Why is the Earth still hot?
How hot is it inside of our world? Well, we see that volcanoes constantly erupts – and they have been doing do for billions of years. Evidently the interior of our planet is seething hot.
If you could have a god’s eye view of the world, see right inside it, it would look something like this:
Photo by RK (c) 2019
Wow! We can clearly see that our world’s interior is full of very hot, glowing, rock! Moving in a bit closer, we’d see hot plumes of magma slowly rising towards the surface, while cooler areas at the surface are pushed mostly sideways, and then begin to descend downwards.
This is all happening slowly of course. We’d to watch for hundreds of thousands of years to clearly see the patterns.
Questions
1. Where did all of this heat energy come from?
2. And since Earth is billions of years old, why hasn’t it cooled down yet?
1. Where did all of this heat come from?
Everything in our Solar Systems – our Sun, the Earth, and the other planets – formed from the gravitational collapse of giant molecular clouds.
Atoms and dust particles are gravitationally attracted to each other, creating larger particles, then pebble-size objects. Over time those objects collided to create rocks of various types (including organic molecules, water, and metals.)
Over longer periods of time those collided to create asteroid-size objects, and then eventually planet size objects.
Big pieces orbited around the huge center of mass, which became our star, the Sun.
Over time those bigger pieces (proto planets) swept up all the material in their path – they cleared the neighborhood of their orbit.
This process created Earth and other similar worlds: Venus, Mars, and Mercury.
We think of Earth as if it were solid, but over long time scales the interior is closer to a liquid – hotter regions expand and rise, cooler regions contract and sink.
Because of this, heavier elements, like iron, would quickly have sunk to the core. In just 10 to 100 million years. This would also pull down any other elements bound to that iron. As such, most of the Earth’s interior is metal, while most of the crust is rock.
We can see this in more detail here – the formation of our solar system
2. And since Earth is billions of years old, why hasn’t it cooled down yet?
This section includes quotes from Radioactive potassium may be major heat source in Earth’s core, Robert Sanders, UC Berkeley News, 12/13/2003
When the Earth was first formed this material was not solid; some was hot enough to become viscous (like silly putty) or even liquid (like lava.)
The denser material was mostly iron and some radioactive metals.
This dense metal slowly sank towards the center, while less dense rock floated upwards.
This process itself created a lot of friction, which created a lot of heat.
“Gradually, however, the Earth would have cooled off and become a dead rocky globe with a cold iron ball at the core if not for the continued release of heat by the decay of radioactive elements like: potassium-40, uranium-238 and thorium-232, which have half-lives of 1.25 billion, 4 billion and 14 billion years, respectively.
About one in every thousand potassium atoms is radioactive.”
Heat from the decay of radioactive elements.
Most metals we know are stable. Think of Nickel, Iron, Copper and Gold. If you put them in a box so that they don’t get exposed to oxygen, then they don’t rust, and never change. Millions of years from now they will still be around.
What’s inside metal atoms? Electrons, protons and neutrons. In a metal atom, the number of these particles will normally never change.
Example: Iron-56 26 protons, 30 neutrons, 26 electrons.
But some very large atoms are special: they not stable – they do change, all by themselves. These are called radioactive elements.
Uranium-238 92 protons, 146 neutrons, 92 electrons
-> spontaneously will change into
Plutonium-239 94 protons, 145 neutrons, 94 electrons + heat
— quote —
In sum, there was no shortage of heat in the early earth, and the planet’s inability to cool off quickly results in the continued high temperatures of the Earth’s interior.
In effect, not only do the earth’s plates act as a blanket on the interior, but not even convective heat transport in the solid mantle provides a particularly efficient mechanism for heat loss.
The planet does lose some heat through the processes that drive plate tectonics, especially at mid-ocean ridges. For comparison, smaller bodies such as Mars and the Moon show little evidence for recent tectonic activity or volcanism.
We derive our primary estimate of the temperature of the deep earth from the melting behavior of iron at ultrahigh pressures.
We know that the earth’s core depths from 2,886 kilometers to the center at 6,371 kilometers (1,794 to 3,960 miles), is predominantly iron, with some contaminants.
How? The speed of sound through the core (as measured from the velocity at which seismic waves travel across it) and the density of the core are quite similar to those seen in of iron at high pressures and temperatures, as measured in the laboratory.
Iron is the only element that closely matches the seismic properties of the earth’s core and is also sufficiently abundant present in sufficient abundance in the universe to make up the approximately 35 percent of the mass of the planet present in the core.
The earth’s core is divided into two separate regions: the liquid outer core and the solid inner core, with the transition between the two lying at a depth of 5,156 kilometers (3,204 miles).
Therefore, If we can measure the melting temperature of iron at the extreme pressure of the boundary between the inner and outer cores, then this lab temperature should reasonably closely approximate the real temperature at this liquid-solid interface.
Scientists in mineral physics laboratories use lasers and high-pressure devices called diamond-anvil cells to re-create these hellish pressures and temperatures as closely as possible.
Those experiments provide a stiff challenge, but our estimates for the melting temperature of iron at these conditions range from about 4,500 to 7,500 kelvins (about 7,600 to 13,000 degrees F).
As the outer core is fluid and presumably convecting (and with an additional correction for the presence of impurities in the outer core), we can extrapolate this range of temperatures to a temperature at the base of Earth’s mantle (the top of the outer core) of roughly 3,500 to 5,500 kelvins (5,800 to 9,400 degrees F) at the base of the earth’s mantle.
The bottom line here is simply that a large part of the interior of the planet (the outer core) is composed of somewhat impure molten iron alloy.
The melting temperature of iron under deep-earth conditions is high, thus providing prima facie evidence that the deep earth is quite hot.
Gregory Lyzenga is an associate professor of physics at Harvey Mudd College. He provided some additional details on estimating the temperature of the earth’s core:
How do we know the temperature? The answer is that we really don’t–at least not with great certainty or precision. The center of the earth lies 6,400 kilometers (4,000 miles) beneath our feet, but the deepest that it has ever been possible to drill to make direct measurements of temperature (or other physical quantities) is just about 10 kilometers (six miles).
Ironically, the core of the earth is by far less accessible more inaccessible to direct probing than would be the surface of Pluto. Not only do we not have the technology to “go to the core,” but it is not at all clear how it will ever be possible to do so.
As a result, scientists must infer the temperature in the earth’s deep interior indirectly. Observing the speed at which of passage of seismic waves pass through the earth allows geophysicists to determine the density and stiffness of rocks at depths inaccessible to direct examination.
If it is possible to match up those properties with the properties of known substances at elevated temperatures and pressures, it is possible (in principle) to infer what the environmental conditions must be deep in the earth.
The problem with this is that the conditions are so extreme at the earth’s center that it is very difficult to perform any kind of laboratory experiment that faithfully simulates conditions in the earth’s core.
Nevertheless, geophysicists are constantly trying these experiments and improving on them, so that their results can be extrapolated to the earth’s center, where the pressure is more than three million times atmospheric pressure.
The bottom line of these efforts is that there is a rather wide range of current estimates of the earth’s core temperature. The “popular” estimates range from about 4,000 kelvins up to over 7,000 kelvins (about 7,000 to 12,000 degrees F).
If we knew the melting temperature of iron very precisely at high pressure, we could pin down the temperature of the Earth’s core more precisely, because it is largely made up of molten iron.
But until our experiments at high temperature and pressure become more precise, uncertainty in this fundamental property of our planet will persist.
— end quote —
What will happen when the Earth finally cools?
When the Earth’s core finally does cool – billions of years from now – then Earth will solidify and there will be no more plate tectonics. Therefore there will be
-
No more earthquakes
-
No more volcanic eruptions
-
no more island building
-
No more mountain building
The Earth’s surface will eventually be eroded down to a flatter surface, marred only by new impact craters.
Earth will then be a geologically dead planet, like the Moon.
Some scientists estimate that “The planet is now cooling about 100°C every 1 billion years, so eventually, maybe several billions of years from now, the waning rays of a dying sun will shine down on a tectonically dead planet whose continents are frozen in place.”
How do we know what lies at the Earth’s core?
How we know what lies at the Earth’s core. BBC
Addressing misconceptions
If the Earth’s core is radioactive why is there no radiation at the surface?
Click the link to read the article, but short version, there indeed is radioactivity here on the Earth’s surface!
External resources and discussions
What percent of the Earth’s core is uranium? earthscience.stackexchange.com
Claim: Radioactive decay accounts for half of Earth’s heat, and related, What Keeps the Earth Cooking? Berkeley Lab scientists join their KamLAND colleagues to measure the radioactive sources of Earth’s heat flow
A fascinating although somewhat controversial article, Andrault, Denis & Monteux, J. & Le Bars, Michael & Samuel, H.. (2016). The deep Earth may not be cooling down. Earth and Planetary Science Letters. 443. 10.1016/j.epsl.2016.03.020.
_________________________________________
This website is educational. Materials within it are being used in accord with the Fair Use doctrine, as defined by United States law.
§107. Limitations on Exclusive Rights: Fair Use. Notwithstanding the provisions of section 106, the fair use of a copyrighted work, including such use by reproduction in copies or phone records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use, the factors to be considered shall include: the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes; the nature of the copyrighted work; the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and the effect of the use upon the potential market for or value of the copyrighted work. (added pub. l 94-553, Title I, 101, Oct 19, 1976, 90 Stat 2546)
Teaching science with augmented reality
Using virtual reality in the classroom
We learn through lectures and reading. We especially learn through illustrations, photographs, diagrams, and animations. But a limitation is that so many of these images are flat, two-dimensional. Not surprisingly, many folks have trouble visualizing what a system is really like, if they only have two dimensional pictures.
An obvious practical solution is to make a lesson hands-on: Students can take a field trip to see gears and machines in a power plant; see ancient ruins on site; travel to a valley and fly over a vast ecosystem to see different parts of the environment. But there’s only so much that a school can do in practice: we can’t purchase every manipulative and lab, or travel to see every place that we talk about.
Yet with today’s technology we can actually model machines, cells, valleys and volcanoes, ecosystems, distance cities, and archaeological sites, in three dimensions – and then bring all of this into the classroom. We bring these models in to a virtual space that students can explore.
And that’s what we are already doing in our classrooms! First, let’s learn a few terms: XR, AR, and VR.
XR- Extended Reality
the emerging umbrella term for all immersive computer virtual experience technologies. These technologies AR, VR, and MR.
Augmented Reality (AR)
When virtual information and objects are overlaid on the real world. This experience enhances the real world with digital details such as images, text, and animation. This means users are not isolated from the real world and can still interact and see what’s going on in front of them.
CRISPR enzyme floating in three dimensions.
Photo by RK (c) 2019
Virtual Reality (VR)
Users are fully immersed in a simulated digital environment. Individuals must put on a VR headset or head-mounted display to get a 360 -degree view of an artificial world. This fools their brain into believing they are walking on the moon, swimming under the ocean or stepped into whatever new world the VR developers created.
A team of researchers at ESA’s mission control centre in Darmstadt, Germany, are investigating new concepts for controlling rovers on a planet and satellites in orbit. Image from the ESA, esa.int/ESA_Multimedia/Images/2017/07/Reality_check
Mixed reality (MR), aka Hybrid Reality
Digital and real-world objects co-exist and can interact with one another in real-time. This experience requires an MR headset… Microsoft’s HoloLens is a great example that, e.g., allows you to place digital objects into the room you are standing in and give you the ability to spin it around or interact with the digital object in any way possible.
Image from Microsoft
Excerpts of these definitions from Bernard Marr, What Is Extended Reality Technology? A Simple Explanation For Anyone, Forbes, 8/12/2019
Augmented reality in Ecology & Environmental Science
When students actively participate in augmented reality learning, the class is effectively a lab, as opposed to being a lecture. Here we are studying ecosystems with an app from the World Wildlife Foundation, WWF Rivers.
Photo by RK (c) 2019
This student has their head in the clouds 😉
Photo by RK (c) 2019
Here we are using the Google Expeditions app, on a Pixel 3A smartphone. The plug-in is “Earth Geology” by Vida systems. For more details see Google Expeditions – Education in VR.
AR in Earth Science
As we walk around the room, we see the Earth and all of it’s layers in a realistic 3D view. Here we stood above the arctic circle, and took screenshots as we moved down latitude, until we were above the antarctic.
Photo by RK (c) 2019
Photo by RK (c) 2019
AR in Physics & Engineering
A simple machine is a mechanical device that changes the direction or magnitude of a force. They are the simplest mechanisms that use mechanical advantage to multiply force.
Here we are examining gears, including bicycle gears.
Photo by RDK (c) 2019
Related Special Education topics
If you can’t visually imagine things, how can you learn?
If someone can’t visually imagine things, how can you learn? We know some people can’t conjure up mental images. But we’re only beginning to understand the impact this “aphantasia” might have on their education.
A discussion of an inability to form mental images , congenital aphantasia. This is believed to affect 2% of the population.
by Mo Costandi, Jun 2016, The Guardian, UK
Learning Standards
What kind of learning standards will students address when using augmented reality science lessons?
NGSS Cross-Cutting Concepts
6. Structure and Function – The way an object is shaped or structured determines many of its properties and functions: Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the shapes, composition, and relationships among its parts; therefore, complex natural and designed structures/systems can be analyzed to determine how they function
Massachusetts Digital Literacy and Computer Science (DLCS) Curriculum Framework
Modeling and Simulation [6-8.CT.e] – 3. Select and use computer simulations, individually and collaboratively, to gather, view, analyze, and report results for content-related problems (e.g., migration, trade, cellular function).
Digital Tools [9-12.DTC.a] – 2. Select digital tools or resources based on their efficiency and effectiveness to use for a project or assignment and justify the selection.
American Association of School Librarians: Standards Framework for Learners
1. Inquire: Build new knowledge by inquiring, thinking critically, identifying problems, and developing strategies for solving problems
Advanced Placement Computer Science Principles
AP-CSP Curriculum Guides
LO 3.1.3 Explain the insight and knowledge gained from digitally processed data by using appropriate visualizations, notations, and precise language.
EK 3.1.3A Visualization tools and software can communicate information about data.
EK 3.1.3E Interactivity with data is an aspect of communicating.
MCAS Classification
MCAS Classification questions
32. The table below shows the classifications of three different sea lions.
a. Identify which two of the sea lions are most closely related.
b. Justify your answer to part (a).
c. Describe and explain two types of evidence scientists would have used to determine the proper classifications of these three sea lions.
____________________
____________________
2016.
5. A scientist concludes that two organisms belong to the same species within the
class Mammalia. Which of the following observations most likely led the scientist
to conclude that the organisms are the same species?
A. The organisms move in the same way.
B. The organisms live in the same habitat.
C. The organisms are nocturnal and carnivorous.
D. The organisms mate and produce fertile offspring.
____________________
24. The brush mouse and the northwestern deermouse are both classified in the
genus Peromyscus. Which of the following conclusions can be made from this information?
A. The two types of mice live in the same habitat.
B. The two types of mice have the same fur color.
C. The two types of mice are closely related to each other.
D. The two types of mice can successfully interbreed with each other.
____________________
32. The table below gives the common names, scientific names, and known geographic locations of several wild cats.
a. Using their common names, identify all the wild cats listed in the table that belong to the same genus.
b. Identify and explain one type of evidence scientists could have used to classify these wild cats.
The three kinds of tigers listed in the table are all classified as one species.
c. Based on the information in the table, identify which kind of tiger has the greatest chance of becoming a separate species. Explain your answer.
d. Describe how scientists could determine if one of the kinds of tigers becomes a separate species.
____________________
33. The table below shows taxonomic information for the gray wolf and four other species.
Based on this information, which of the following lists the species in order from most closely related to least closely related to the gray wolf ?
A. 1, 2, 3, 4
B. 1, 2, 4, 3
C. 2, 1, 3, 4
D. 2, 1, 4, 3
31. All organisms classified in kingdom Animalia must also be classified as
which of the following?
A. Archaea
B. Eubacteria
C. Eukaryota
D. Protista
____________________
45. A student researching bears found the chart below in a textbook. The chart shows the
classifications of several types of bears.
Which of the following conclusions is best supported by the data given in this chart?
A. Modern bears evolved from species that are now extinct.
B. The short-faced bear was the ancestor of the Asiatic black bear.
C. Present day bear species are more closely related than their ancestors were.
D. Natural selection favored the brown bear over the American black bear. .
MCAS Plants
MCAS Plant questions from the Biology MCAS
____________________
31. A plant species growing along a coast produces seeds with fluffy hair-like
fibers on one end. A seed from one of the plants is shown below:
Some of these seeds were dispersed by the wind to islands off the coast, where new plants grew. Within 10 years, the seeds of the island plants were different
from the seeds of the mainland plants. Compared to the mainland seeds, the
island seeds were heavier and had shorter hair-like fibers. Which of the following statements best explains why heavier seeds with shorter fibers were favored in the island environment?
A. These seeds carried more genes than the mainland seeds did.
B. These seeds were less likely to be blown off the island by wind.
C. The island plants needed to prevent animals from eating the seeds.
D. The island plants used more energy to produce heavy seeds than to grow.
____________________
33. Students investigated the effect of acid rain on photosynthesis. Several plants
were given water with a pH of 4 each day for two months. The results showed
that the plants had a reduced rate of photosynthesis.
How did the acidic water most likely reduce the plants’ rate of photosynthesis?
A. by storing excess oxygen produced by the plants
B. by changing the effectiveness of enzymes in the plants
C. by causing root hairs to grow on the roots of the plants
D. by increasing the amount of carbon dioxide taken in by the plants
____________________
34. Waxes form a waterproof coating over the stems and leaves of many terrestrial plants. The waxes are composed of fatty acids linked to long-chain alcohols. Based on this information, waxes are which type of organic molecule?
A. lipids . B. nucleotides . C. polysaccharides . D. proteins
____________________
37. Maltose is a carbohydrate molecule that provides energy to plants early in their
life cycle. Which elements are most common in a molecule of maltose?
A. carbon and hydrogen
B. copper and nitrogen
C. iron and phosphorus
D. magnesium and sulfur
____________________
Algae, and the scientific method
The rate of photosynthesis in organisms depends in part on the wavelength of visible light. In the late 1800s, Thomas Engelmann demonstrated the relationship between the wavelength of light and the rate of photosynthesis. His experiment is described below.
• Engelmann used a prism to produce a visible light spectrum of violet, blue, green, yellow, orange, and red light.
• He shined the light spectrum onto cells of the algae Spirogyra.
• Once the light was shining on the Spirogyra cells, Engelmann added aerobic bacteria to the system. Aerobic bacteria need oxygen to live and grow.
• After adding the bacteria, Engelmann observed the regions of the light spectrum where the bacteria concentrated around the Spirogyra cells.
The setup and results of Engelmann’s experiment are represented by the diagram below:
Mark your answers to multiple-choice questions 8 through 11 in the spaces provided in your Student Answer Booklet. Do not write your answers in this test booklet, but you may work out solutions to multiple-choice questions in the test booklet.
8. Why are the greatest numbers of aerobic bacteria found at the 400–500 nm and 600–700 nm wavelengths of light?
A. Photosynthesis rates are highest there, producing large amounts of water.
B. Photosynthesis rates are highest there, producing large amounts of oxygen.
C. Photosynthesis rates are lowest there, producing small amounts of glucose.
D. Photosynthesis rates are lowest there, producing small amounts of carbon dioxide.
9. What is the role of visible light when Spirogyra cells perform photosynthesis?
A. It provides the energy for the photosynthesis reaction.
B. It concentrates the photosynthesis products for export.
C. It activates the DNA that directs the photosynthesis reaction.
D. It transports photosynthesis reactants across the cell membrane.
10. What is exchanged between the Spirogyra and the bacteria in
Engelmann’s experiment?
A. DNA and RNA
B. starch granules and spores
C. chlorophyll and cytoplasm
D. oxygen and carbon dioxide
11. A scientist used Engelmann’s data to predict how the concentrations of different substances in and around Spirogyra cells will change when the cells are exposed to different wavelengths of light. A graph for one substance is shown below.
What is represented on the y-axis?
A. chlorophyll concentration . B. hydrogen concentration
C. oxygen concentration . D. water concentration
____________________
3. All corn plants contain the ZmLA1 gene. Some corn plants contain a certain mutation in the ZmLA1 gene. The graph below shows the amount of ZmLA1 RNA produced in plants with the normal gene and in plants with the mutated gene.
Based on the graph, what most likely happens in corn plant cells as a direct result of the mutated gene?
A. DNA replication increases.
B. Lipid production decreases.
C. Glucose synthesis increases.
D. Protein production decreases.
____________________
4. The growth of plants in many ecosystems is limited by the supply of
nitrogen. Which of the following groups of organisms plays the largest role in
moving nitrogen between the atmosphere and plants?
A. bacteria . B. earthworms . C. insects . D. protists
____________________
7. Lithops are multicellular organisms found in sandy soil in deserts. They
have large, central vacuoles in their cells that store water. Which of the following best classifies lithops?
A. They are bacteria because they store water.
B. They are animals because they are multicellular.
C. They are fungi because they are found in sandy soil.
D. They are plants because they have large, central vacuoles.
____________________
14. There are many fungus species that live inside plant tissues. What determines
whether the relationship between a fungus and a plant is commensalism,
mutualism, or parasitism?
A. where the fungus is located in the plant
B. how long the fungus survives in the plant
C. whether the fungus reproduces in the plant with spores, seeds, or runners
D. whether the effect of the fungus on the plant is neutral, positive, or negative
____________________
37. Plants in floodplains often get covered by water during floods. Some
plants survive the floods because they can continue photosynthesis
underwater. However, the plants’ rates of photosynthesis are much lower
underwater than above water.
Which of the following helps to explain why the rates of photosynthesis are
lower underwater than above water?
A. There is too much oxygen in the water.
B. There is no carbon dioxide in the water.
C. The chloroplasts do not function underwater.
D. The available light is less intense underwater.
____________________
17. Carbon fixation is an important part of the carbon cycle. Carbon fixation is the conversion of carbon dioxide into organic compounds such as glucose. Which of the following organisms cannot fix carbon?
A. grass
B. green algae
C. mushrooms
D. oak trees
____________________
3. A botanist studied two groups of rice plants to determine how they are related. Both groups of plants have similar shapes, but one group has longer stalks. When the botanist cross-pollinated plants from one group with plants from the other group, the seeds produced did not sprout or grow.
Which of the following conclusions is best supported by this information?
A. The two groups are the same species because the plants have similar shapes.
B. The two groups are different species because they have differently sized stalks.
C. The two groups are different species because the seeds produced cannot sprout or grow.
D. The two groups are the same species because the plants were cross-pollinated and produced seeds
____________________
20. A partial food web is shown below. Which organisms in the food web are both primary and secondary consumers?
A. bluegills
B. cattails
C. coyotes
D. snakes
____________________
28. A student looks at a cell under a microscope. Which of the following
observations would indicate that the cell is from a plant rather than an animal?
A. a nucleus located inside of the cell
B. numerous cilia on the outside of the cell
C. chloroplasts in the cytoplasm of the cell
D. a thin membrane around the edge of the cell
____________________
30. Prolonged periods of drought in an area cause decreases in plant population
sizes. Which of the following statements describes how the decreases in plant
population sizes then affect other populations in the area?
A. Omnivore population sizes increase, and herbivore population sizes increase.
B. Omnivore population sizes decrease, and carnivore population sizes increase.
C. Herbivore population sizes increase, and carnivore population sizes decrease.
D. Herbivore population sizes decrease, and carnivore population sizes decrease.
Pseudoscience
Resource under construction
Introduction
Pseudoscience is a belief system which tries to gain legitimacy by wearing the trappings of science, but fails to abide by the rigorous methodology and standards of evidence that are the marks of actual science.
Pseudoscientists adopt the vocabulary of science, describing conjectures as hypotheses, theories, or laws, providing “evidence” from observation and “expert” testimonies, or developing what appear to be mathematical models of their ideas. However, in pseudoscience there is no attempt to follow the scientific method, provide falsifiable predictions, or develop double blind experiments.
Intro adapted from RationalWiki
Pseudoscience is characterized by:
contradictory, exaggerated or unfalsifiable claims
reliance on confirmation bias rather than rigorous attempts at refutation
lack of openness to evaluation by other experts
absence of systematic practices when developing hypotheses
continued adherence long after the pseudoscientific hypotheses have been experimentally discredited.
(list here adapted from Wikipedia)
Examples
Facts and fiction of the Schumann resonance
If ANY of these claims were actually workable then…
Image from xkcd.com/808/
How to identify red flags
Below are red flags that a supposedly “scientific” claim is in fact pseudoscience.
These essays are from Graham Coghill’s ScienceOrNot. He has articles on indicators of good science (Hallmarks of Science) and indicators of bad science (Science Red Flags).
These are covered by a Creative Commons License.
 |
The ‘scientifically proven’ subterfuge. |
Scammers and deniers use two forms of this tactic:
|
|
|
Persecuted prophets and maligned mavericks: The Galileo Gambit. |
Users of this tactic will try to persuade you that they belong to a tradition of maverick scientists who have been responsible for great advances despite being persecuted by mainstream science. |
|
|
Empty edicts – absence of empirical evidence |
This tactic shows up when people make claims in the form of bald statements – “this is the way it is” or “this is true” or “I know/believe this” or “everybody knows this” – without any reference to supporting evidence. |
|
Anecdotes, testimonials and urban legends |
Those who use this tactic try to present stories about specific cases or events as supporting evidence. The stories range from personal testimonials, to anecdotes about acquaintances, to tales about unidentifiable subjects. |
|
|
Charges of conspiracy, collusion and connivance |
Conspiracy theorists usually start by targeting weaknesses in an accepted model, then propose a conspiracy that explains why their ‘better’ model has been suppressed.Although there can be overwhelming evidence favouring the accepted model, they claim that this simply means the conspiracy has been successful. |
|
|
Stressing status and appealing to authority |
People who use this tactic try to convince you by quoting some ‘authority’ who agrees with their claims and pointing to that person’s status, position or qualifications, instead of producing real-world evidence. The tactic is known as the argument from authority. |
|
|
Devious deception in displaying data: Cherry picking |
In cherry-picking, people use legitimate evidence, but not all of the evidence. They select segments of evidence that appear to support their argument and hide or ignore the rest of the evidence which tends to refute it. |
|
|
Repetition of discredited arguments – parroting PRATT |
In this tactic, people persist in repeating claims that have been shown over and over to have no foundation. Look for slogans, sweeping statements or claims that look as though they could easily be refuted. |
|
|
Duplicity and distraction – false dichotomy |
In this tactic, people assert that there are only two possible (and usually opposite) positions to choose from, when in fact there are more.They try to argue that if one position is shown to be false, then the other must be correct. |
|
|
Wishful thinking – favouring fantasy over fact |
We all fall victim to this tactic because we use it on ourselves. We like to believe things that conform with our wishes or desires, even to the extent of ignoring evidence to the contrary. |
|
|
Appeals to ancient wisdom – trusting traditional trickery |
People who use this tactic try to persuade you that a certain explanation, treatment or model must be correct because it’s been around for a long time. |
|
Technobabble and tenuous terminology: the use of pseudo scientific language |
In this tactic, people use invented terms that sound “sciencey” or co-opt real science terms and apply them incorrectly. |
|
|
Confusing correlation with causation: rooster syndrome |
This is the natural human tendency to assume that, if two events or phenomena consistently occur at about the same time, then one is the cause of the other.Hence “rooster syndrome”, from the rooster who believed that his crowing caused the sun to rise. |
|
|
Straw man: crushing concocted canards |
When this tactic is used, it’s always in response to an argument put up by an opponent. Unable to come up with a reasoned response, the perpetrator constructs a distorted, incorrect version (the “straw man”) of the opponent’s argument, and then proceeds to tear it to shreds. |
|
Indelible initial impressions: the anchoring effect |
Anchoring is the human tendency to rely almost entirely on one piece of evidence or study, usually one that we encountered early, when making a decision. |
|
|
Perceiving phoney patterns: apophenia |
This happens when you convince yourself, or someone tries to convince you, that some data reveal a significant pattern when really the data are random or meaningless. |
|
|
Esoteric energy and fanciful forces. |
This tactic is easy to pick because people who use it try to convince you that some kind of elusive energy or power or force is responsible for whatever effect they are promoting. |
|
Banishing boundaries and pushing panaceas – applying models where they don’t belong |
Those who use this tactic take a model that works under certain conditions and try to apply it more widely to circumstances beyond its scope, where it does not work. Look for jargon, sweeping statements and vague, rambling “explanations” that try to sound scientific. |
|
|
Averting anxiety with cosmic connectivity: magical thinking |
Magical thinking is present when anyone argues that everything is connected: thoughts, symbols and rituals can have distant physical and mental effects; inanimate objects can have intentions and mystical influences.Often, the connectivity is supposedly mediated by some mysterious energy, force or vibration and there is much talk of holism, resonance, balance, essences and higher states. |
|
Single study syndrome – clutching at convenient confirmation |
This tactic shows up when a person who has a vested interest in a particular point of view pounces on some new finding which seems to either support or threaten that point of view. It’s usually used in a context where the weight of evidence is against the perpetrator’s view. |
|
|
Appeal to nature – the authenticity axiom |
You are expected to accept without question that anything ‘natural’ is good, and anything ‘artificial’, ‘synthetic’ or ‘man-made’ is bad. |
|
|
The reversed responsibility response – switching the burden of proof |
This tactic is usually used by someone who’s made a claim and then been asked for evidence to support it. Their response is to demand that you show that the claim is wrong and if you can’t, to insist that this means their claim is true. |
|
The scary science scenario – science portrayed as evil. |
The perpetrators try to convince you that scientific knowledge has resulted in overwhelmingly more harm than good.They identify environmental disasters, accidents, human tragedies, hazards, weapons and uncomfortable ideas that have some link to scientific discoveries and claim that science must be blamed for the any damage they cause.They may even go so far as claiming that scientists themselves are generally cold, unfeeling people who enjoy causing harm. |
|
False balance – cultivating counterfeit controversy to create confusion |
This tactic is promoted by peddlers of bad science and pseudoscience and is often taken up by journalists and politicians. In discussing an issue, they insist that “both sides” be presented.Many journalists routinely look for a representative of each “side” to include in their stories, even though it might be inappropriate.Groups or individuals who are pushing nonsense or marginal ideas like to exploit this tendency so that their point of view gains undeserved publicity. |
|
Confirmation bias – ferreting favourable findings while overlooking opposing observations |
This is a cognitive bias that we all suffer from. We go out of our way to look for evidence that confirms our ideas and avoid evidence that would contradict them. |
|
Crafty contrarians and wily watchdogs – donning the mantle of shrewdness |
This is an attitude adopted by a person – and it’s usually an older male – who has achieved success within his profession. This person feels entitled to make pronouncements about areas in which he has no competence.He believes he has developed a knack for making good judgements based on ‘intuition’ or ‘gut feeling’ and you are expected to respect his opinions because of his reputation for astuteness. His opinions are usually at odds with the accepted science. |
|
|
The appeal to common sense – garbage in the guise of gumption |
The perpetrator tries to persuade you to accept or reject a claim based on what’s supposedly “common sense”.Look out for key words such as “Obviously, …”, “Naturally, …”,
|
|
Ostensible oppression of opposing opinions – claims of rights violated. |
In this tactic, people insist that their right to express their opinion, or their right to free speech, is being denied. This is their reaction to having their opinions dismissed, rejected or ignored by mainstream scientific forums.They refuse to accept that their opinions fail because they do not meet the standards for publication in those forums. |
|
|
The alarmism accusation – claims of crises created to funnel funding. |
Those who use this tactic insist that the current scientific consensus on some issue is corrupt. This, they claim, is because a group of scientists has colluded to hype the position which favours its own interests.The purported motive is to attract funding for their research. Look for derisive terms such as “follow the money” or “pal review”. |
Consilience: Converging lines of evidence
One of the biggest misunderstandings about science is the idea that scientists reach conclusions by “consensus.” This sounds dangerously like democracy. While democracy is great for a free nation, one can’t vote on reality. Scientists can’t vote on “Should Earth have one moon or two moons? Should the Earth be 1000 years old or billions of years old?’ There’s no voting to create a consensus in science.
In reality the process goes in the other direction: the appearance of consensus among scientists isn’t caused by voting. Consensus only appears if all evidence, from independent people, in different situations, always leads towards the same conclusion.
Michael Crichton says it well:
I want to pause here and talk about this notion of consensus, and the rise of what has been called consensus science. I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled.
Let’s be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world.
In science consensus is irrelevant. What is relevant is reproducible results. …
Michael Crichton, Caltech lecture, 2003
Richard Feyman says the same thing:
If [a consensus] disagrees with experiment, it’s wrong. In that simple statement is the key to science. It doesn’t make any difference how beautiful your guess is, it doesn’t matter how smart you are who made the guess, or what his name is … If it disagrees with experiment, it’s wrong.
We may draw highly certain conclusions when we have many converging lines of evidence.
Consilience is the principle that evidence from independent, unrelated sources can converge on strong conclusions.
Examples: Is the tooth fairy real?
How do children get money from the supposed tooth fairy?
Lines of evidence that one might present as being for the existence of said tooth fairy:
tba
Lines of evidence that the money actually comes from parents:
tba
Result: the converging lines of evidence suggests that tooth fairy money really does comes from the parents.
Point: Even if we do not have perfect knowledge we can come to reasonable conclusions when all of the evidence points in the same direction.
Example: Ancient age of the Earth
Some people say that the planet Earth is only thousands of years. Others say that it is billions of years old.
How do we decide? Consilience.
A. There are only divergent lines of evidence for young Earth claims
B. All lines of evidence converge on the ancient Earth claim
Example: Life evolved through evolution
Some people say that life was created all at once, recently, and has had almost no changes. Others say that life developed through evolution by natural selection, and that much change has occurred over billions of years.
How do we decide? Consilience.
A. There are only divergent lines of evidence for creationism.
B. All lines of evidence converge on the slow development of life over billions of years.
Additional reading
Established scientific models are supported by multiple independent lines of evidence.
Multiple lines of reasoning in support of one claim
The logic of scientific arguments
How science lets us analyze competing ideas.
Example of consilience in Astronomy, evidence for the Big Bang
Could there be a shadow biosphere?
Could there be a shadow biosphere here on Earth?
I. Life on Earth, but not as we know it?
This section excerpted from Life on Earth… but not as we know it,
Robin McKie, The Guardian (UK), 4/13/2013
These researchers believe life may exist in more than one form on Earth: standard life – like ours – and “weird life”, as they term the conjectured inhabitants of the shadow biosphere.
All the micro-organisms that we have detected on Earth to date have had a biology like our own: proteins made up of a maximum of 20 amino acids and a DNA genetic code made out of only four chemical bases: adenine, cytosine, guanine and thymine,” says Cleland.
“Yet there are up to 100 amino acids in nature and at least a dozen bases. These could easily have combined in the remote past to create lifeforms with a very different biochemistry to our own. More to the point, some may still exist in corners of the planet.”
Science’s failure to date to spot this weird life may seem puzzling. The natural history of our planet has been scrupulously studied and analysed by scientists, so how could a whole new type of life, albeit a microbial one, have been missed?
Cleland has an answer. The methods we use to detect micro-organisms today are based entirely on our own biochemistry and are therefore incapable of spotting shadow microbes, she argues. A sample of weird microbial life would simply not trigger responses to biochemists’ probes and would end up being thrown out with the rubbish.
That is why unexplained phenomena like desert varnish are important, she says, because they might provide us with clues about the shadow biosphere. We may have failed to detect the source of desert varnish for the simple reason that it is the handiwork of weird microbes which generate energy by oxidising minerals, leaving deposits behind them.
The idea of the shadow biosphere is also controversial and is challenged by several other scientists.
Biological Dark Matter
This section is originally from ‘Dark Matter’ in Biology, Ian Dunn, Biopolyverse, 3/21/2011.
That website no longer exists, so we present this here as a resource for our students.
… All current examples of ‘biological dark matter’ cited in the literature are, in essence, uncharacterized manifestations of known types of entities. Consider the issue of ‘dark’ products of complex genomes, in the form of numerous transcribed RNAs with unknown functions. However exotic the biological roles of certain non-coding RNAs, the general chemical nature of any RNA molecule is very familiar …
A strict analogical extension of cosmic to biological dark matter would then be the discovery of a biological effect that cannot be accounted for by ‘ordinary’ biological mediators or processes. And just as dark matter in the universe is a recent finding, such a hypothetical biological effect might itself be long unrecognized, rendering the agency involved truly obscured.
… there are levels and levels of ‘darkness’ in any area of investigation, not least of which is biology. In other words, a hierarchy of novelty / unfamiliarity / strangeness can be readily constructed when we consider new biological discoveries, and speculate upon their ‘outer limits’...
Some discoveries may provide interesting precedents for processes or structures hitherto unreported, but without causing too many eyebrows to be raised.
This image from Illuminating the dark matter in metabolomics, Ricardo da Silva, PNAS. http://www.pnas.org/content/112/41/12549
Still other findings may indeed cause considerable supra-ocular hair elevation, yet fall short of seriously challenging key biological principles.
With these considerations in mind, it is not difficult to categorize the experimental input of new biological information as a spectrum of sorts:
‘Dark Matter’ in Biology http://biopolyverse.com/2011/03/21/dark-matter-in-biology/
Extremely hypothetical dark life from actual, cosmological dark matter
This section excerpted from Could Dark Matter Spawn ‘Shadow Life’?
By Ian O’Neill, 2/7/2018, HowStuffWorks
The vast majority of mass in our universe is invisible, and for a while, physicists have been trying really hard to understand what this elusive “stuff” is.
Assumed to be some kind of particle, there are hopes that the Large Hadron Collider might produce a dark matter particle or that a space telescope might detect the obvious gamma-ray telltale signature of dark matter particles colliding. But so far, hints have been few and far between; a problem that’s forcing theoretical physicists to think up new ideas.
In a mind-bending 2017 op-ed for Nautilus, famed theoretical physicist Lisa Randall delved into one of the more extreme possibilities for dark matter. Rather than thinking of dark matter as one type of particle, might dark matter be composed of an entire family of particles that create dark stars, dark galaxies, dark planets and, perhaps, dark life?
This dark universe’s chemistry might be as rich and varied as our “ordinary chemistry.”
…Astrophysicists have hypothesized in the past that “dark stars” — stars made of dark matter — may have existed in our primordial universe and may persist to this day. If this is the case, Randall argues, perhaps “dark planets” may have formed, too.
She then takes this idea a step further: If there’s a family of dark matter particles, governed by forces only accessible in the dark sector, might this realm also have complex chemistry? If so, might there be life? If there is “shadow life” living out its days parallel to our universe, you can forget any hopes of detecting it, however.
Does Dark Matter Harbor Life?
Excerpted from Does Dark Matter Harbor Life? An invisible civilization could be living right under your nose. By Lisa Randall
… The Standard Model contains six types of quarks, three types of charged leptons (including the electron), three species of neutrinos, all the particles responsible for forces, as well as the newly discovered Higgs boson. What if the world of dark matter—if not equally rich—is reasonably wealthy too?…
If we were creatures made of dark matter, we would be very wrong to assume that the particles in our ordinary matter sector were all of the same type. Perhaps we ordinary matter people are making a similar mistake.
Given the complexity of the Standard Model of particle physics, which describes the most basic components of matter we know of, it seems very odd to assume that all of dark matter is composed of only one type of particle. Why not suppose instead that some fraction of the dark matter experiences its own forces?
In that case, just as ordinary matter consists of different types of particles and these fundamental building blocks interact through different combinations of charges, dark matter would also have different building blocks—and at least one of those distinct new particle types would experience non-gravitational interactions….
Ordinary matter’s many components have different interactions and contribute to the world in different ways. So too might dark matter have different particles with different behaviors that might influence the universe’s structure in a measurable fashion.
When first studying partially interacting dark matter, I was astonished to find that practically no one had considered the potential fallacy—and hubris—of assuming that only ordinary matter exhibits a diversity of particle types and interactions….
… Perhaps nuclear-type forces act on dark particles in addition to the electromagnetic-type one. In this even richer scenario, dark stars could form that undergo nuclear burning to create structures that behave even more similarly to ordinary matter than the dark matter I have so far described. In that case, the dark disk could be populated by dark stars surrounded by dark planets made up of dark atoms. Double-disk dark matter might then have all of the same complexity of ordinary matter.
- Lisa Randall is the Frank B. Baird, Jr., Professor of Science at Harvard University, where she studies theoretical particle physics and cosmology.
Tags
#shadowbiosphere #shadowlife #darklife #exobiology
Further reading
Hypothetical types of biochemistry, Wikipedia
Purple Earth Hypothesis, Wikipedia
‘Dark Matter’ in Biology
http://biopolyverse.com/2011/03/21/dark-matter-in-biology/
Paradigms and Biological ‘Dark Matter’
http://biopolyverse.com/2011/03/28/paradigms-and-biological-%E2%80%98dark-matter%E2%80%99/
‘Dark Matter’ in Biology: Great Expectations and Biological Limits
http://biopolyverse.com/2011/04/05/%E2%80%98dark-matter%E2%80%99-in-biology-great-expectations-and-biological-limits/
A Dark Shadow Biosphere with Unorthodox Orthogonality?
http://biopolyverse.com/2011/04/12/a-dark-shadow-biosphere-with-unorthodox-orthogonality/
A Dark Shadow Biosphere with Unorthodox Orthogonality?
Does ‘Dark’ Biology Have Its CHARMs?
http://biopolyverse.com/2011/05/03/does-%E2%80%98dark%E2%80%99-biology-have-its-charms/
Learning Standards
Next Generation Science Standards: Science & Engineering Practices
● Ask questions that arise from careful observation of phenomena, or unexpected results, to clarify and/or seek additional information.
● Ask questions that arise from examining models or a theory, to clarify and/or seek additional information and relationships.
● Ask questions to determine relationships, including quantitative relationships, between independent and dependent variables.
● Ask questions to clarify and refine a model, an explanation, or an engineering problem.
● Evaluate a question to determine if it is testable and relevant.
● Ask questions that can be investigated within the scope of the school laboratory, research facilities, or field (e.g., outdoor environment) with available resources and, when appropriate, frame a hypothesis based on a model or theory.
● Ask and/or evaluate questions that challenge the premise(s) of an argument, the interpretation of a data set, or the suitability of the design
MA 2016 Science and technology
Appendix I Science and Engineering Practices Progression Matrix
Science and engineering practices include the skills necessary to engage in scientific inquiry and engineering design. It is necessary to teach these so students develop an understanding and facility with the practices in appropriate contexts. The Framework for K-12 Science Education (NRC, 2012) identifies eight essential science and engineering practices:
1. Asking questions (for science) and defining problems (for engineering).
2. Developing and using models.
3. Planning and carrying out investigations.
4. Analyzing and interpreting data.
5. Using mathematics and computational thinking.
6. Constructing explanations (for science) and designing solutions (for engineering).
7. Engaging in argument from evidence.
8. Obtaining, evaluating, and communicating information.
Scientific inquiry and engineering design are dynamic and complex processes. Each requires engaging in a range of science and engineering practices to analyze and understand the natural and designed world. They are not defined by a linear, step-by-step approach. While students may learn and engage in distinct practices through their education, they should have periodic opportunities at each grade level to experience the holistic and dynamic processes represented below and described in the subsequent two pages… http://www.doe.mass.edu/frameworks/scitech/2016-04.pdf
Biological differences between men and women impact perception of pain and choice of medication
Biological differences between men and women impact perception of pain and choice of medication
From Wired Magazine – Women’s Pain Is Different From Men’s—the Drugs Could Be Too
Men and Women can’t feel each other’s pain. Literally. We have different biological pathways for chronic pain, which means pain-relieving drugs that work for one sex might fail in the other half of the population.
So why don’t we have pain medicines designed just for men or women? The reason is simple: Because no one has looked for them. Drug development begins with studies on rats and mice, and until three years ago, almost all that research used only male animals. As a result, women in particular may be left with unnecessary pain—but men might be too.
Now a study in the journal Brain reveals differences in the sensory nerves that enter the spinal cords of men and women with neuropathic pain, which is persistent shooting or burning pain. The first such study in humans, it provides the most compelling evidence yet that we need different drugs for men and women.
“There’s a huge amount of suffering that’s happening that we could solve,” says Ted Price, professor of neuroscience at the University of Texas, Dallas, and an author of the Brain article. “As a field, it would be awesome to start having some success stories.”
Modern-day pain control is notoriously dismal. Our go-to medicines—opioids and anti-inflammatories—are just new versions of opium and willow bark, substances we’ve used for thousands of years. Although they are remarkably effective in relieving the sudden pain of a broken bone or pulled tooth, they don’t work as well for people with persistent pain that lasts three months or longer.
Some 50 million people struggle with pain most days or every day, and chronic pain is the leading cause of long-term disability in the United States. Women are more likely than men to have a chronic pain condition, such as arthritis, fibromyalgia, or migraines.
Meanwhile, pain medications are killing us. About 17,000 people die each year from prescribed opioids as clinicians write almost 200 million opioid prescriptions, or more than one for every two American adults.
The failure to include sex differences in the search for better pain relief stems in part from flawed but deep-seated beliefs. “[Medical researchers] made the assumption that men and women were absolutely identical in every respect, except their reproductive biology,” says Marianne Legato, a cardiologist who began sounding an alarm in the 1980s about differences in heart attack symptoms among women. She went on to pioneer a new field of gender-specific medicine.
The physiology of pain is just one of many ways that men and women differ, she says. But she isn’t surprised that no sex-specific medicines have emerged. The medical community—including pharmaceutical companies—didn’t appreciate the variation between men and women, including in their metabolisms, immune systems, and gene expression.
“If there were differences in how their drugs worked between men and women, they didn’t want to hear about it,” she says.
… Tailoring new medicines to men or women would be revolutionary, particularly considering that it took many years for women (and female animals) to get included in pain research at all.
Fearful of potential birth defects, in 1977 the FDA cautioned against including women of childbearing age in clinical trials, which meant women used drugs solely designed for men. By 1993, the thinking had changed, and Congress passed a law requiring the inclusion of women in clinical trials funded by the National Institutes of Health. Although clinical trials now include both men and women, they often don’t report results by sex.
https://www.wired.com/story/womens-pain-is-different-from-mens-the-drugs-could-be-too/
Why the sexes don’t feel pain in the same way
Why the sexes don’t feel pain the same way – After decades of assuming that pain processing is equivalent in all sexes, scientists are finding that different biological pathways can produce an ‘ouch!’. Amber Dance, Nature, 3/27/2019
Robert Sorge was studying pain in mice in 2009, but he was the one who ended up with a headache.
At McGill University in Montreal, Canada, Sorge was investigating how animals develop an extreme sensitivity to touch. To test for this response, Sorge poked the paws of mice using fine hairs, ones that wouldn’t ordinarily bother them. The males behaved as the scientific literature said they would: they yanked their paws back from even the finest of threads.
But females remained stoic to Sorge’s gentle pokes and prods1. “It just didn’t work in the females,” recalls Sorge, now a behaviourist at the University of Alabama at Birmingham. “We couldn’t figure out why.” Sorge and his adviser at McGill University, pain researcher Jeffrey Mogil, would go on to determine that this kind of pain hypersensitivity results from remarkably different pathways in male and female mice, with distinct immune-cell types contributing to discomfort2.
Sorge and Mogil would never have made their discovery if they had followed the conventions of most pain researchers. By including male and female mice, they were going against the crowd. At the time, many pain scientists worried that females’ hormone cycles would complicate results. Others stuck with males because, well, that’s how things were done.
Today, inspired in part by Sorge and Mogil’s work and spurred on by funders, pain researchers are opening their eyes to the spectrum of responses across sexes. Results are starting to trickle out, and it’s clear that certain pain pathways vary considerably, with immune cells and hormones having key roles in differing responses.
This push is part of a broader movement to consider sex as an important variable in biomedical research, to ensure that studies cover the range of possibilities rather than gleaning results from a single population.
Sex differences in pain responses
Current Opinion in Physiology, Volume 6, December 2018, Pages 75-81, by Robert E Sorge, Larissa J Strath
Sex differences have been reported in the experience of pain and in the prevalence of chronic pain conditions. However, recently work has uncovered biological differences in the utilization of immune cells and basic function of afferents that shed light on the underpinnings of these sex-dependent findings. In addition, work in healthy controls and chronic pain patients have highlighted biases in attribution of pain and assessment of pain intensity that further reinforce sex differences.
Together, the combination of biological differences, distinct psychological coping strategies and outside bias result in the maintenance of disparities in the experience of pain based on sex. Recognition of sex differences and the underlying mechanisms can only improve treatment and patient outcomes.
Does Gender Influence Pain Sensitivity?
Biology may play a role in nociception and analgesia, and researchers are examining the potential effects of social and psychologic factors. Neurology Reviews. 2017 May;25(5):16-19
Biologic differences may explain gender differences in pain sensitivity. Research during the past 20 years has suggested that microglia play an important role in nociception. Newer data, however, indicate that microglial involvement in pain may be specific to males. Because the majority of animal research had been performed in male rodents, this observation had not been made previously, said Dr. Mogil.
He and his colleagues injured male and female mice to induce mechanical allodynia. The mice exhibited the same amount of mechanical allodynia, regardless of gender. The investigators next administered minocycline, a glial inhibitor, to the mice. The intervention reversed the allodynia in male mice, but not in female mice. Using fluorocitrate or propentofylline in place of minocycline produces the same result, said Dr. Mogil. Research into the biologic basis for pain modulation in females is ongoing.
All Pain Is Not the Same
Psychologist Discusses Gender Differences in Chronic Pain, Translating Research in Women’s Health and Mental Health to Practice.
Women experience chronic pain longer, more intensely and more often than men, according to a psychologist who works with both men and women dealing with diseases and conditions that leave them suffering.
“Chronic pain affects a higher proportion of women than men around the world,” said Jennifer Kelly, PhD, of the Atlanta Center for Behavioral Medicine. “We need to encourage women to take a more active role in their treatment and reduce the stigma and embarrassment of this problem.”
Speaking Thursday at the 118th Annual Convention of the American Psychological Association, Kelly said the latest research offers interesting insights into how physicians and mental health providers can better treat women with chronic pain.
… The American Psychological Association, in Washington, D.C., is the largest scientific and professional organization representing psychology in the United States and is the world’s largest association of psychologists.
Women suffer needless pain because almost everything is designed for men
Why women are 50 percent more likely to be misdiagnosed after a heart attack and 17 percent more likely to die in a car crash. By Sigal Samuel, Apr 17, 2019, Vox
In medical lore, the term “Yentl syndrome” has come to describe what happens when women present to their doctors with symptoms that differ from men’s — they often get misdiagnosed, mistreated, or told the pain is all in their heads. This phenomenon can have lethal consequences.
Many, many women have had this experience when they go to the doctor. I had it myself, years ago. As a spate of articles about the phenomenon has come out in the past couple of years, more people have begun talking about a “gender pain gap.”
In a new book, Invisible Women: Data Bias in a World Designed for Men, the British journalist and feminist activist Caroline Criado Perez argues that this is part of a larger problem: the “gender data gap.”
Basically, the data our society collects is typically about men’s experience, not women’s. That data gets used to allocate research funding and make decisions about design. Because most things and spaces — from pain medications to cars, and from air-conditioned offices to city streets — have been designed by men with men as the default user, they often don’t work well for women.
Even when researchers do gather data from women as well as men in their studies, they often fail to sex-disaggregate it — to separate out the male and female data they’ve collected and analyze it for differences. That’s crucial, because a new pain medication that’s ineffective for men may work great for women, but you’d never know it if you mixed all their data together.
All this gives rise to a powerful possibility: What if we can reduce suffering for half the population, simply by ceasing to design everything as if it’ll only be used by men?
Criado Perez’s book discusses how biased design shows up pretty much everywhere, but the issues she identifies in the realm of health are the most striking because they’re the most dangerous.
I spoke to Criado Perez about why the medical system treats women’s pain differently, whether we need to design drugs specifically for women, and how she dealt with the gaslighting she experienced while working on the book. A transcript of our conversation, lightly edited for length and clarity, follows.
Not just in humans – gender differences are in other mammals
Sorge RE, Mapplebeck JC, Rosen S, et al. Different immune cells mediate mechanical pain hypersensitivity in male and female mice. Nat Neurosci. 2015;18(8):1081-1083.
A large and rapidly increasing body of evidence indicates that microglia-to-neuron signaling is essential for chronic pain hypersensitivity. Using multiple approaches, we found that microglia are not required for mechanical pain hypersensitivity in female mice; female mice achieved similar levels of pain hypersensitivity using adaptive immune cells, likely T lymphocytes. This sexual dimorphism suggests that male mice cannot be used as proxies for females in pain research.
Gay-Lussac’s law (Amontons’ law)
from the NASA Glenn Research Center website
Gases have various properties that we can observe with our senses, including the gas pressure, temperature (T), mass, and the volume (V) that contains the gas.
Careful, scientific observation has determined that these variables are related to one another and that the values of these properties determine the state of the gas.
The relationship between temperature and volume, at a constant number of moles and pressure, is called Charles and Gay-Lussac’s Law in honor of the two French scientists who first investigated this relationship.
Charles did the original work, which was verified by Gay-Lussac.
They observed that if the pressure is held constant, the volume V is equal to a constant times the temperature T:
V = constant * T
For example, suppose we have a theoretical gas confined in a jar with a piston at the top. The initial state of the gas has a volume qual to 4.0 cubic meters, and the temperature is 300 Kelvin.
With the pressure and number of moles held constant, the burner has been turned off and the gas is allowed to cool to 225 Kelvin. (In an actual experiment, a cryogenic ice-bath would be required to obtain these temperatures.)
As the gas cools, the volume decreases to 3.0 cubic meters.
The volume divided by the temperature remains a constant (4/300 = 3/225 ).
Here is a computer animation of this process:
Examples of where this occurs in real life
TBA
and
Please note, like all the other gas laws, this is not a law of physics. Rather, this is a generally useful rule, but only valid when gas temperature and pressure is low enough for the atoms to usually be far apart from each other.
As we deal with more extreme cases, this rule doesn’t hold up.
Avogadro’s law
Previously in Chemistry one has learned about Avogadro’s hypothesis:
Equal volumes of any gas, at the same temperature and pressure, contain the same number of molecules.
Reasoning
(from Modern Chemistry, Davis, HRW)
In 1811, Avogadro found a way to explain Gay-Lussac’s simple ratios of combining volumes without violating Dalton’s idea of indivisible atoms. He did this by rejecting Dalton’s idea that reactant elements are always in monatomic form when they combine to form products. He reasoned that these molecules could contain more than one atom.
Avogadro also put forth an idea known today as Avogadro’s law: equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
It follows that at the same temperature and pressure, the volume of any given gas varies directly with the number of molecules.
Avogadro’s law also indicates that gas volume is directly proportional to the amount of gas, at a given temperature and pressure.
Note the equation for this relationship.
V = kn
Here, n is the amount of gas, in moles, and k is a constant.
Avogadro’s reasoning applies to the combining volumes for the reaction of hydrogen and oxygen to form water vapor.
Dalton had guessed that the formula of water was HO, because this formula seemed to be the most likely formula for such a common compound.
But Avogadro’s reasoning established that water must contain twice as many H atoms as O atoms, consistent with the formula H2O.
As shown below, the coefficients in a chemical reaction involving gases indicate the relative numbers of molecules, the relative numbers of moles, and the relative volumes.
The simplest hypothetical formula for oxygen indicated 2 oxygen atoms, which turns out to be correct. The simplest possible molecule of water indicated 2 hydrogen atoms and 1 oxygen atom per molecule, which is also correct.
Experiments eventually showed that all elements that are gases near room temperature, except the noble gases, normally exist as diatomic molecules.
As an equation
Avogadro’s Law – also known as Avogadro–Ampère law
when temperature and pressure are held constant:
volume of a gas is directly proportional to the # moles (or # particles) of gas
n1 / V1 = n2 / V2
or
What does this imply?
As # of moles of gas increases, the volume of the gas also increases.
As # of moles of gas is decreased, the volume also decreases.
Thus, # of molecules (or atoms) in a specific volume of ideal gas is independent of their size (or molar mass) of the gas.
Important! This is not a law of physics!
Rather, this is a generally useful rule, which is only valid when gas temperature and pressure is low enough for the atoms to usually be far apart from each other. As we begin to deal with more extreme cases, this rule doesn’t hold up.
At what point does Avogadro’s law not apply?
Example problems
These problems are from The Chem Team, Kinetic Molecular Theory and Gas Laws
Example #1: 5.00 L of a gas is known to contain 0.965 mol. If the amount of gas is increased to 1.80 mol, what new volume will result (at an unchanged temperature and pressure)?
Solution:
I’ll use V1n2 = V2n1
(5.00 L) (1.80 mol) = (x) (0.965 mol)
x = 9.33 L (to three sig figs)
Example #2: A cylinder with a movable piston contains 2.00 g of helium, He, at room temperature. More helium was added to the cylinder and the volume was adjusted so that the gas pressure remained the same. How many grams of helium were added to the cylinder if the volume was changed from 2.00 L to 2.70 L? (The temperature was held constant.)
Solution:
1) Convert grams of He to moles:
2.00 g / 4.00 g/mol = 0.500 mol
2) Use Avogadro’s Law:
V1 / n1 = V2 / n2
2.00 L / 0.500 mol = 2.70 L / x
x = 0.675 mol
3) Compute grams of He added:
0.675 mol – 0.500 mol = 0.175 mol
0.175 mol x 4.00 g/mol = 0.7 grams of He added
Example #3: A balloon contains a certain mass of neon gas. The temperature is kept constant, and the same mass of argon gas is added to the balloon. What happens?
(a) The balloon doubles in volume.
(b) The volume of the balloon expands by more than two times.
(c) The volume of the balloon expands by less than two times.
(d) The balloon stays the same size but the pressure increases.
(e) None of the above.
Solution:
We can perform a calculation using Avogadro’s Law:
V1 / n1 = V2 / n2
Let’s assign V1 to be 1 L and V2 will be our unknown.
Let us assign 1 mole for the amount of neon gas and assign it to be n1.
The mass of argon now added is exactly equal to the neon, but argon has a higher gram-atomic weight (molar mass) than neon. Therefore less than 1 mole of Ar will be added. Let us use 1.5 mol for the total moles in the balloon (which will be n2) after the Ar is added. (I picked 1.5 because neon weighs about 20 g/mol and argon weighs about 40 g/mol.)
1 / 1 = x / 1.5
x = 1.5
answer choice (c).
Example #4: A flexible container at an initial volume of 5.120 L contains 8.500 mol of gas. More gas is then added to the container until it reaches a final volume of 18.10 L. Assuming the pressure and temperature of the gas remain constant, calculate the number of moles of gas added to the container.
Solution:
V1 / n1 = V2 / n2
| 5.120 L | 18.10 L | |
| –––––––– | = | –––––– |
| 8.500 mol | x |
x = 30.05 mol <— total moles, not the moles added
30.05 – 8.500 = 21.55 mol (to four sig figs)
Notice the specification in the problem to determine moles of gas added. The Avogadro Law calculation gives you the total moles required for that volume, NOT the moles of gas added. That’s why the subtraction is there.
.
Latest Posts
-
Is it feasible and safe to colonize Mars?
Over the last decade many people working in space exploration have become much more skeptical about the possibility of human colonization of Mars, at least…
-
Soil profile Lego lab
First let’s learn about soil and its layers – Soil profiles This image comes from Build a Layers of Soil Model by Sarah McClelland. Clicking…
-
Epithelial cell tissue box model
Students can build a realistic model of epithelial cells with a tissue box. Here’s an article on Skin – the integumentary System Using a tissue box…
-
Making a winter cat shelter for outdoor cats
New England winters are beautiful, but they can be awful for feral cats. We have a few cats in our home that we got from…
KaiserScience 