Study Guides

Chemistry
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	Periodic Table
	Essential Vitamins
	Omnivore’s Dilemma
	Azodicarbonamide
	COVID-19 Situation in the US
	DEET Insect Repellent Important safety information about the use of insect repellents.

Desktop Applications
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	Creative Commons
	Whiteboard Fi
	OBS Studio Free and open source software for video recording and live streaming.
	LibreOffice LibreOffice is a powerful and free office suite used by millions of people around the world.
	Gimp
	OEIS TeX Math Symbols

Django
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	Weather Forecast Santa Rosa
	Local Web Server With Python Spin up a local Python Web server from any directory.

Drupal
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	Installing a Drupal 9 Local Development Environment Notes on command line setup of a new Drupal 9 site using Homebrew, ddev, Docker, and git.
	Useful Drupal 7 Themes A small collection of free and responsive Drupal 7 themes.

Ecology (from Greek: οἶκος, “house” and -λογία, “study of”) is a branch of biology. Topics include biodiversity and populations of living organisms, dynamics of ecosystems, and the flux of energy and matter through an environment.

	Climate Clock Adding the metric of time to the global warming conversation
	Global Warming In recent decades, the average global temperature has increased at the fastest rate in recorded history. Climate measurements show this trend accelerating, with all but one of the 16 hottest years in NASA’s 134-year record having occurred since 2000 CE.
	The Embarcadero Freeway The Embarcadero Freeway is widely considered one of the most glaring examples of corruption in San Francisco's history. For 32 years, the concrete monstrosity blocked the view of the bay. While all but those who profited from it's construction roundly hated the project, it took an earthquake to break it down.
	Weather Weather is what happens to us. We feel it now. It can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season.Climate is the average of all weather patterns measured over longer terms of time and space. Denialism are the delusions about climate as promoted at Fox Fools and some other propaganda-manufacturing, for-profit corporations.
	Head Lice Important information on identifying and removing head lice.
	Bear Safety Important safety information about hiking and camping in bear country.
	Emergency Preparation Preparing for earthquakes, PG&E fires, and other emergencies.
	Air Quality and Smoke Days During the 2017 California PG&E fires, parents and teachers were subjected to an onslaught of misinformation by school administrators eager to maximize ADA (Average Daily Attendance). This post was originally written to provide families with more reliable information about the actual health risks of breathing in smoke. Years later the information remains just as relevant and accurate, mainly because human lungs evolve far slower than the every-shifting political winds and popular prejudices.

English
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	Learn to Type Learn to type correctly using this simple online game.
	Writing a Persuasive Letter
	Writing an Outline

Geology
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The Home Planet The Earth is our home, and we are a part of the Earth. We rely upon the Earth for our very existence. The Earth’s gifts feed us, provide shelter, and all that we need to survive and thrive. Change Is The Only Constant The Earth is dynamic. It is always changing. Even small changes can have profound influences on humanity and civilization. Understanding the Earth’s systems and how they interact is vital for our survival and wellbeing.

	Formation of Planet Earth Our Milky Way galaxy came together nearly 14 billion years ago when enormous clouds of gas and dust coalesced under the force of gravity. Over time, two structures emerged: first, a vast spherical “halo,” and later, a dense, bright disk. Billions of years after that, our own solar system spun into being inside this disk, so that when we look out at night, we see the Milky Way.
	Layers of Planet Earth The Earth is made of many layers. We live on the outer layer, a thin layer of rock and water floating on an ocean of molten rocks and metals.
	Change and Plate Tectonics
	Fire and the Earth Volcanoes have existed for a long time on Earth, and they deserve our greatest respect. They may have caused major planetary disasters, such as the Permian Mass Extinction about 250 million years ago, which may have been the greatest mass extinction on Earth.
	Pele: Goddess of Fire Pele, the Hawaiian Goddess of Fire---like the volcanos she represents---deserves our greatest respect. Hew beauty is awe-inspiring, her moods fiery, and her fury immense.
	Types of Rocks
	Experiment: Growing Salt Crystals Create a supersaturated solution. As the solution becomes unstable, salt crystals will form.
	Crystals Crystals are the outer form of a mineral's inner order. Nearly every piece of rock on Earth is made of minerals, each of which has a precise arrangement of atoms.
	Identifying Rocks To identify a rock, think like a geologist and examine its physical characteristics for clues.
	Fossils
	Minerals and Life We are a part of the Earth, a piece of the whole. Just as our terrestrial planet is made of specific minerals, we are made of the same minerals. Our bodies need many essential minerals to remain healthy. A well-balanced diet can provide all the minerals we need.
	Deep Ocean Vents
	Pale Blue Dot

History
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	Rappler
	Understanding China’s Economy and US Competition Louis-Vincent Gave of Gavekal discusses China's economic growth, its focus on education, and the global implications of its economic and political policies.
	Bertrand Russell’s Last Message This statement on the Middle East was dated 31 Jan 1970, and was read to an International Conference of Parliamentarians meeting in Cairo on February 3 Feb 1970, the day after Bertrand Russell’s death. His message remains just as relevant today as it was then.
	Address to the Western World The Address to the Western World is a powerful message given by the Hau de no sau nee (or traditional Six Nations Council at Onondaga) also called the Iroquois Confederacy, to the non-governmental organizations (NGOs) of the United Nations in Geneva, Switzerland in September, 1977.
	Short Outline of Chinese Civilization No one knows for sure how old Chinese civilization is. We do know that it’s one of the oldest civilizations on Earth, and that it is the only one to have existed unbroken from it's earliest beginning into modern times. Legends claim that the first rulers in China were the Xia Dynasty, from around 2100 to 1600 BCE, and that Yu was the first emperor.
	US Fighters in Manchuria Little known facts about US involvement in the Pacific War prior to the Japanese attack on Pearl Harbor.
	The Christmas Truce of 1914
	Live Without Principle Let us consider the way in which we spend our lives...

Hugo
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	Accessing Remote Data in JSON Format These public servants [should] work for the people.
	How to Create a Recommended Reading Function How to display a list of data items based on matching taxonomy terms. The technique is similar to a "Related Posts" function, but here we create a collection of data records instead of content pages.
	How to Use Range, Where and Sort in Hugo
	Am I Viewing Localhost?
	Default Taxonomy Template in Hugo How to create a default taxonomy template in Hugo.
	Default Taxonomy Template in Hugo How to create a default taxonomy template in Hugo.
	Using Scratch to Increment a Counter in a Range Scratch was originally added to Hugo to get around a limitation of Go templates. Due to advances in Go Templates, Scratch is no longer needed in most situations, but it still works.
	HTML5 Charts in Hugo Thanks to the good work of Shen Yu and a global community of hackers, it is now easy to add fancy charts to Hugo Websites. Here are my first experiments.
	HTML5 Charts in Hugo Thanks to the good work of Shen Yu and a global community of hackers, it is now easy to add fancy charts to Hugo Websites. Here are my first experiments.
	Directory Listings in Hugo How to create a list of files from a directory in Hugo.
	How to Generate a Random Value in Hugo How to create a list of files from a directory in Hugo.
	List Related Content How to create a list of files from a directory in Hugo.
	Working With Taxonomy Templates in Hugo

Javascript
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	Self-Driving Car – No Libraries A fantastic introduction to Javascript programing, including many important concepts and examples from the fields of math, physics and computer science.
	Rafael Animating the Web.
	Random Number Generator Example Javascipt code for a random number generator.

Mathematics 6
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	Sixth Grade Topics An overview of topics for a complete sixth grade mathematics program.
	Equations
	Decimal System
	Squares and Square Roots A headlong plunge into the mighty story of perfect squares and their roots.
	Area in the Coordinate Plane Finding the area of polygons defined by linear equations.
	Danish Hearts
	Metric Measurements
	Metric to US Measurement Conversions
	Prime Numbers
	Division Long division is useful when a problem is too large or complicated to solve another way. Long division usually takes more time, but it always work.
	Exponents Exponentially advanced multiplication, and its inverses.
	Functions All about relations, functions and sequences.
	Measurements Measure twice, cut once.
	Percents Percent means "out of one hundred".
	Ratios A ratio compares two or more values.
	What Is Mathematics?
	Metric Multipliers
	Islamic Golden Age
	Islamic Mosaic Art
	Prime Numbers
	Subtracting Integers
	The Coordinate Plane
	Hexagons
	Glossary of Mathematics Terms Mathematical terms and definitions.

Mathematics 7
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	Equations
	Decimal System
	Squares and Square Roots A headlong plunge into the mighty story of perfect squares and their roots.
	Area in the Coordinate Plane Finding the area of polygons defined by linear equations.
	Metric Measurements
	Metric to US Measurement Conversions
	Multiplying and Dividing Monomials
	Prime Numbers
	Pythagorean Theorem The Pythagorean Theorem is considered one of the most famous mathematical statements, and the fourth most beautiful of all equations.
	Division Long division is useful when a problem is too large or complicated to solve another way. Long division usually takes more time, but it always work.
	Exponents Exponentially advanced multiplication, and its inverses.
	Measurements Measure twice, cut once.
	Percents Percent means "out of one hundred".
	Ratios A ratio compares two or more values.
	What Is Mathematics?
	Metric Multipliers
	Algebra Glossary A monumental and ever-expanding list of vital terms with their definitions.
	7-2-7. One-Step Equations With Rational Numbers
	Comparing, Ordering, Adding, Subtracting Rational Numbers
	Hexagons
	Glossary of Mathematics Terms Mathematical terms and definitions.

Mathematics 8
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	Eighth Grade Topics
	What Is Mathematics?
	Decimal System
	Data Visualization All about how to read visual data.
	Exponents Exponentially advanced multiplication, and its inverses.
	Functions All about relations, functions and sequences.
	Flipping Digits These digit flipping challenges are tough at first, but with practice you can become a pro.
	Glossary – Mathematics Mathematical terms and definitions.
	Glossary – Algebra A monumental and ever-expanding list of vital terms with their definitions.
	Parallel and Perpendicular Lines
	Solving Inequalities With Variables on Both Sides
	Metric Multipliers
	Phi
	PI
	Slope Ye awesome overview of slopes, mountains, and steep ravines..
	Squares and Square Roots A headlong plunge into the mighty story of perfect squares and their roots.
	Systems of Linear Equations Solving systems of linear equations.
	Area in the Coordinate Plane Finding the area of polygons defined by linear equations.
	Metric Measurements
	Metric to US Measurement Conversions
	Prime Numbers
	Pythagorean Theorem The Pythagorean Theorem is considered one of the most famous mathematical statements, and the fourth most beautiful of all equations.
	Absolute Value Absolutely the best guide you are likely to find covering the essentials of absolute values and their equations.
	Equations An overview of essential information needed for working with linear equations
	Inequalities Overview An utterly unequaled compendium of factoids highlighting the finer points of unequal solutions.
	Inequalities With Multiplication and Division
	Linear Functions
	Measurements Measure twice, cut once.
	Percents Percent means "out of one hundred".
	Point-Slope Form
	Ratios A ratio compares two or more values.
	Review 1: Ready to to On?
	Solving Absolute Value Inequalities
	Solving Compound Inequalities

Physics 10
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	Electromagnetism
	Electromagnetism
	Discoverers of Electromagnetic Energy
	What Is Sound?
	Glass Harp
	Speed of Light
	Light Refraction
	Lighting
	Microwaves
	Sound Propagation Sound is all about vibrations. To make a sound, there needs to be a source---something that vibrates---whether it's a musical instrument, the larynx (voice box) of a person, or the movement of Tectonic Plates...
	Electric Switch
	Doppler Effect
	Single and Parallel Circuits
	Electric Motor
	Static Electricity
	Music
	Magnetism
	Quantum Levitation

Physics 12
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The study of the physical properties of sound, light, heat, gravity, fluid dynamics, magnetism and electricity.

Additive Light

Our eyes are sensitive to a very narrow band of frequencies within the the electromagnetic spectrum. This narrow band is referred to as the visible light spectrum.

Physics 6
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The study of the physical properties of sound, light, heat, magnetism and electricity.

	Propagation of Sound G6
	Sources of Sound G6
	Electromagnetism
	Sources of Heat
	Visible Light
	Sound in Water
	Radiometer
	Expansion and Contraction
	Visible Light
	Speed of Light
	Conduction
	Magnetism
	Static Electricity
	Convection
	Solar Oven
	Spectroscope

Physics 7
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The study of the physical properties of sound, light, heat, gravity, fluid dynamics, magnetism and electricity.

	Bicycles
	Levers There are three classes of levers, depending on where the load and effort are located compared to the fulcrum. Each type of lever has its own uses and advantages.
	Pulleys A pulley is collection of one or more wheels over which a rope is looped. The arrangement makes it easier to move and lift heavy objects.
	Bridge Videos
	Bridges
	Electromagnetism
	The Scientific Method
	Origami Mobile How to make a mobile with origami cranes.
	Six Simple Machines Simple machines are devices with no---or very few---moving parts.
	Sound G7
	Glass Harp
	Doppler Effect
	Radiometer
	Speed of Light
	Lighting
	Metric Multipliers
	Physics Jokes

Physics 8
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The study of the physical properties of sound, light, heat, gravity, fluid dynamics, magnetism and electricity.

	Electromagnetism
	Isaac Newton
	Laws of Motion
	Newton’s Cradle
	Rube Goldberg Cartoons
	The Four Fundamental Forces of the Universe
	The Pendulum
	The Scientific Method The scientific method is critical to the development of scientific theories. These theories are then used to try to explain the empirical (experiential, observable, measurable) world.
	Discoverers of Electromagnetic Energy
	What Is Sound?
	Sound in Water
	Speed of Light
	Light Refraction
	Lighting
	Microwaves
	Sound Propagation Sound is all about vibrations. To make a sound, there needs to be a source---something that vibrates---whether it's a musical instrument, the larynx (voice box) of a person, or the movement of Tectonic Plates...
	Electric Switch
	Doppler Effect
	Single and Parallel Circuits
	Electric Motor
	Static Electricity
	Music
	Magnetism
	Quantum Levitation
	Quantum Levitation
	Metric Multipliers
	Physics Jokes

	My Heart Is Breaking This article written from the perspective of a school psychologist echoes many concerns shared by classroom educators.
	A Future for the World’s Children? As climate and commercial threats intensify, WHO-UNICEF-Lancet Commission presses for radical rethink on child health.

	Converting HTML to PDF on the Command Line Using Google Chrome How to convert HTML TO PDF on the command line using Chromium (Google Crome) as the rendering engine.
	Converting Files in HEIC Format to JPEG Format How to convert those pesky HEIC files into JPEG format.
	Converting Files in HEIC Format to JPEG Format How to convert those pesky HEIC files into JPEG format.
	Rdiff-Backup Script Using rdiff-backup on macOS
	Rdiff-Backup Script Using rdiff-backup on macOS
	Find Command Find command cheatsheet
	Find Command Find command cheatsheet