, the large intestine, and chemical digestion and absorption. The lab practical gains digestive tract, gut wall, teeth, stomach and liver stations, and the tools gain gut hormones, gastric emptying, a breath test graph and water-balance and surface-area calculators.

A&P: the lymphatic and immune systems 24 September 2026

• A&PThe lymphatic and immune chapter is live: the lymphatic system, innate immunity, antigens and antigen presentation, T cells, B cells and antibodies, and immune disorders from allergy to HIV. The tools gain the fever loop, antibody response and HIV graphs, and lymphatic organ and lymph node lab stations.

A&P: the endocrine system 24 September 2026

• A&PThe endocrine chapter is live: how hormones act, the hypothalamus and pituitary, the thyroid and parathyroid glands, the pancreas and blood glucose, the adrenal glands, and the other endocrine organs. The tools gain the glucose, thyroid, cortisol and calcium feedback loops, the renin–angiotensin–aldosterone pathway, a glucose and insulin graph, and an endocrine gland lab station.

A&P: blood 24 September 2026

• A&PThe blood chapter is live: blood composition, red blood cells and hemoglobin, white blood cells and platelets, hemostasis and clotting, and blood types and transfusion. Clotting is taught with the current cell-based model, with the lab pathways you will see on exams. The tools gain blood calculators (hematocrit, blood volume, red cell production, absolute neutrophil count), the clotting and erythropoietin loops, and a formed elements lab station.

A&P: special senses and the autonomic nervous system 24 September 2026

• A&PTwo more nervous system chapters are live: the special senses (taste and smell, vision, hearing and balance) and the autonomic nervous system (its anatomy, transmitters and receptor proteins, and how it controls the organs). The lab practical gains eye, ear and sympathetic chain stations, and the graph reader gains dark adaptation, the audiogram and autonomic blockade.

A&P: the peripheral nervous system 24 September 2026

• A&PThe peripheral nervous system chapter is live: spinal nerves and plexuses, the cranial nerves, sensory and motor pathways, reflexes and the neurological exam. The lab practical gains cranial nerve, brachial plexus and dermatome stations, and the calculators gain reflex delay and the Glasgow Coma Scale.

A&P: nervous tissue and the central nervous system 23 September 2026

• A&PTwo nervous system chapters are live: nervous tissue (organization, neurons and glia, the action potential in detail, synapses) and the central nervous system (brain regions, the meninges and cerebrospinal fluid, the spinal cord, and higher functions such as memory, language and sleep). The lab practical gains neuron, glia, brain, meninges and spinal cord stations, and the other tools gain nervous system items.
• A&PThe tools now show only chapters that are published, so items still being checked no longer appear early.

A&P: the respiratory system 23 September 2026

• A&PThe respiratory chapter is live: nine topics from the nose to the alveoli, the mechanics of breathing, gas exchange, oxygen and carbon dioxide transport, and the control of breathing, each with a lesson, full notes and practice questions. The lab practical gains four stations (nose, larynx, bronchial tree and alveoli), and predict the change, the pathway tracer, the graph reader and the calculators gain respiratory items.

A new course: Anatomy & Physiology (Beta) 23 September 2026

• A&PThe first part of a full two-semester anatomy and physiology course is live as a Beta: the foundations (orientation to the body, chemistry and physics for physiology, cells, tissues, signals and homeostasis) and the whole cardiovascular system. Every topic has an interactive lesson and a full notes page, and they are built in an order where no page uses a term before the lesson that teaches it.
• A&PTools built for physiology reasoning: a virtual lab practical on real figures, predict the change, a feedback loop builder, a pathway tracer, a graph reader, worked-example calculators and a word root builder, plus practice, spaced review, exams with a TEAS A&P practice mode, flashcards and a mastery dashboard.
• SiteThe course follows current published sources and is pending review by a licensed A&P instructor. Where the science has moved on, it teaches the current explanation and notes the older answer an exam may still expect. Figures from OpenStax are used under CC BY 4.0 and credited on each figure.

Corrections checked against published guidelines 22 September 2026

• NREMTThe questions the accuracy review could not fix with a word change are rebuilt, each against current published guidance: the 2025 AHA/AAP neonatal guideline, the NASEMSO National Model EMS Clinical Guidelines, the 2019 National EMS Scope of Practice Model and the standard definitions they rest on. Epinephrine for anaphylaxis no longer asks for a prior reaction. The sepsis screen now lists the actual SIRS criteria and says which extras are EMS additions. The formulary is the seven core drugs, not all of them. Delivery no longer suctions between head and shoulders, an open chest wound is sealed before you listen, and the blood-loss, airway-adjunct and carbon-monoxide questions each have one defensible answer.
• OchemThe remaining chemistry items were checked against standard texts and IUPAC rules. The acyl substitution and Claisen mechanisms now draw the tetrahedral intermediate the collapse step happens on, and E2 arrows run from bond to bond.
• SiteThese corrections follow current published guidelines but have not yet had formal review by a licensed EMT or paramedic instructor. A few where sources disagree or protocols vary are marked for that review. If your local protocol says otherwise, follow your protocol.

Every page checked for accuracy 22 September 2026

• NREMTAbout 160 explanations pointed at the wrong answer. They named answers by position — “option 3”, “choice B” — but practice shuffles the answers for every student, and most of the numbers did not match even the stored order. In about forty the reference landed on the correct answer and called it wrong. Every one now names the answer it means by what it says.
• NREMTClinical corrections across the bank, the notes and the reference pages, 214 questions in all. Status epilepticus is five minutes in the notes too. A flail segment is two or more ribs, not three. The OPA landmarks were swapped. Trendelenburg is head-down, not legs-up. An arrow is a low-velocity weapon. Children have more blood per kilogram than adults, not less. Rehab sits in the cold zone. The pelvic binder goes over the greater trochanters, not the iliac crests. Tourniquets go 2–3 inches above the wound, pregnant cardiac arrest uses the standard hand position with the uterus pushed aside, and the skill-sheet page lists ten stations because there are ten.
• OchemCorrections in 58 textbook sections, 42 lessons, four mechanisms and 94 practice questions. A figure labeled 2-methylbutanal drew 3-methylpentanal. The Wolff–Kishner mechanism lost N₂ in the wrong order. The rate-determining step is the highest transition state, and one lesson question was keyed to the other one. Diisopropylamine does not shuttle protons between enolates; leftover ketone does. PET and nylon are below their T_g at room temperature, not above it. Isobutyl, 2-methyl-2-butene and a bicyclo[3.3.1] ring now carry their right names.
• OchemTwo tools gave wrong answers. The reaction predictor called benzyl bromide with KOtBu, and ammonia with a secondary halide, S_N1 — both are S_N2. The conformation lab’s 2-methylbutane curve had the wrong symmetry, and it said cyclohexane flips billions of times a second (about a hundred thousand is right).
• SiteEvery correction was proposed by one reviewer and checked by a second before it went in; the ones that need a new drawing or a rewritten question are listed for the author rather than patched.

A map of every reagent in the course 22 September 2026

• OchemAn eighth tool: the Reagent Roadmap. Pick where you start and where you need to end up — propan-2-ol to propan-1-ol, say — and it finds the shortest routes, with the reagents, the regio- and stereochemistry and the section that teaches each step. It can also look up everything one reagent does, or show what a group becomes, what makes it and what does not work on it. The routes are honest about substrates: an alkene made from a tertiary alcohol has no H on one carbon, so the map will not pretend it can become an alkyne.
• OchemThe “Not quite” label under a wrong quiz answer, in every tool, was amber text on an amber tint at 2.3:1 contrast. It uses the darker amber the tags use now, and a tool page is on the accessibility check’s list so the next one is caught.

Flashcards for Organic Chemistry 22 September 2026

• OchemThere is a flashcard deck now, under its own tab next to Review. Every concept in the course, the pKa, IR and NMR values, reagent menus and comparison tables from the notes, and the named reactions — 663 cards, filterable by chapter, by card type, and to the topics you have studied or the ones practice says you are shaky on. Grade each card Again, Hard, Good or Easy and it comes back just before you would forget it; twenty new cards a day, so the deck grows at a pace you can keep. Flip with a tap, Space or a swipe; every card links back to the section that teaches it. The cards are read out of the notes rather than typed out again, so a value corrected in the notes is corrected on its card. Your schedule syncs with your account and earns a little XP for the cards you review on schedule. Open the deck.

Practice that asks you to do the chemistry 22 September 2026

• OchemOxidation & Reduction now asks what happens, not what things are called. 50 recall questions across the five redox sections are replaced by ones that hand you a molecule and a reagent: NaBH₄ or LiAlH₄ on a keto-ester, PCC and Jones on the same alcohol, DIBAL-H at −78 °C on an ester, oxidation states counted on real molecules, and three-step “what is Z” problems.
• OchemSpectroscopy gives you the spectrum. 40 new questions hand you the data — IR bands, ¹H shifts with integration and splitting, ¹³C counts with DEPT, molecular ions, isotope patterns and fragments, UV λ_max — and ask which structure fits. They replace questions that asked what each technique measures, and they use the same values the notes teach.
• Ochem100 one-line explanations in the enolate sections are now real ones, saying why the answer is right and why the tempting wrong answers are wrong. Rewriting them turned up three questions that needed fixing: one keyed a rule the chapter had already retired (thermodynamic control needs the enolates to interconvert, not the deprotonation to reverse), one overstated how badly malonate handles a secondary halide, and one left a second reaction open that made a wrong answer defensible.

Three structures the notes named and never drew 22 September 2026

• OchemSuccinic anhydride, the β-lactam and a polymer taken apart are now drawn. The cyclic-anhydride paragraph gets its four structures, from succinic acid through the amic acid to succinimide. The β-lactam paragraph gets an ordinary amide, the four-membered ring and penicillin side by side, with the enzyme’s serine opening the ring. Polymer design gets polypropylene, PET and nylon 6,6 cut back to their monomers, with the PET cut to avoid marked. The polyamide rule now says which C–N bond to cut: the amide one, not the bond to the CH₂.

Forty corrections, and three more checks 15 September 2026

• NREMTSeven answers were simply keyed wrong. SLUDGE listed sweating instead of lacrimation. A choking two-year-old was keyed to the infant sequence of back blows and chest thrusts, when a child that age gets abdominal thrusts. Two START questions were wrong in opposite directions: a walking-wounded exclusion keyed red when it is yellow, and a patient with agonal breathing and no radial pulse keyed expectant, when under START anyone still breathing is immediate. An APGAR scored 8 when the stem totals 7 — and 7 was not even offered. Status epilepticus said ten minutes; the definition is five, which another question in the same bank already used.
• NREMTFive questions had the previous question’s answer options. A question about a shallow-water diving injury offered four options about blood pressure. The stems and the explanations were right and untouched, which is why nobody caught it — the file parses, the ids are unique, every count matches. The explanations described the intended wrong answers closely enough to rebuild all five.
• NREMTEleven pairs of questions contradicted each other, so a student meeting both was marked wrong on one. Suction time, OPA sizing, shock positioning, helmet removal, flail chest, red lights, chest seals, oxygen at 88%, and whether bleeding or airway comes first. Each now has one answer, and where the notes disagreed the notes changed too.
• NREMTGuidance that had gone stale: a significant fall is more than 10 feet, not 20. Burns get about twenty minutes of cool running water, not “a brief period”. Newborns are no longer routinely suctioned. A palpable pulse during compressions is not evidence the compressions are working, and was keyed as if it were. Bleeding from a dialysis fistula gets firm pressure — the old answer told you not to fully occlude it, which is advice that can cost a patient their life to save a fistula.
• NREMTQuestions about intubation, capnography and 12-lead interpretation now say whose hands are on the equipment, since none of it is EMT scope. The knowledge is worth having when you are the one ventilating; pretending it is your skill is not.
• SiteA third answer tell, and this one was ours. Fixing the “longest answer is correct” tell moved explanation out of the keys and into the wrong answers, where it lands as a clause explaining why the option is wrong. On 182 questions exactly one option carries such a clause, and it is the answer 17% of the time against a 25% baseline. An option that argues against itself is rarely the key, and that is a third free rule for anyone who notices. It is now measured on every build, alongside a check that no question can inherit its neighbor’s options again.

Four checks, and the things they found 15 September 2026

• NREMTThe notes and the questions disagreed about oxygen for COPD, and now they do not. Chapter 10 taught that too much oxygen suppresses a COPD patient’s drive to breathe, while the questions correctly said a hypoxic COPD patient still gets oxygen. Both are now the same rule: the physiology is real, it is a reason to titrate toward the patient’s own baseline, and it is never a reason to withhold oxygen from someone who is hypoxic.
• NREMTBleeding control taught the wrong first move. The notes ran direct pressure → packing → tourniquet as one ladder for everything. Life-threatening extremity bleeding does not climb the ladder — it gets a tourniquet immediately — and the motorcycle scenario now scores it that way rather than rewarding a worked-up escalation. Elevation is gone from bleeding control entirely; it delayed the pressure that actually works.
• NREMTThe stroke scenario scored a glucose check as a mistake, which contradicted the notes and the flow diagram. Hypoglycemia is the classic stroke mimic. The screen still goes first because it takes thirty seconds and needs nothing but your eyes, but the glucose now happens on the best path instead of never happening at all.
• NREMTTwo answers were fixed rather than the bank around them: one told you to withhold glucose or give it, which is not an answer, and the tourniquet question made a tourniquet conditional on direct pressure failing first. The body map now names the liver under the lower right ribs, not just the spleen under the left, and stops calling every temporal fracture a basilar skull fracture — they are two different injuries with two different presentations.
• OchemSeven molecules were drawn with methyl groups missing a hydrogen, acetone among them — a course whose first module is counting bonds was shipping structures that fail the count. All seven are fixed, and a valence check now fails the build on any recurrence. Drawings that deliberately show only the hydrogens under discussion, like the chairs, say so in the file.
• OchemThe SN2 walkthrough numbered its intro card as a step, so every card read one ahead of its own heading — “Step 2 / 9” above “Step 1 · Identify”. The step rail also labeled itself from each step’s question stem, so it filled with sentences cut off mid-question and fell back to a bare “Step 2” where a step had no stem; it uses the short eyebrow now.
• OchemAniline cannot simply be nitrated, and the directing-effects section implied it was the fastest substrate going. Nitrating acid protonates the amine to a deactivating meta director. The workaround — acetylate, nitrate, hydrolyze — is now spelled out, because it is exactly what gets asked. The pKa table also had the 1,3-diketone filed below phenol despite being more acidic.
• SiteFour new checks run on every build: a valence check on molecule drawings, two answer-wording checks, and a scenario graph check. The wording ones measure a tell the position and length checks could not see — on 441 questions exactly one option contained an absolute word like “always” or “never”, and that option was the answer 6.6% of the time against a 25% baseline. A student who learns that one rule can eliminate an option on a fifth of the bank. Like the other ceilings, these start at what was measured, not at the target, so the number cannot get worse while the rewriting happens.

Telling us when something is wrong, and being told when something is due 15 September 2026

• BothThere is a “Report a problem” link under every explanation now — in the results list after an exam, on the back of a flashcard, and under each Organic Chemistry question. Pick what is wrong from four options, add a sentence if you want to, send. No account needed and nothing about you is recorded with it. Sources promised a way to do this from the day it was written and never actually gave one; the only address on the site was at the bottom of the privacy policy.
• BothThe site can remind you when something is due. One notification a day, at a time you pick, and only when you genuinely have questions waiting or a streak about to lapse — it stops by itself after three unanswered days. Off unless you turn it on, in Privacy. The number in it is worked out in your browser; we are told a number and a sentence, not what you have been studying.
• SiteYou can delete your account yourself, from the account menu. It used to be an email request. The same screen offers you a backup file first and can erase this browser’s copy too, since your progress lives in both places and almost nobody expects that.
• OchemA search page for the whole course — the textbook, all 58 lessons, the mechanism walkthroughs, the seven tools and every practice question, in one box. The textbook rail could already search its own prose, but nothing could find a lesson, a mechanism or a tool, so working out where something was explained meant guessing.
• SiteSeveral colors were hard to read and now are not. The green used for small labels and buttons failed the contrast standard for text, as did the amber in the “watch out for this” boxes in the Organic Chemistry notes — which were, by some distance, the least readable thing on the site. Both are darker now.
• OchemThe 3D figures in the textbook carried 208 keyboard stops that did nothing — the atoms are clickable in the tools, and the textbook was reusing pictures of them. Tabbing through a chapter now goes where you would expect, and the wide figures can be scrolled from the keyboard.
• SiteThe privacy policy was wrong about two things, and is not now. It still named Google Fonts as serving the typefaces and receiving your IP address with every page — they have been served from this site for some time, and no font service is contacted at all. It also undersold signing in, saying it carried only your XP and streak: it carries the questions you have seen, what you missed on a timed exam, your mastery, your per-domain statistics and the textbook sections you have read. A page whose only value is being true is a bad page to leave stale.
• OchemFour pages linked to the amines lesson with the label “Reactions”, which says nothing when you meet it at the bottom of a mechanism about something else. It reads “Amine reactions” now, fixed in the curriculum the pages are built from rather than one page at a time.
• NREMTThe line under the heading on What the exam is like had been half-edited into nonsense — the same sentence twice, one paragraph opened inside another, and a stray mdash; where an em dash was meant.
• SiteCorrections to questions are the point of the report link above; when one is made it is listed here, dated, as it always has been.

Coming back is easier than it was 14 September 2026

• BothA streak now survives one bad day. Study seven days in a row and you earn a streak freeze: miss a single day and the run keeps going. You hold one at a time, and it is only spent when you come back and study — opening a page never uses it up.
• BothThe daily goal eases off after a rough patch. Miss a couple of days and it halves, so coming back is possible rather than hopeless, then returns to your own number once you are studying again. If you set the goal yourself, it is never moved.
• NREMTThe home page now leads with whatever is waiting for you — an exam you left half-finished, or the questions your own answers say are slipping — and takes you straight into it instead of onto the start screen. The review queue was always there; it was two screens in and easy to miss.
• OchemWhen something is genuinely due for review, it is now the main button on the home page and the lesson steps back. A queue that keeps waiting is a queue of things you are in the middle of forgetting; a half-finished lesson is not.
• BothAdding the site to your home screen works properly on iPhone. The icon was an SVG, which iOS quietly refuses, so an installed copy showed a screenshot of whatever page you happened to be on. There are real icons now, and ochem and the landing page can be installed too — not just NREMT.
• BothThere is now a prompt offering to save your progress to an account, shown after a level-up or a finished exam rather than on arrival. Everything still works without one; the point is that progress kept only in a browser disappears when you clear it or switch phones, and nothing used to warn you.
• SiteThe site now records, once a day at most, whether this browser has been back before — as a coarse band rather than a date, with the dates behind it never leaving your browser. Privacy says exactly what is sent, and the existing off switch covers it.

Seven corrections to the notes 14 September 2026

• NREMTPediatric Rule of Nines. The figures given for a child omitted the arms and added up to 82%. They now read as they do on the mnemonics card — head and neck 18%, each leg 13.5%, everything else as in an adult — and total 100%.
• NREMTScoop stretcher. The carrying-device table said it was not for a suspected spine injury. The joint position statement of the American College of Surgeons Committee on Trauma, the American College of Emergency Physicians and the National Association of EMS Physicians lists the scoop stretcher as a device for achieving spinal motion restriction, so the table now says so.
• NREMTAnaphylaxis in infants. The notes said infants seldom have true anaphylaxis because the immune system is immature. That is not right: it happens, it is missed more often than it is absent, and epinephrine is under-used in that age group. Age is never a reason to withhold it.
• NREMTHIV post-exposure prophylaxis. The 28-day course was described without its time window. It has to start as soon as possible, ideally within hours and never later than 72 hours.
• NREMTThe midaxillary line ran “down to the ankle”. It is a landmark of the torso: down from the armpit, over the side of the chest and along the flank.
• NREMTSTART triage. Red was a respiratory rate above 30 and yellow a rate below 30, which left a rate of exactly 30 in neither category. Yellow is now 30 or less.
• NREMTA soft-tissue key point contradicted itself on cooling an amputated part, and a chapter heading read “gastrourinary”. Both are fixed.

The notes are written as a textbook 14 September 2026

• NREMTEvery one of the forty chapters has been rewritten as prose. The notes were largely "term — fragment" bullets and arrow chains; they are now paragraphs that explain, in the register of a course textbook. Every fact, figure, name and mnemonic is unchanged, and the tables are untouched. Lists remain where a list is the honest form: the steps of a procedure, a set of criteria, named categories, the medications you carry.

The notes as a textbook 13 September 2026

• NREMTThe study notes now read as a textbook. Every chapter opens with a short introduction, its number set large and an "In this chapter" contents box; sections are numbered (14.1, 20.2) in the rail, the headings and the running head that follows you down the page; tables carry numbered captions; the prose is set in a serif at reading weight.
• NREMTEach chapter ends with its key terms, drawn from the glossary, and five review questions from the bank for the ground the chapter covers, with the explanation shown once you answer. "Another five" gives a fresh set.
• NREMTPrinting the notes now produces the whole book: a cover, a contents page, and every chapter on a fresh page.

Performance, trust and content pass 13 September 2026

• NREMT480 questions edited so the longest option is no longer a tell. The correct answer was the longest option 54% of the time; it is now 30%, and the check that guards it only tightens. Keys and explanations are unchanged. One trauma question (the shock patient asking for water) had the wrong option set attached and now has the right one.
• NREMTNew About the exam page: adaptive format, the two-hour limit, cost, eligibility, retake rules and what to bring.
• NREMTA print or save as PDF button on exam results.
• SiteNew Sources page on who makes this and what the material is written against; it and this page are linked from every footer.
• SitePages paint much sooner: every script is deferred and the two typefaces are served from this site instead of a third party. Where that host is blocked a page used to sit blank for about fourteen seconds.
• SiteThe practice page no longer downloads the 1.2 MB explanation file until you start a session, and a site update no longer makes your device re-download the 3D body model and its viewer.
• SiteLight-mode secondary text now meets the WCAG AA contrast floor, focus rings are back on text inputs, and decorative icons are hidden from screen readers.
• OchemTools, Practice and Mastery now render their content without JavaScript, and the course is described as 62 topics everywhere instead of three different counts.

Layout pass 13 September 2026

• SiteThe "Clay" redesign: soft shadows, a course-tinted opener on every page, and progress you can see moving (the XP chip, level-up toast, bars filling on arrival).
• SiteOne page width across both courses, and shorter interface copy throughout.
• NREMTThe hub asks what you want to do instead of listing everything; the phone "More" sheet is hidden at desktop widths.
• OchemThe notes are a textbook with a contents rail; the course reads as a path; Mastery shows its two long lists side by side; practice modes with nothing in them were removed.

Tools, offline, and the checks that keep it honest 13 September 2026

• OchemSeven interactive tools with quizzes you have to ask for: arrow pusher, resonance explorer, 3D viewer, conformation lab, reaction predictor, acid/base comparator, spectroscopy lab. A molecule carries between tools, and the arrows say what they are.
• NREMTHeart sounds in the sound trainer, with an audio path that survives offline. Flow diagrams and skill sheets became drills rather than documents.
• SiteA real page when the URL is wrong or the network is gone; a link preview on every page; the sitemap is generated; a skip link on every page; answer feedback is announced to screen readers; the OS reduce-motion setting is respected site-wide.
• SiteProgress export and restore, and an analytics opt-out, on the privacy page. The question bank ships as two files so a question shows up sooner.
• SiteTests for the scoring engines and the tool content run on every change.

Study assistant and the ochem textbook 12 September 2026

• SiteA study assistant on every page of both courses. It answers by quoting the course's own material, and can optionally ask an AI model to write from those passages; it says why when it can't answer, and caches answers so a repeated question costs nothing.
• OchemEvery term's first appearance audited across all 62 sections; the textbook is searchable by its words, not just its section names; the periodic table is carried into the textbook.
• SiteOne design system instead of two drifting copies; a chime when an answer is right.

Earlier history is in the commit log.