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What is a chemical?
What is a chemical?
Many people think that a chemical is a man-made (artificial) molecule.
Others say that some chemicals are man-made, while others are natural, but they often don’t have specific definitions.
On top of that, many people feel that “chemicals are bad for you.”
The confusion likely exists because – as surprising as it sounds – until recently there never has been an exact definition of the word.
We can’t do anything in science, or communicate anything that we have learned, without specific and exact definitions. So in science we do have specific definitions for atoms, elements, compounds and molecules.
But although the word “chemical” is widely used, until recently no attempt was made to precisely define it. What we can do is look at scientific papers and see how the word has been used:
A chemical is any substance consisting of matter.
This includes any liquid, solid, or gas.
A chemical is any pure substance (an element) or any mixture (a solution, compound, or gas).
They can either occur naturally or can be created artificially.
What Is Not a Chemical?
If anything made of matter is made up of chemicals, which means that only phenomena that aren’t made of matter are not chemicals: Energy is not a chemical. Light, heat, and sound are not chemicals—nor are thoughts, dreams, gravity, or magnetism.
What Is a Chemical and What Isn’t a Chemical? By Anne Marie Helmenstine, ThoughtCo, 12/7/2019
Surprising, eh? You’re made of chemicals! All trees, plants, and grass are made of chemicals. The Earth, moon, asteroids, and everything we can touch is made of chemicals. A single atom of gold, a sodium ion dissolved in our blood, a molecule of Vitamin C, are all chemicals.
At this point please see Every food we eat is made of nothing but chemicals!
Ore genesis (how ore deposits are created)
Main idea:
In previous units we have learned about metals and gems.
We further learned about ores (rock that contains valuable minerals that can be mined and sold at a profit.)
In this unit we learn several ways that ore deposits were created in the first place.
These processes are called ore genesis. (Not to be confused with the similar-sounding, but completely different, orogenesis.)
Pre-loading vocabulary
deposit (verb) – to put something down (e.g. money in a bank, or particles in a riverbed)
deposition (noun) – the process of silt and sediment building up in an area.
Here we see a GIF of particles moving through water, and eventually being deposited on the sea floor (deposition.)
Over long periods of time, this deposited material can be chemically cemented together into sedimentary rock. This is term sedimentation.
sedimentation (verb) – the process of particles settling or being deposited.
sedimentary rock (noun) – rock formed from fragments of other rocks or the remains of plants or animals.
element (noun) – Elements are pure substance made from a single type of atom. For all practical purposes, an element is something that cannot be broken down into anything simpler. Examples: Oxygen, Carbon, Hydrogen, Gold, Iron, etc.
Microbial Genomics and the Periodic Table, Lawrence P. Wackett, Anthony G. Dodge and Lynda B. M. Ellis
hydrothermal vent (noun) – An opening on the seafloor that emits hot, mineral-rich solutions.
GIF from gfycat.com
mid-ocean ridge (noun) – underwater mountain range.
National Oceanic and Atmospheric Administration (NOAA), ETOPO1 Global Relief Model,
http://www.virginiaplaces.org/geology/rocksdui4.html
ore (noun) – deposit in the Earth of minerals containing valuable metal.
ore body (noun) – a well-defined mass of ore-bearing rock
from Applied Geochemistry
Advances in Mineral Exploration Techniques, Macheyeki et al.
subduct (verb) – When one tectonic plate hits another, and one of the plates is forced below the other. The subducted plate is the one going deeper into the mantle.
subduction zone (noun) – An area where one tectonic plate slides under another.
Deep versus surface processes
Sometimes we classify ore producing processes as either
supergene – those that occur near the surface.
hypogene – those that occur deep under the Earth’s surface.
Ways that ore deposits form
A National Geographic infographic describes three ways that ore deposits form:
(1) Ore deposits created underwater, within sedimentary rock like shale.
The rock/shale forms from nearby volcanic arc, settles on seafloor in layers. This sediment is rich in minerals that contain lead, silver, zinc.
As layer after layer of sediment build sup, the pressure on lower layers increases. The temp increases. The lower layers then begin to melt.
When sea water seeps in through cracks in the crust, the rocks expel these metals, which form ore bodies. Usually occurs within subduction zones.
(2) Subduction zone ore deposits.
Tectonic plates contain large quantities of water. As a tectonic plate is subducted into the mantle it heats up and releases this water. The resulting fluid travels up to the rocks above the subduction zone.
Combined with significant heat, this fluid-filled environment can create the right conditions for ore deposits to form. Includes Gold and copper.
(3) Hydrothermal vent ore deposits.
Deep sea hydrothermal vents line mid-ocean ridges. These vents spew incredibly hot water, which contains dissolved metals like copper, lead, zinc, and iron.
When this super heated liquid hits cold ocean water, the metals become solid and settle onto the ocean floor. Over time they build up on the seafloor near these vents, creating ore bodies than can be minded.
Looking on a global view, where do these processes occur?
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See Compare and Contrast: Ore Deposition Infographic
Ores from hot water
This text is from the American Museum of Natural History
‘”Driven by heat from bodies of molten rock in the crust, hot water circulates through cracks, dissolving minerals in the rocks through which it passes. As the water moves into cooler rocks, the dissolved minerals precipitate and accumulate in fractures and cavities. Many metallic ore deposits, such as those represented in the samples shown here, form in this way.”
How weathering can produce ore deposits
Here are two examples of how weathering creates ores from Earth Science (Tarbuck, Lutgens, Tasa) This process is called secondary enrichment.
(A) Chemical weathering coupled with downward-percolating water removes undesired materials from decomposing rock.
This leaves the desired elements enriched in the upper zones of the soil.
(B) The second way is basically the reverse of the first. Desirable elements that are found in low concentrations near the surface are removed and carried to lower zones, where they are redeposited and become more concentrated.
Learning Standards
MS-ESS3-1. Construct a scientific explanation based on evidence for how the uneven distributions of Earth’s mineral, energy, and groundwater resources are the result of past and current geoscience processes.
[Clarification Statement: Emphasis is on how these resources are limited and typically non-renewable, and how their distributions are significantly changing as a result of removal by humans. Examples of uneven distributions of resources as a result of past processes include but are not limited to petroleum (locations of the burial of organic marine sediments and subsequent geologic traps), metal ores (locations of past volcanic and hydrothermal activity associated with subduction zones), and soil (locations of active weathering and/or deposition of rock).]
Disciplinary Core Ideas – ESS3.A: Natural Resources
Humans depend on Earth’s land, ocean, atmosphere, and biosphere for many different resources. Minerals, fresh water, and biosphere resources are limited, and many are not renewable or replaceable over human lifetimes. These resources are distributed unevenly around the planet as a result of past geologic processes.
Crosscutting Concepts – Influence of Science, Engineering, and Technology on Society and the Natural World
All human activity draws on natural resources and has both short and long-term consequences, positive as well as negative, for the health of people and the natural environment.
HS-ESS3-2. Evaluate competing design solutions for developing, managing, and utilizing energy and mineral resources based on cost-benefit ratios.
[Clarification Statement: Emphasis is on the conservation, recycling, and reuse of resources (such as minerals and metals) where possible, and on minimizing impacts where it is not. Examples include developing best practices for agricultural soil use, mining (for coal, tar sands, and oil shales), and pumping (for petroleum and natural gas). Science knowledge indicates what can happen in natural systems—not what should happen.]
4-ESS3-1. Obtain and combine information to describe that energy and fuels are derived from natural resources and their uses affect the environment.
HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems
[Clarification Statement: Examples of environmental effects could include loss of habitat due to dams, loss of habitat due to surface mining, and air pollution from burning of fossil fuels.]
Ores and ore deposits
What are ores?
Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.
The societal importance of ores
Mark Hoggard writes
Copper, lead, and zinc form three of the four base metals (the other being nickel) and are heavily relied upon by modern society. Copper’s high electrical conductivity means that it is utilised in virtually all electronics and wiring. Lead is used in photovoltaic cells, high-voltage power cables, batteries, and super capacitors. Zinc is used in batteries and paints, but also in agricultural fertilisers and fungicides since it is a limiting micronutrient in many of the world’s crop soils.
from Treasure maps, sustainable development, and the billion-year stability of cratonic lithosphere
Many minerals are used in our smartphones, tablets, computers, and all home electronics:
Some thoughts to ponder!
How many pounds of minerals are required by the average person in a year?
How large is a lifetime supply of minerals for the average person?
How do we find ores? Prospecting
Classically, people would walk around and dig into the ground. They’d examine the soil and rocks to see if there were any significant amounts of important minerals, metals, gems, etc. This was called prospecting. Even 2000 years ago people in many civilizations had simple ways of doing this.
By the time of the industrial revolution (1780s to 1830s) most easy surface deposits had been used up. From here onwards, corporations needed to employ many scientifically literate explorers to systematically dig and drill into many places all across the globe.
Chemists and geologists would carefully examine samples, determining if there was enough ore to make it economically worthwhile to mine that area.
To some extent this also happens today. Here we see geologists from the USGS and the New Mexico Bureau of Geology and Mineral Resources examining a carbonatite dike in the Lemitar Mountains, New Mexico.
Geologists examining a carbonatite dike, USGS
However, that kind of prospecting is less common today. We have to come to rely on various high tech strategies that let us find ore deposits that otherwise are more difficult to find.
There are now ways of Finding ores in underwater ocean deposits
Marine self-potential survey for exploring seafloor hydrothermal ore deposits, Yoshifumi Kawada & Takafumi Kasaya
We have remote sensing from airplanes flying overhead. Airplanes carry sensors which look at the ground with in visible and infrared light imaging spectrometers.
For instance, APEX is an airborne imaging spectrometer developed by a Swiss-Belgian consortium on behalf of ESA
APEX consortium, apex-esa.org
In our generation we use explore Earth for minerals deposits using remote multispectral imaging; these sensors are on satellites in Earth orbit.
Read about Mineral Exploration of Earth from Satellites in Space.
One such example is Terra (EOS AM-1.) This is a multi-national, NASA scientific research satellite. And below we see the Copernicus Sentinel-2 satellite from the ESA (European Space Agency.)
Image from Astrium GmbH. https://www.esa.int/Applications/Observing_the_Earth/Spotlight_on_Sentinel-2
Mining: How do we remove mineral from the Earth?
Prospecting is all about finding the right places to find ores. The next challenge is mining, getting these materials out of the Earth, grinding them up, and then transporting them off to factories.
In some locations there are great, open wounds on the fact of the Earth, where we see giant machines slowly digging into the Earth, in ever-wider and ever-deeper areas. Over a period of years tremendous amounts of materials ate pulled out of the Earth.
The advantage is that we obtain the minerals we need or want for our society.
The disadvantages are that badly damages the local environment and ecology. This often has deleterious side effects for people who locally. This is why we need people educated in geology, the scientific method, philosophy and ethics to be a part of this process.
Refining the ores
Next is refining (separating the metal from the other materials that it is mixed in)
Here are metals once they are refined, but before they are made into useful products.
Finally one will form the metal into an industrial product.
There’s quite a separate process, of course, for removing gemstones from the ores that they are found in.
Gem-containing ore are valuable and highly sought after:
The five cardinal gems of antiquity. Clockwise from top: Sapphire, Ruby, Emerald, Amethyst, Diamond. (Cardinal gems, Wikimedia Commons)
Examples of ores
Oxide mineral ores
https://openpress.usask.ca/physicalgeology/chapter/5-3-mineral-groups-2/
and
.
How are ore deposits created?
Weathering creates many important mineral deposits by concentrating minor amounts of metals that are scattered through unweathered rock into economically valuable concentrations.
Called secondary enrichment:
(A) In one situation, chemical weathering coupled with downward-percolating water removes undesired materials from decomposing rock, leaving the desired elements enriched in the upper zones of the soil.
(B) The second way is basically the reverse of the first. That is, the desirable elements that are found in low concentrations near the surface are removed and carried to lower zones, where they are redeposited and become more concentrated.
Ores from hot water, American Museum of Natural History
Some ore deposits are formed through hydrothermal/plutonic intrusions.
Some Caribbean have such deposits – Jamaica and bauxite
Some ore deposits in western states (copper, iron) may have been originally formed in deep sea hydrothermal vents that were scraped or accreted from the edges of various terranes that make up those states.
External reading
Evolutionary and Revolutionary Technologies for Mining, Technologies in Exploration, Mining, and Processing
Learning Standards
TBA
Glaciers
Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite).
BEAR GLACIER, KENAI FJORDS NATIONAL PARK, ALASKA. US NPS PHOTO
The mineral ice is the crystalline form of water (H2O).
Glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice.
Each snow flake is a single, six-sided (hexagonal) crystal with a central core and six projecting arms.
FROM POLARTREC.COM
The metamorphism process is driven by the weight of overlying snow.
During metamorphism, thousands of individual snowflakes recrystallize into much larger and denser individual ice crystals.
Some of the largest ice crystals observed at Alaska’s Mendenhall Glacier are nearly one foot in length.
(USGS)
Use PowerPoint presentation from Earth Science (Tarbuck, Lutgen, Tasa) It covers the topics mentioned below.
Types of glaciers
Valley Glaciers
Ice sheets
Where glaciers exist today
Cover most of Iceland, most of Antarctica
some other locations
How glaciers move
(from Earth Science Tarbuck, Lutgens)
The movement of glaciers is referred to as flow, and it happens in two ways.
1. Plastic flow—involves movement within the ice
2. Basal slip—slipping and sliding downward due to gravity
The glacial budget
The balance, or lack of balance, between accumulation of ice at the upper end of a glacier – and the loss, or wastage, at the lower end of the glacier.
Calving
tba
Glacial erosion
Many landscapes were changed by the widespread glaciers of the recent ice age.
• Plucking—lifting of rock blocks
– Rock flour (pulverized rock)
– Striations (grooves in the bedrock)
How glaciers shape the land
As glaciers move they can break up the ground underneath them. They then pluck, or pick up, big chunks of rock, and began to carry them downhill.
Glaciers are responsible for a variety of erosional landscape features, such as glacial troughs, hanging valleys, cirques, arêtes, and horns.
Glaciated valleys – A glacial trough is a U-shaped valley that was once V-shaped but was deepen by a glacier.
A cirque is a bowl-shaped depression at the head of a glacial valley.
Arêtes and Horns
Snaking, sharp-edged ridges called arêtes and sharp pyramid-like peaks called horns project above mountain landscapes.
Types of Glacial Drift
• Glacial drift applies to all sediments of glacial origin, no matter how, where, or in what form they were deposited.
1. Till is material deposited directly by the glacier.
2. Stratified drift is sediment laid down by glacial meltwater.
Depositional features
Glaciers are responsible for a variety of depositional features, including
Moraines—layers or ridges of till
outwash plains—sloping plains consisting of deposits from meltwater streams in front of the margin of an ice sheet
kettles—depressions created when a block of ice becomes lodged in glacial deposits and subsequently melts.
drumlins—streamlined, asymmetrical hills composed of glacial dirt.
eskers—ridges composed largely of sand and gravel deposited by a stream flowing beneath a glacier near its terminus.
.
Antarctica
Antarctica is Earth’s southernmost continent
It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere. It lies almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean.
Here we see Antarctica on the left. For comparison we shop the Earth’s geographic north pole on the right:
NASA Scientific Visualization Studio. https://svs.gsfc.nasa.gov/3944
At 14,200,000 square kilometres (5,500,000 square miles), it is the fifth-largest continent and nearly twice the size of Australia.
It is by far the least populated continent, with around 5,000 people in the summer and only around 1,000 in the winter.
About 98% of Antarctica is covered by ice that averages 1.9 km (1.2 mi; 6,200 feet) in thickness,
It is the coldest, driest, and windiest continent. It has the highest average elevation of all the continents.
Most of Antarctica is a polar desert, with annual precipitation of 200 mm (7.9 in) along the coast and far less inland; yet 80% of the world’s freshwater reserves are stored there, enough to raise global sea levels by about 60 metres (200 feet) if all of it were to melt.
Organisms native to Antarctica include many types of algae, bacteria, fungi, plants, protista, and certain animals, such as mites, nematodes, penguins, seals and tardigrades. Vegetation, where it occurs, is tundra.
Under the ice cap
Here’s What Antarctica Looks Like Under All The Ice Colin Schultz, Smithsonian Magazine, 6/5/2013
NASA’s IceBridge Mission Contributes to New Map of Antarctica, NASA
video: The Bedrock Beneath Antarctica – NASA, NASA Goddard
Possible mantle plume under the continent
Antarctic mantle plume: the news is being sensationalized
Let’s All Calm Down and Make Sense of That Antarctic Mantle Plume
“The possibility that a deep mantle plume manifests Pliocene and Quaternary volcanism and potential elevated heat flux in West Antarctica has been studied for more than 30 years. Recent seismic images support the plume hypothesis as the cause of Marie Byrd Land (MBL) volcanism and geophysical structure”
Influence of a West Antarctic mantle plume on ice sheet basal conditions, Helene Seroussi, Erik R. Ivins, Douglas A. Wiens, Johannes Bondzio, Journal of Geophysical Research: Solid Earth, Vol 122(9) 2017
NSF/Zina Deretsky
History
Antarctica was the last region on Earth to be discovered, likely unseen until 1820 when the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev sighted the Fimbul ice shelf.
The continent remained largely neglected for the rest of the 19th century because of its harsh environment, lack of easily accessible resources, and isolation.
In January 1840, land at Antarctica was discovered for the first time, almost simultaneously, by the United States Exploring Expedition, under Lieut; Charles Wilkes; and a separate French expedition under Jules Dumont d’Urville. The latter made a temporary landing. The Wilkes expedition—though it did not make a landing—remained long enough in the region to survey and map some 800 miles of the continent. The first confirmed landing was by a team of Norwegians in 1895.
Antarctica is governed by parties to the Antarctic Treaty System. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then. The treaty prohibits military activities, mineral mining, nuclear explosions and nuclear waste disposal. It supports scientific research and protects the continent’s ecology.
Between 1,000 and 5,000 people from many countries reside at research stations scattered across the continent.
Did Antarctica remain entirely unvisited by humans until the early 19th century?
What is Earth Science? Why study it?
What is earth science?
The earth sciences include studies of the atmosphere, hydrosphere, cryosphere, and the relations among them and with the biosphere. Study of the earth sciences directly addresses several issues of great societal concern, including but not limited to natural disasters such as devastating hurricanes, and the global effects of a changing climate.
The earth sciences connect the world of science with all students’ daily experiences: The weather is a never-ending “science experiment” in progress outside classroom windows. Teachers with sound training in the earth science basics have endlessly interesting and relevant material to draw upon that connects science with the students’ past experiences and daily lives.
Earth science helps students see how all of the sciences are related because to study the Earth, scientists and students must use the knowledge and techniques of several disciplines, including but not limited to physics, chemistry, mathematics, and computer science. Learning about the Earth helps students realize that their world is made of interconnected, dynamic systems.
In addition, the earth sciences, and especially weather, connect science with the world students come to know through the news media, especially television. Surveys over the past several years have shown that television is the primary source of news for the majority of Americans. With the exception of weather, most of the science that television news presents is about health and medicine. In fact, television weathercasters are likely to be the only representatives of science students and their parents regularly see….
The value of earth science classes goes beyond the intellectual benefits. Over the years, various reports have testified to the life-saving value of earth science education. One of the most dramatic of these came from the 26 December 2004 tsunami that devastated coastal areas around the Indian Ocean, killing as many as 300,000 people. A British schoolgirl, who had studied tsunamis in school, recognized precursors of the tsunami that was about to hit the beach in Thailand she was visiting. The schoolgirl persuaded her mother to shout a warning, which is credited with saving 100 people on the beach.
In the United States, students in earth science classes learn how to react when endangered by tornadoes, hurricanes, floods, lightning, and other hazards….
Students who study the earth sciences will better understand the value of the Earth’s resources, how its components are related, and the need to care for the Earth. Men and women who possess a basic understanding of the Earth will be able to participate as informed citizens in policy debates, such as about climate change. Society will be the ultimate beneficiary as its citizens become more aware of the science that explains weather, earth’s water, the oceans, and the Earth itself.
– From Earth Science Education, Adopted by American Meteorological Society Council, 29 January 2006. Bull. Amer. Met. Soc., 87
Science, ethics, and morality
Science is not a position. It is not a person. It is not a group. It has no social or political beliefs. rather, science is a method that allows us to test claims about the physical world in which we live. Science allows us to investigate the nature of reality, and helps reveal our place in the universe.
“In science we approach claims skeptically. That doesn’t mean that that we don’t believe anything. Rather, to be skeptical means we don’t accept a claim unless we are given compelling evidence. Skepticism is a provisional approach to claims.”
– Michael Shermer
As amazing and powerful as science is, however, it has a very specific domain: It only reveals phenomenon in the natural world. Science tells us nothing about right and wrong, good and evil. In other words, science is not about ethics or morality any more than mathematics is. Mathematics is amazing and powerful, and and we combine math with science we can engineer buildings, bridges, skyscrapers, spacecraft. and supercomputers. But math doesn’t say anything about right or wrong.
As such, we should we dubious when we hear claims that indicates science proves or disproves someone’s moral or social beliefs.
A great resource, “Understanding Science,” by the UC Museum of Paleontology of the University of California at Berkeley, clarifies:
Science is powerful. It has generated the knowledge that allows us to call a friend halfway around the world with a cell phone, vaccinate a baby against polio, build a skyscraper, and drive a car. [Yet] science has definite limits.
Science doesn’t make moral judgments
When is euthanasia the right thing to do? What universal rights should humans have? Should other animals have rights? … ultimately, individual people must make moral judgments. Science helps us describe how the world is, but it cannot make any judgments about whether that state of affairs is right, wrong, good, or bad.
Science doesn’t make aesthetic judgments
Science can reveal the frequency of a G-flat and how our eyes relay information about color to our brains, but science cannot tell us whether a Beethoven symphony, a Kabuki performance, or a Jackson Pollock painting is beautiful or dreadful. Individuals make those decisions for themselves based on their own aesthetic criteria.
Science doesn’t tell you how to use scientific knowledge
… Science, for example, can tell you how to recombine DNA in new ways, but it doesn’t specify whether you should use that knowledge to correct a genetic disease, develop a bruise-resistant apple, or construct a new bacterium.
Science has limits: A few things that science does not do
There is no scientific experiment that one can possibility make that will tell us right from wrong, good from evil.
There is no peer-reviewed scientific evidence that proves that one should love one’s brother or that one should be racist.
There is no peer-reviewed scientific evidence that proves that we should either “share our bread with the hungry and bring the homeless into our house” (Isaiah 58:7) or that we should ignore or shun the hungry and the homeless.
There is no peer-reviewed scientific evidence that proves that we should judge people not “by the color of their skin but by the content of their character.” (Martin Luther King Jr.) or whether we should judge people from external appearances.
There is no experimental morality meter. Science doesn’t measure “goodness.”
A classic illustration of the intersection of ethics and science can be seen in the classic painting, An Experiment on a Bird in the Air Pump. It is by Joseph Wright, 1768. Science allows us to investigate air pressure, and the nature of vacuums. Science allows us to understand how varying air pressure affects the health of people and animals. But no scientific experiment can tell us whether or not it is ethical to perform experiments on animals, or if so, under what circumstances.
Scientists on science and morality
I do not believe that a moral philosophy can ever be founded on a scientific basis. … The valuation of life and all its nobler expressions can only come out of the soul’s yearning toward its own destiny. Every attempt to reduce ethics to scientific formulas must fail. Of that I am perfectly convinced.
Albert Einstein, ‘Science and God: A Dialogue’, Forum and Century (June 1930), 83, 374
Misuse of science: Examples
TBA
Attacks on Science
Lunar precession (the moon’s wobble)
As seen from here on Earth, our moon has a number of types of wobble. Here we will look at each of them.
Lunar Libration
Over the course of a month, we see a bit more than half of the moon’s surface from here on Earth. This apparent motion is called lunar libration.
About 59% of the Moon’s surface is visible, thanks to
Lunar libration in latitude
due to the Moon’s axis being slightly inclined relative to the Earth’s axis. From our angle we can at one time peek over the north pole of the Moon, and then later in the lunar month we peek over the south pole. Over the entire four week cycle it gives the the effect of the Moon slowly “nodding its head yes.”
Diurnal (daily) libration
due to the observer first viewing from the western edge of the Earth as the Moon is rising, and then later from up to four thousand miles away to the east as the Moon is setting. This is due to the rotation of the Earth. The difference in perspective between the rising and setting of the Moon appears as a slight turning of the Moon first to west and then to east, as though “shaking its head no.”
Libration of longitude
an effect of the Moon’s varying rate of travel along its slightly elliptical orbit around the Earth. The Moon travels faster when it is at its closest to Earth, and its slowest when it is farthest away. Its rotation on its own axis is more regular, the difference appearing again as a slight east-west “no” oscillation.
— Skywise Unlimited, Astronomy 101
Lunar libration with phase
Why is there lunar libration? See this GIF from space.fm.
Lunar Axial precession
The rotational axis of the Moon undergoes precession.
What is precession? It is a change in the orientation of the rotational axis of a rotating body.
If the axis of rotation of a body is itself rotating about a second axis then that body is said to be precessing about the second axis.
Since the Moon’s axial tilt is only 1.5° with respect to the ecliptic (the plane of Earth’s orbit around the Sun), this effect is small.
Once every 18.6 years the lunar north pole describes a small circle around a point in the constellation Draco.
Correspondingly, the lunar south pole describes a small circle around a point in the constellation Dorado.
Lunar Apsidal precession
Wikipedia, Precessing Kepler orbit 280frames e0.6 smaller.gif
The major axis of the Moon’s elliptic orbit (the line of the apsides from perigee to apogee) precesses eastward by 360° in approximately 8.85 years.
This is the reason that an anomalistic month (the period the Moon moves from the perigee to the apogee and to the perigee again) is longer than the sidereal month (the period the Moon takes to complete one orbit with respect to the fixed stars).
Here we see the moon’s orbit apsidal precession: Lunar Apsidal motion
Wikimedia, Moon apsidal precession.png
Nodal precession
Precession of the plane of the Moon’s orbit.
The period = the time it takes the ascending node to move through 360° relative to the vernal equinox (autumnal equinox in Southern Hemisphere).
The period is about 18.6 years.
The direction of motion is westward, i.e. in the direction opposite to the Earth’s orbit around the Sun, if seen from the celestial north.
Investigate: Is this animation in the right section?
and
This is the reason that a draconic month or nodal period (the period the Moon takes to return to the same node in its orbit) is shorter than the sidereal month.
After one nodal precession period, the number of draconic months exceeds the number of sidereal months by exactly one. This period is about 6,793 days (18.60 years).
Environmental social justice
Our family has been concerned about environmental social justice, and keeping science free from political interference, for generations. Here we’re at the Boston March for Science.
Developing a learning mindset
Sometimes it’s hard for people to learn new things, especially on topics that one has some emotional investment in. Teachers and scientists have discovered that, often, when people are presented with new data which should change their minds – the mere presence of new information causes discussion to backfire.
Showing someone that a tightly held belief is incorrect sometimes makes people double-down on their belief, and hold onto it even more. This phenomenon has a name – the backfire effect.
We see this on topics like evolution. It also comes up for science about environmental social justice. Some people find it difficult to believe that our civilization can pollute the planet so much that it physically change’s the world’s climate. Others find it hard to believe that pollution and industrial waste is adversely affecting poor communities.
You’re Not Going to Believe What I’m Going To Tell You
The Backfire Effect: The Psychology of Why It Is Hard to Change Our Minds
Backfire effect, RationalWiki
What is environmental justice?
A brief description
Environmental justice is the idea that every person has the right to a healthy environment. It also means that every person has the right to be involved in decisions about what happens to that environment.
The environmental justice movement started in the 1970s. A woman named Lois Gibbs was one of the movement’s leaders early on. In 1978 Gibbs led protests against the contamination of a neighborhood known as “Love Canal” in upstate New York… the protests mattered. They made the news. More people started to care about the environmental justice movement. Groups put out new studies. The studies proved minorities and the communities they lived in were dealing with dangerous wastes more than other communities. One such study came out in 1987. It was called “Toxic Waste and Race in the United States.”
from – What is environmental justice? Gale, Cengage Learning, Newsela staff, 11/16/2017
John Francis, PlanetWalker
Air pollution and smog
Air pollution is the presence of substances in the air that are harmful to our health, or to the health of other living beings, such as animals or food crops. Air pollution may cause diseases, allergies and even death.
Both human activity and natural processes can generate air pollution.
In this resource we look at human-causes forms of air pollution such as acid rain and smog: air pollution.
Why the fight for clean air is a social justice issue
Disparities in the Impact of Air Pollution
Pollution Is a Racial Justice Issue. Let’s Fight it that Way
Global warming
Having some greenhouse gases in the atmosphere in perfectly natural, and even essential for life as we know it. But human industrial activity has released vast amounts of additional greenhouse gases, at an accelerating rate, for the past three centuries. This has increased the greenhouse effect, leading to a marked warming of the earth – both our atmosphere and ocean.
What are greenhouse gases and how do they lead to global warming?
Global warming has not stopped – Addressing a misunderstanding
Global warming Industry knew of climate change – They knew
Global warming isn’t natural, and here’s how we know – Go through every possibility
Global warming is leading to a rise in sea levels. This is already beginning to affect coastal cities around the world, and the effect will eventually become significantly worse. Rich people can afford to move to wherever they like, but most middle class and poor people will experience tremendous problems. Citizens need to know what could happen, what is happening, and wat possible steps we can take to avoid dramatic damage.
If all land ice melted how would coastlines change
New York City: Protecting it from rising sea levels
Boston MA: Proposals to protect the greater Boston area
New Orleans, Louisiana – Protecting from rising sea levels
Ozone layer
About 20 to 30 km up, our atmosphere contains ozone gas. It’s important because it stops much of the sun’s ultra-violet (UV) rays. As such, only a small percent of UV light reaches the surface. But human production of certain chemicals – such as CFCs – have damaged the ozone layer, allowing more UV light through, which can cause an increase in skin cancer as well as damage to crops. We learn about this here – The Ozone layer and CFCs
Clean water
“Many consider it self-evident that everyone should have access to safe, clean drinking water. In fact, the United Nations has even declared access to clean water a human right… Unfortunately, despite the overall wealth and prosperity of America, access to safe drinking water is not a guarantee.
… as many as 63 million Americans were exposed to unsafe drinking water between 2007 and 2017. Unclean water can cause serious and costly health issues, and studies have found that poor and minority communities across the U.S. are disproportionately affected by polluted waters. Advocates refer to the imbalance of environmental risk and exposure to pollution by poor and minority communities as environmental injustice. …Once again, poor communities of color are disproportionately bearing the brunt of environmental injustice.”
Excerpted from Clean Water and the Environmental Justice Movement
Clean water: Pouring a foundation for social justice
Social Justice Equals Clean Water
Clean Water and Environmental Justice in California
WE ACT For Environmental Justice
Watered Down Justice (PDF report) NRDC
Flint Michigan Water Crisis
One of the worst abuses related to providing clean water was the Flint, Michigan water crisis (2014 to 2019.)
In 2014 Flint changed its water source. Officials failed to apply corrosion inhibitors to the new water source. As a result, lead from aging lead pipes leached into the water supply. This led to extremely elevated levels of the heavy metal lead, exposing over 100,000 residents to elevated lead levels.
Read about it here Flint Michigan Water Crisis
Boston, MA and the Charles River
The original Native American name for this river was Quinobequin – “meandering” or “tortuous.” In 1965 the Charles River was so dirty that The Standells wrote a song about it.
That was the same year the Charles River Watershed Association launched the first major effort to improve the quality of the river. It had been polluted by raw sewage and rainwater that flowed from old drainage pipes in Boston Harbor.
The eventual clean-up of the Charles River is one of the great success stories of the environmental justice movement.
Charles, Science in the News, Harvard
A Tale of Two Rivers – The Charles and the Mystic
How we make things better
In 1970, then President Richard Nixon and Congress worked together to establish the Environmental Protection Agency – EPA – responding to growing public demand for cleaner water, air and land.
Prior to the creation of the EPA the government had no concerted way to regulate and oversee the environmental impact of industrial pollution/emissions.
The EPA has been charged with setting national standards for: emissions and pollutants, issuing permits, overseeing cleanup efforts for past pollution damage.
The EPA works with industry to curb pollution through voluntary pollution control efforts and energy conservation efforts.
In the 1990s President Bill Clinton issued an important order in 1994 that gave the environmental justice movement a boost. He required that the government include environmental justice in its policies and programs. His order also prevented the government from dumping hazardous waste in low-income neighborhoods. It also forced those responsible for the waste to find other solutions. These solutions would need to be safer.
The environmental justice movement is worldwide today. It has come a long way since the 1970s. Environmental justice is essential to sustainability. Environmental justice addresses how people are affected by decisions made about environmental issues. The environmental justice movement helps people consider the connections between those decisions and their impacts on communities.”
excerpted from – What is environmental justice? Gale, Cengage Learning, Newsela staff, 11/16/2017
Sources of environmental ethics
Religious sources
Jewish sources and groups
Environmental Justice, Hazon. Hazon is a Jewish group concerned with sustainability, economic, and environmental social justice.
Coalition on the Environment and Jewish Life (COEJL)
Brit Olam Environmental Justice Cohort: Jewish Texts and Values
Aytzim, the Green Zionist Alliance
Christian sources and groups
“Laudato Si’: On Care for our Common Home” Catholic encyclical on the environment. Pope Francis.
Pope Francis brings spotlight to climate migration
Why Does the Church Care About Global Climate Change, United States Conference of Catholic Bishops’ (USCCB)
Patriarch Bartholomew, the Ecumenical Patriarch of Constantinople, Urges Leaders to Act Now on Climate Change. Orthodox Christianity
A Rocha, international Christian network of environmental organisations
Christian Climate Observer Program (CCOP) part of the Lausanne Creation Care Network and the World Evangelical Alliance.
World Evangelical Alliance’s Sustainability Center
Young Evangelicals for Climate Action (YECA)
Muslim sources and groups
Green Muslims
Islam and Ecology
The Islamic Declaration on Global Climate Change
Islamic declaration on global climate change homepage
Al-Mizan: A Covenant for the Earth
Native American sources and groups
The Indigenous Environmental Network (IEN) is an alliance of grassroots indigenous peoples whose mission is to protect the sacredness of Mother Earth from contamination and exploitation..
As Long as Grass Grows: The Indigenous Fight for Environmental Justice, from Colonization to Standing Rock, Dina Gilio-Whitaker, Beacon Press
Philosophy
Climate Justice, Stanford Encyclopedia of Philosophy
Secular sources
The Principles of Environmental Justice (EJ), People of Color Environmental Leadership Summit
Bali Principles of Climate Justice, August 2002
Related articles
Environmental Justice – What does that mean?
Environmental Justice: The Intersection of Social Equality and Environmentalism
The Connection Between Social and Environmental Justice
Fighting Climate Change Isn’t Just an Environmental Issue — it’s a Social Justice Issue Too
The Shocking Number of Environmentalists Murdered Each Year (worldwide)
Learning Standards
Massachusetts Curriculum FrameworksMassachusetts Curriculum Frameworks
Grades 6–8: Overview of Science and Engineering Practices
Examine and interpret data to describe the role human activities have played in the rise of global temperatures over time; construct, analyze, and/or interpret graphical displays of data and/or large data sets to identify linear and nonlinear relationships; distinguish between causal and correlational relationships in data; consider limitations of data analysis.
8.MS-ESS3-5. Examine and interpret data to describe the role that human activities have played in causing the rise in global temperatures over the past century.
High School. HS-ESS3-5. Analyze results from global climate models to describe how forecasts are made of the current rate of global or regional climate change and associated future impacts to Earth systems.
Clarification: Climate model outputs include both climate changes (such as precipitation and temperature) and associated impacts (such as on sea level, glacial ice volumes, and atmosphere and ocean composition).
A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas
Disciplinary Core Ideas
LS2.C: Ecosystem Dynamics, Functioning, and Resilience
A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions. If a modest biological or physical disturbance to an ecosystem occurs, it may return to its more or less original status (i.e., the ecosystem is resilient), as opposed to becoming a very different ecosystem. Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability. (HS-LS2-2),(HS-LS2-6)
Moreover, anthropogenic changes (induced by human activity) in the environment—including habitat destruction, pollution, introduction of invasive species, overexploitation, and climate change—can disrupt an ecosystem and threaten the survival of some species. (HS-LS2-7)
Cross Cutting Concepts
Cause and Effect: Empirical evidence is required to differentiate between cause and correlation and make claims about specific causes and effects. (HS-LS2-8),(HS-LS4-6)
Scale, Proportion, and Quantity: The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. (HS-LS2-1)
Using the concept of orders of magnitude allows one to understand how a model at one scale relates to a model at another scale. (HS-LS2-2)
Stability and Change: Much of science deals with constructing explanations of how things change and how they remain stable. (HS-LS2-6),(HS-LS2-7)
Next Generation Science Standards
HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.
HS-ESS3-5. Analyze geoscience data and the results from global climate models to make an evidence-based forecast of the current rate of global or regional climate change and associated future impacts to Earth’s systems.
[Clarification: Examples of evidence, for both data and climate model outputs, are for climate changes (such as precipitation and temperature) and their associated impacts (such as on sea level, glacial ice volumes, or atmosphere and ocean composition).]
[Assessment Boundary: Assessment is limited to one example of a climate change and its associated impacts.]
HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.
Social Justice Standards: Learning for Justice
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Antimatter
What is antimatter?
See https://sciencenotes.org/what-is-antimatter-definition-and-examples/
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How was it predicted/discovered?
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How can we harness power from it?
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