Teaching ionic formulas with Legos as manipulatives
We can use giant Legos as manipulatives to teach students about ionic bonding formulas.
We can explore cation-to-anion ratios.
The blocks may represent trivalent, divalent, and monovalent cations and anions.
from “An Interlocking Building Block Activity
in Writing Formulas of Ionic Compounds”
You might be able to get them at low cost from a community yard sale group. Just label them yourself.
Ruddick and Parrill write
LEGO blocks provide excellent representations of ions, particularly because the blocks are color coded, and the valency of the ion can be represented by the number of “dots”, or raised knobs, on a brick. For example, a blue 1 × 3 brick (1 dot wide and 3 dots long) can represent cationic Al3+. The oxide ion, O2−, can be represented by a red 1 × 2 brick (1 dot wide and 2 dots long) (Figure 1). These two types of bricks can then be assembled to make a product that helps students determine the cation-to-anion ratio in aluminum oxide and write the chemical formula.
Materials
This is just one example. Mega Bloks.
References
JCE Classroom Activity #113: An Interlocking Building Block Activity in Writing Formulas of Ionic Compounds, Kristie R. Ruddick and Abby L. Parrill, J. Chem. Educ. 2012, 89, 11, 1436–1438, 9/19/2012
https://doi.org/10.1021/ed200513y
Related
Teaching chemistry with LEGO bricks
Ryo Horikoshi, Chemistry Teacher International, 12/21/2020
“Since LEGO bricks possess varieties of shapes and colors, they can be employed to design various teaching aids, including periodic tables, molecular models, polymer structure models, and frameworks for handmade measuring instruments. The polymeric structure models are generally difficult to build with typical ball-and-stick type molecular models; however, they can be easily built, employing LEGO bricks.”
DOI: https://doi.org/10.1515/cti-2020-0017
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What is genetic material?
What is genetic material? What are genes for?
Look closely inside any living creature – plants, animals, even fungi.
If you use a microscope you can see individual cells.
Looking even more closely you can see that cells have a nucleus
Look even more closely inside the nucleus and you’ll see chromosomes.
(Here the nucleus has been punctured, and chromosomes are spilling out.)
Now if you look with some super sophisticated techniques then you’ll see that these chromosome aren’t solid.
They seem to be made of a kind of thread, something really thin that is wrapped up to make a shape.
Looking even close, this thread is made up of molecules bonded together into a kind of helix (spiral shape.)
Not just that, but two spiral shapes wrapped around each other – a double helix
This beautiful molecule here is DNA.
The DNA wraps itself up to make those chromosomes.
Why is it here? This contains the instructions of life itself.
DNA contains all of the information necessary to build a living thing.
Each separate piece of DNA – each gene – builds a different part of the organism.
So we call this genetic material.
There’s another important type of genetic material, RNA
In most forms of life DNA is the “original copy”, the master blueprint.
Cells work by making a working copy of the blueprint.
This copy is made of mRNA (messenger RNA) molecules.
That RNA then leaves the nucleus (see above animation) and gets used by the cell to build things.
So both DNA and RNA are types of genetic information.
Genetic info in viruses
Although viruses are not alive in the same way that cells are, they also have genetic material.
Some viruses have DNA, others have RNA.
The basic idea is still the same. The DNA, or RNA, in a virus is the instruction set to build more virus particles.
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Beyond immediate death count: Long Covid and blood clots: Covid-19 as a blood clot disease
Coronavirus disease 2019 (COVID-19 ) is caused by a virus. Its name is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2.) This is one of a number of respiratory viruses.
Myth: Covid only affects the lungs. And only about 0.5% of infected people get sick and die, so the rest of us will be okay.
Fact: Covid-19 is an endothelial blood clot disease as well as a pulmonary disease. Blood clots travel to all other organs in the body, including the brain, and can cause serious damage even in survivors. People are at least ten times more likely to get blood clots issues and neurological issues,than dying.
Many covid-19 survivors report painful and debilitating symptoms. Some report feeling like they were being suffocated. During these episodes their blood oxygen levels drop, which causes biochemical stress in many organs.
The death rate alone is staggeringly higher than what we normally see from influenza.
A death rate of .5% is higher than any other viral pandemic that has hit the United States since the Spanish flu, the 1918 flu pandemic. The United States of America has a population of over three hundred million people. Over eight hundred thousand Americans have already died due to this disease. If left unchecked, Covid-19 would kill millions Americans.
Deaths are just a small part of the coronavirus story: Covid-19 is an endothelial blood clot disease.
Many covid-19 patients have blood clots in the legs, lungs, and cerebral arteries leading to the brain. Likely in other locations as well.
Above image: formation of an occlusive thrombus in a vein.
Take blood clots seriously
Blood clots are no joke. They may lead to.
* strokes
* encephalitis (swelling of the brain)
* heart attacks
* inflammation of the heart
* deep vein thromboses in the legs
* clots in the lungs
* stroke-causing clots in cerebral arteries.
* pain, shortness of breath
* fatigue, dizziness due to lack of oxygen to the brain
* kidney failure
* degradation of kidney dialysis: clots can clog kidney dialysis machines.
Doctors have documented short term neurological damage in covid patients, even in some otherwise asymptomatic people.
It is likely that there is long-term neurological damage as well.
“If you start to put all of the data together that’s emerging, it turns out that this virus is probably a vasculotropic virus, meaning that it affects the [blood vessels],”
In a paper published in April in the scientific journal The Lancet, Mehra and a team of scientists discovered that the SARS-CoV-2 virus can infect the endothelial cells that line the inside of blood vessels.
Endothelial cells protect the cardiovascular system, and they release proteins that influence everything from blood clotting to the immune response. In the paper, the scientists showed damage to endothelial cells in the lungs, heart, kidneys, liver, and intestines in people with Covid-19.
– Covid-19 May Be a Blood Vessel Disease, Dana G. Smith
How covid-19 attacks the brain
John Hamilton writes
Many patients who are hospitalized for COVID-19 are discharged with symptoms such as those associated with a brain injury….
COVID-19 also appears to produce many other brain-related symptoms ranging from seizures to psychosis, a team reports in the Jan. 5 issue of the journal Alzheimer’s & Dementia…. it may even increase a person’s risk of developing Alzheimer’s disease.
For many affected patients, brain function improves as they recover. But some are likely to face long-term disability, de Erausquin says.
… “What we found was that the very small blood vessels in the brain were leaking,” Nath says. “And it wasn’t evenly — you would find a small blood vessel here and a small blood vessel there.” The injuries resembled those from a series of tiny strokes occurring in many different areas of the brain, Nath says.
How COVID-19 Attacks The Brain And May Cause Lasting Damage, Jon Hamilton
Conclusions
Many covid-19 survivors may die many years or decades earlier than they otherwise would have, due to the blood clots and endothelial damage.
The full death toll of Covid-19 will likely be many times higher than the current toll. As 1/2022 over 839,000 Americans have died. It is certain that that over the coming years and decades many more people will die from their covid-19 damage. As such, we should be diligent in protecting ourselves, our loved ones, and everyone in our communities.
How to protect ourselves
Gather knowledge, e.g. Covid 19 is an airborne virus
Wearing masks in certain situations – Unmasking mask myths
Note that vaccinated people can be protected yet still transmit covid-19.
Social distancing
Washing hands
Zinc supplements and coronaviruses, rhinoviruses, common cold
Getting a covid-19 vaccination
Covid-19 Vaccine Tracker, Bloomberg
High effectiveness of covid-19 vaccines, breakthrough cases and the base rate fallacy
References
High effectiveness of covid-19 vaccines, breakthrough cases and the base rate fallacy
What Does COVID Do to Your Blood? John Hopkins Medicine, Panagis Galiatsatos, M.D., M.H.S. and Robert Brodsky, M.D.
Covid-19 May Be a Blood Vessel Disease, Which Explains Everything, Dana G. Smith, Elemental, 5/29/2020
How COVID-19 Attacks The Brain And May Cause Lasting Damage, Jon Hamilton, Shots: NPR Health News, 1/5/2021
Microvascular Injury in the Brains of Patients with Covid-19 Letters, New England Journal of Medicine, Myoung-Hwa Lee et al, DOI: 10.1056/NEJMc2033369
The chronic neuropsychiatric sequelae of COVID‐19: The need for a prospective study of viral impact on brain functioning, Gabriel A. de Erausquin et al, Alzheimer’s & Dementia [journal,] 1/5/2021, https://doi.org/10.1002/alz.12255
Our Covid-19 articles
Respiratory viruses (influenza, rhinoviruses, coronaviruses etc)
How do viruses spread? Airborne vs non-airborne
Beyond immediate death count: Long Covid and blood clots: Covid-19 as a blood clot disease
High effectiveness of covid-19 vaccines, breakthrough cases and the base rate fallacy
How vaccinated people can be protected yet still transmit covid-19
Vaccines – what does 95% efficacy actually mean?
Simple DIY masks could help flatten the curve. We should all wear them in public.
Unmasking mask myths
How does the Schrodinger equation create orbitals?
How does the Schrödinger equation (from quantum mechanics) create atomic orbitals and molecular orbitals that?
Where do these beautiful three dimensional shapes come from?
Why do they have the shapes that they do?
This lesson assumes that you have already learned about –
waves and superposition
constructive and destructive interference
the classical models of the atom
Neils Bohr and his semi-quantum mechanical model of the atom
the Schrödinger model of the atom
Physicists use the Schrödinger equation to model an e- around a nucleus.
Hence, e- = electron
Let’s first review the idea of superposition: Notice what happens here when two waves pass through the same space, at the same time.
The waves are not bouncing off of each other – they pass through each other.
Waves can add together – constructive interference. That’s what we see here.
Below we see two waves that add together to create a region where they cancel out. This is destructive interference.
Can we make waves appear to stand still? Consider what happens when two waves come at each other, at just the right speed and height:
A standing wave is produced!
We see this in music all the time. Pluck a string on a guitar or violin.
Musicians call the first standing wave the fundamental, or first harmonic.
Higher frequency standing waves are called overtones.
This violin string isn’t quite showing a standing wave, but it gets close.
We can get standing wave on any physical object, like on a cymbal, or on any flat round disk.
Your loudspeakers, on a stereo system or in earbuds, move like this.
Well, in the Schrödinger equation:
Constructive interference leads to regions where we’re more likely to find the e-.
Destructive interference leads to regions where we’re less likely to find the e-.
Here we model an electron as a standing wave around the nucleus of an atom. Compare the left and right side.
On the left a standing wave is produced, when the wavelength is of such a length that it creates constructive interference. On the right the wavelength has a different length, and no constructive behavior develops.
Allowed Not allowed
This is what happens in atoms – e- aren’t solid objects.
Instead, e- are understood to be quantum phenomenon that follow a wave equation!
When the wavelength of the e- allows for constructive interference, that is where it has an effect.
Of course, that model for e- around an atom is too simple. It is flat.
So let’s show a standing wave in three dimensions.
How do these equations lead to the spherical “s” orbitals?
This next image is from 6.3 Development of quantum theory
Here scientists use the Schrödinger equation to model an e- as standing waves in three dimensions.
from Opentextbc.ca, Chapter 6. Electronic Structure and Periodic Properties of Elements
What would it look like inside these spheres?
Below is a “traveling wave resulting from a point source emitting symmetrically in 3 dimensions producing spherical wavefronts.”
One of the upper quadrants of the region has been removed in order to expose the internal structure of the wave”
from intothecontinuum.tumblr.com
Just like the 2D case we can also create a ‘”standing wave resulting from an outward and inward traveling wave”
from intothecontinuum.tumblr.com
Now that we have made it here, here is a chapter on electron orbitals from ChemPRIME (Moore et al.)
This chapter is great for honors or AP physics or chemistry students.
Creating d and f orbitals
The same general idea is true for how d orbitals and f orbitals appear.
There are many possibilities for the wave function of an e- with a higher amount of energy.
We add all of them together – this is superposition.
Most of those waves cancel each other out (destructive interference.)
Whatever remains is there and assumes a certain shape (constructive interference.)
Here is a simplified version – different wave possibilities adding together to create a d orbital.
Molecular orbitals
Hybrid orbitals, what we see in molecules, are more complex examples of the same idea:
We see wave functions interfering with each other.
When two orbitals overlap we get more complex forms of interference, leading to new shapes.
Here, a hydrogen atom 1s orbital bonds with another Hydrogen atom 1s orbital.
This creates a H2 molecule with a sigma orbital (σ).
https://www.grandinetti.org/molecular-orbital-theory
This is a representation of two oxygen atoms merging into an O2 molecule in the singlet state.
This shows the most accurate representation for the actual shape of the molecule.
The original 2s and 2p atomic orbitals can be seen merging to create Sigma and Pi orbitals, which bind the atoms together.
The 1s orbitals do not combine and still show the individual atoms.
This GIF is from Wikimedia Commons, O2 MolecularOrbitals Anim.gif
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.
Teaching quantum mechanics in high school
I would love to hear how science teachers are teaching quantum mechanics in high school. Many of us plan to have a week long sequence in Honors Physics, or AP Physics, or perhaps in a science elective.
This could even be done in regular college-prep level physics classes if the students are so motivated. Having discussions like these – even done totally qualitatively, without math, are hallmarks of an inspiring science classroom.
I’m putting together here my resources on teaching various aspects of quantum mechanics, in what seems to be a reasonable order. Please understand that this is not an online textbook. These articles were each developed separately, so there is a lot of overlap.
Also, there is no mathematics, calculus, or differential equations required.
The nature of reality itself! The allegory of the cave
The wave nature of matter
Why did we have to develop modern physics? What is wrong with just keeping classical physics?
Early quantum theory
Schrodinger model of the atom
Schrodingers cat
Articles about the consequences of quantum mechanics
What are covalent bonds between atoms?
The normal force: So, objects really never touch?
How time and space could be a quantum error correcting code
The origins of space and time
Quantum teleportation (and it isn’t what you think)
Time’s arrow may be traced to quantum source
The quantum thermodynamics revolution
The four possible types of multiverses
Parallel universes in quantum mechanics
Karpman’s drama triangle
Practical psychology – Thoughts on Karpman’s drama triangle, narcissistic personality disorder, and finding an alternative – the empowerment triangle.
This phenomenon can occur in dysfunctional family or community dynamics; it is especially prevalent in social media arguments. This model explains much of the psychology behind virtue signaling and moral grandstanding.
Karpman’s drama triangle is a tool used in psychotherapy, specifically transactional analysis. Once a person’s role in this dynamic is realized, people can develop skills that create a healthier and more productive dynamic, e.g. the empowerment triangle.
Let’s look at the drama triangle in action:
This next section excerpted from TED: The Empowerment Dynamic
The Rescuer – looks for victims, businesses or causes to save and are quick to jump-in and save the day, even when others are responsible. Rescuers believe they will be appreciated and valued for their good deeds. They feed off of crisis’ so they can be needed and valued for their help.
The Persecutor – is controlling, blaming, critical, oppressive, authoritarian, rigid… Persecutors believe they must win and convince others that they are right. They have little compassion for another’s perspective or way of doing things.
The Victim – feels powerless and at the mercy of life’s events. Avoids taking responsibility for their actions, finding it easier to blame others or their circumstances. Suffering is a perpetual state for victims. Self-pity. Interestingly, these feelings then create an odd state of entitlement and specialness.
Lynne Forest writes:
“Each person has a primary or most familiar role – what I call their “starting gate” position. This is the place from which we generally enter, or “get hooked” onto, the triangle. We first learn our starting gate position in our family of origin.
Although we each have a role with which we most identify, once we’re on the triangle, we automatically rotate through all the positions, going completely around the triangle, sometimes in a matter of minutes, or even seconds, many times every day.”
Why do people fall into the drama triangle?
Behaviors in the drama triangle, while dysfunctional, are highly seductive.
The persecutor gets to feel powerful.
The victim gets pity, and a pass from responsibility.
The rescuer feels like a saviour; they perceive themselves to have moral superiority. They feel that only they can rescue the victim. Ironically, rescuers themselves can become persecutors of those they address if others do not accept the rescuer’s demands to be seen as saviour.
Ironically the rescuer does not really help the victim. In fact they often can keep the victim in place by promoting the victimhood narrative.
Victims only break out of this dynamic by rejecting powerless. One needs to reclaim personal agency and accountability. One needs to develop allies of equals, not rescuers who manipulate. By doing so then the former victim takes power away from the persecutor – they no longer needs the rescuer.
Image created by Robert Kaiser
What the Drama Triangle has in common with narcissistic personality disorder
Sarah Davies writes
This drama triangle is a dynamic often seen with narcissists and is what relentlessly plays out in relationships of narcissistic abuse and other toxic relationships.
The ‘victim’ position is the “poor me” stance. The person in this position sees themselves as being victimized, bullied, being hard done by, helpless, hopeless, persecuted or oppressed.
The Persecutor: The persecutor is often the bully narcissist on the attack. This is the position of blaming, shaming, controlling, being aggressive, oppressive, judgmental or authoritative, threatening and/or arrogant.
The Rescuer: The rescuer is often the classic codependent, echoist, enabler, fixer and/or helper. The rescuer tends to respond to the real or portrayed ‘helplessness’ of the victim. The person in the rescue position will assume responsibility on the ‘victims’ behalf….
The rescuer will take on responsibility for situations or issues that are not theirs…. the narcissist shifts quite skillfully between any one of these positions… they can use the position of rescuer to control and manipulate.
Moving to the empowerment triangle
Ideally people will want to transition from the drama triangle model to an empowerment triangle model. This happens when people recognize that their previous dynamic was not working, and they become willing to learning new ways to talk with others. When we do so, we develop new skills, as shown in this table:
Let’s see what this change looks like:
Image created by Robert Kaiser
Resources
Karpman drama triangle
What does narcissism have in common with Karpman’s drama triangle?
Escaping Conflict and the Karpman Drama Triangle. BPD Family, Borderline personality disorder website
Moral grandstanding: there’s a lot of it about, all of it bad By Justin Tosi and Brandon Warmke
Books
The Power of TED* (*The Empowerment Dynamic) by David Emerald
Articles
Narcissism, Personal Accountability, & Social Justice, Ava Pommerenk, Medium, 11/23/2018
Narcissists, Psychopaths, and Manipulators Are More Likely To Engage in ‘Virtuous Victim Signaling,‘ Says Study. Elizabeth Nolan Brown, Reason, 7/7/2020
Ok, E., Qian, Y., Strejcek, B., & Aquino, K. (2020, July 2). Signaling Virtuous Victimhood as Indicators of Dark Triad Personalities, Journal of Personality and Social Psychology, http://dx.doi.org/10.1037/pspp0000329
Lynne Forest, The Three Faces of Victim – An Overview of the Victim Triangle
Narcissistic Abuse & the Drama Triangle, excerpt from Never Again – Moving On from Narcissistic Abuse and Other Toxic Relationships, Sarah Davies, 2019, Matador
‘Why Me?’ The Role of Perceived Victimhood in American Politics. Miles T. Armaly & Adam M. Enders, Political Behavior (2021). https://doi.org/10.1007/s11109-020-09662-x
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Zinc supplements and coronaviruses, rhinoviruses, common cold
There is reason to believe that taking over-the-counter Zinc supplements can reduce the severity and duration of infection by respiratory viruses such as coronavirus.
Warning: Like all nutritional and dietary supplement studies, this is a notoriously difficult topic to research, because there’s no way for researchers to be certain of exactly what people do or don’t eat during the period of the study.
Biochemistry
In what forms does Zinc exists in our gut, after digestion, and before absorption:
As the Zinc (II) ion – Zn2+
In what form does Zinc exist in our bloodstream and in our cells?
Same as above – Zn2+
Do we normally need to take zinc supplements?
No. Severe zinc deficiency is rare, usually caused by an inherited condition.
We usually don’t see people deficient in zinc unless they have either a malabsorption syndromes or chronic alcoholism.
The recommended dietary allowance (RDA) for adult men is 11 mg/day; for adult women 8 mg/day of zinc.
For those who do take high doze zinc supplements for a long time (UL; 40 mg/day for adults) we should watch our copper levels. Long term use of higher dose zinc can result in copper deficiency
Zinc dietary supplements
Some doctors recommend taking zinc supplements when one feels the onset of cold, influenza, or covid symptoms.
It is often sold as Zinc gluconate (the zinc salt of gluconic acid.)
This is an ionic compound consisting of two anions of gluconate for each zinc(II) cation.
Zinc gluconate is a popular form for the delivery of zinc as a dietary supplement.
– Zinc and the common cold, Wikipedia
Evidence for using Zinc to treat coronaviruses and rhinoviruses
Many doctors advocate taking zinc lozenges within one day of the onset of symptoms of a cold, coronavirus, or rhinovirus.
Always check with your doctor first; some suggest taking a Zinc supplement every 3 hours (during waking hours) until you feel better.
The following section has been excerpted from Zinc, Linus Pauling Institute, Micronutrient Information Center, Oregon State University.
A 2013 Cochrane review confirmed that oral zinc administrated within 24 hours of symptom onset could reduce the duration of cold symptoms (14 trials, 1,656 participants)
– Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2013(6)
Oral zinc was effective regardless of the age of participants (children or adults) and the type of zinc formulation (gluconate/acetate lozenges or sulfate syrup).
Beneficial effects on cold duration were seen in trials that provided more than 75 mg/day of zinc but not in trials that used lower doses.
The pooled analysis of five trials found no evidence of an effect of oral zinc on the severity of cold symptoms.
The analysis of secondary trial outcomes suggested a faster resolution of specific cold symptoms (cough, nasal congestion, nasal drainage, sore throat) and a lower proportion of participants exhibiting cold symptoms after seven days of treatment in zinc- versus placebo-supplemented participants.
– Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2013(6)
With numerous well-controlled trials and meta-analyses, the efficacy of zinc lozenges or syrup in treating common cold symptoms is no longer questionable.
A meta-analysis of seven trials recently reported a 33% reduction in the duration of cold symptoms with the intake of zinc lozenges (>75 mg/day of elemental zinc)
– Hemila H. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open. 2017;8(5)
However, many supplemental zinc formulations available over-the-counter have been found to release zero zinc ions (i.e., the biologically active form of zinc) or to contain additives (e.g., magnesium, certain amino acids, citric acid) that either cancel out the benefit of zinc or worsen cold symptoms.
– Eby GA, 3rd. Zinc lozenges as cure for the common cold–a review and hypothesis. Med Hypotheses. 2010;74(3):482-492
Although taking zinc lozenges for a cold every two to three hours while awake will result in daily zinc intakes well above the tolerable upper intake level (UL) of 40 mg/day for adults, the use of zinc at daily doses of 50 to 180 mg for one to two weeks has not resulted in serious side effects.
– Eby GA, 3rd. Zinc lozenges as cure for the common cold–a review and hypothesis. Med Hypotheses. 2010; 74(3):482-492
Do not use zinc supplements for long periods of time (6 or more weeks) unless under a doctor’s orders. Long term use could result in copper deficiency.
What about Zinc nasal sprays?
Intranasal zinc preparations: pooled analysis … showed no overall benefit of intranasal zinc on the risk of still experiencing cold symptoms by day 3.
– D’Cruze H, Arroll B, Kenealy T. Is intranasal zinc effective and safe for the common cold? A systematic review and meta-analysis. J Prim Health Care. 2009;1(2):134-139.
Of serious concern are several case reports of individuals experiencing loss of the sense of smell (anosmia) after using intranasal zinc as a cold remedy.
Since zinc-associated anosmia may be irreversible, most doctors hold that intranasal zinc preparations should be avoided.
References
A Guide to Human Zinc Absorption: General Overview and Recent Advances of In Vitro Intestinal Models (great graphics) by Maria Maares and Hajo Haase , Nutrients 2020, 12(3), 762; https://doi.org/10.3390/nu12030762
https://www.mdpi.com/2072-6643/12/3/762/htm
Frederickson, C.J.; Koh, J.Y.; Bush, A.I. The neurobiology of zinc in health and disease.
Nat. Rev. Neurosci. 2005, 6, 449–462 https://www.nature.com/articles/nrn1671
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How do batteries work?
How do batteries work?
Let’s start by looking inside one, and seeing the flow of electrical charges.
Chemical reactions occur within battery.
e- are stripped away from the carbon electrode.
e- try to flow from – terminal to + terminal, if a conducting circuit exists.
Here’s an amazing explanation: How A Battery Works by John Denker at Av8n.com
Relationship between battery and voltage
Voltage sources
Water doesn’t flow by itself unless going downhill
Hills create a drop.
Charge doesn’t flow by itself unless going “down voltage”, i.e. down a change in “potential difference”.
Batteries or generators create a potential difference.
.
Oxymoron alert! Batteries do not provide “charge”
Batteries may run out of something, sure but they certainly don’t run out of electrical charges.
Technically speaking, they can’t be charged or re-charged?!
The total amount of charged particles in a battery is always the same.
Let’s think this through: The charges in batteries (and wires!) are electrons. We’ll abbreviate them as e-.
e- are already in the battery, wire, etc.
Batteries merely provide the voltage (“pressure”) to move the e-
When e- flow out of one end, new e- come into the other end.
So what is it that batteries lose over time? They lose ENERGY.
Batteries are powered by chemical reactions.
So over time batteries lose chemical potential energy.
When you “recharge” a battery, you’re using electricity to alter the battery’s chemistry.
You’re taking electrical energy and storing that in chemical bonds in molecules, within the battery.
So you don’t give batteries more charge: you give it more energy.
Apps
Students use that wheel at the bottom to control the animation playback. It lets them play it at the speed they want and reverse it anywhere they need to to understand what is happening.
How does a lithium battery work in an electric car?
PhET battery voltage app
PhET battery resistor circuit
HONORS
What is going on with electromagnetic fields inside a battery?
In Physics forums we find these details.
Contributor leright writes:
Inside the battery, the negative charges flow IN THE DIRECTION OF THE E-FIELD, which means the negative charges are going AGAINST the electrostatic force set up inside the battery.
The electrons are able to flow against the electrostatic force because of an opposing chemical potential.
Normally, a battery which is not shorted out or connected to a load is under equilibrium conditions, meaning the chemical potential inside the battery exactly equals the electrical potential. Under these conditions, no charge carriers flow.
If you connect the positive terminal of the battery to the negative terminal, through some load, the electrons at the negative terminal of the battery flow through the wire to the positive terminal by the electric field set up by the E-field external to the battery.
When these electrons reach the positive terminal, the E-field inside the battery is momentarily reduced which in turn upsets the equilibrium between the chemical and electrical potential.
The chemical potential then dominates and allows the negative charge to continue flowing from positive terminal to negative terminal until equilibrium is once again established.
Notice that the electrons flow AGAINST the coulomb force inside the battery. They are able to do this because of the chemical potential, which is slightly greater than the electrical potential when equilibrium is disturbed.
Contributor Vanesch adds:
The whole point is that the flow of electrons (and ions) is not controlled by the electrostatic potential, but by the ELECTROCHEMICAL potential.
That electrochemical potential is also function of the concentrations of chemicals and a battery is exactly such a structure, where the gradient in electrochemical potential and the gradient in electrostatic potential are in opposite directions.
Hence, it is the electrochemical potential which drives electrons and ions against the electrostatic force.
Of course, the electrostatic potential is a PART of the electrochemical potential. So it is true that the electrostatic force tends to diminish the tendency to flow against the E-field, but if the concentration gradients can overcome this, then nevertheless, the charges flow against the electrostatic force.
The price to pay is that this flow will change the concentrations of chemicals in exactly the way which is necessary to “drop” the gradient of the electrochemical potential.
The system reaches a static condition when the electrochemical potential is equal everywhere: in that case, charges are not “motivated” to move anymore.
This situation can STILL contain both a gradient in electrostatic potential and a gradient in concentrations.
This is BTW, what happens in a PN junction in a semiconductor. There, you DO have an E-field, and NO charges flowing (because they are pushed exactly the same amount in the opposite direction by the concentration gradient, and both cancel).
E-field-inside-of-a-battery: Physics Forums
Learning Standards
Massachusetts 2016 Science and Technology/Engineering (STE) Standards
HS-PS2-9(MA). Evaluate simple series and parallel circuits to predict changes to voltage, current, or resistance when simple changes are made to a circuit
HS-PS3-1. Use algebraic expressions and the principle of energy conservation to calculate the change in energy of one component of a system… Identify any transformations from one form of energy to another, including thermal, kinetic, gravitational, magnetic, or electrical energy. {voltage drops shown as an analogy to water pressure drops.}
HS-PS3-2. Develop and use a model to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles and objects or energy stored in fields [e.g. electric fields.]
HS-PS3-3. Design and evaluate a device that works within given constraints to convert one form of energy into another form of energy.{e.g. chemical energy in battery used to create KE of electrons flowing in a circuit, used to create light and heat from a bulb, or charging a capacitor.}
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Why teachers are skeptical about standardized tests
Why are many teachers skeptical about standardized tests? Why do many parents and teachers wants us to reduce our reliance on mandatory high stakes testing, like the Massachusetts MCAS exam, New York Regents exam, Texas STAAR, etc.? Why not just continue to insist on them?
In response to questions like these, Jeff Bigler writes
Often, that kind of sentiment comes from districts where students perform well on the tests. The problem with the tests is that they end up increasing the very achievement gap that they’re purported to reduce. Let me start with an example:
This is a story about three AP teachers. Granted, AP is not the same as MCAS, but it is also a high-stakes (at least for college-bound students) standardized test.
The first teacher is from a wealthy district. That teacher’s students all earned scores of 4 & 5.
The second teacher is from a middle middle class district. One-third of the second teacher’s students earned passing scores (3 or higher). None of that teacher’s students received a 5 (over a three-year period).
The third teacher is from an economically disadvantaged district. Only about 1% of that teacher’s students earned passing scores.
If you’re like most people, you would conclude that the first teacher is the best of the three, and the third is the worst, and that the best course of action is to fire the third teacher and incentivize the first teacher to teach in the third school.
However, all three of those teachers are the same person: me. Moreover, I taught in the wealthy district (Belmont) first, the middle middle class district second (Waltham), and the economically depressed district third (Lynn).
If anything, because of having more experience, I am a better teacher in Lynn than I was in either Belmont or Waltham. Those students in Lynn are getting the benefits of a teacher from a wealthy district whose students successfully earned high scores—those same benefits that are supposed to magically transform them into high-achieving scholars instantaneously.
What happened? Nothing. The students in Belmont were academically superior because their families made sure to educate them from the time they were babies. It’s like compound interest—students who have more academic capital invested from an earlier date get more returns. I could have stood in front of the Belmont kids picking my nose for 180 days and they would have done just as well, either on their own or because their parents would have hired tutors.
The kids from Lynn may have been well cared for in daycare, but for most of them, education didn’t really start until kindergarten. Both of their parents worked. (And in many cases, their parents spoke no English and never went to high school.) Many of my students have to figure out everything for themselves with no help other than from their teachers, and often while caring for younger siblings and sometimes even for their parents.
Now back to MCAS. In the 1990s, when Massachusetts created the standards that MCAS would be based on, they looked at the average developmental level of students across the state, and made that the minimum.
This means fully half of the children (the ones who were below average) were now being required to perform at a level beyond their developmental level. Of course, the averages are statewide; more of the children in poorer communities are being required to work beyond their developmental level than in wealthier communities.
When students are required to “learn” something before they are developmentally ready (because it’s on MCAS, and schools are punished based on MCAS scores), all their teachers can do is teach them procedures that generate the right answers. So the children dutifully learn those procedures.
They get the right answers, but those procedures can’t really be used as building blocks, and the students forget them shortly after learning them. So everything needs to be reviewed every year, and students are not learning in a way that they retain long-term.
This problem compounds itself every year. By the time they get to my physics class in 11th and 12th grade, many of my students can’t do basic Algebra 1 problems even though they had to pass Algebra 2 in order to take my class.
Children from economically depressed areas are also much more likely to form strong attachments to their teachers. The ones who live in abusive homes often develop a high level of empathy – it’s a coping mechanism that helps them protect themselves by sensing when it’s time to hide.
Those children have a heightened sense of their teachers’ stress about the test, and they worry that if they fail, they will be the cause of the one stable adult in their life getting fired.
Small wonder that those kids are so anxious that they throw up on the tests or take dangerous levels of ADHD medications—in their minds they are performing heroic actions to save their teachers. I cling to the vain hope that one day we will have a commissioner of education who understands child development and is trauma-informed. But I’m not going to hold my breath.
Related articles
Here’s a great example: Sara Holbrook, a poet, found that even she couldn’t even answer questions about her own work on a Texas state standardized exam because the questions are so poorly conceived. Valerie Strauss 1/7/2017, The Washington Post,
Poet : I can’t answer questions on Texas standardized tests about my own poems
I Can’t Answer These Texas Standardized Test Questions About My Own Poems
Standardized Testing Misses The Mark When It Comes To Student’s Cognitive Competency. The truth is, learning, insight, intellectual development are not quantifiable. By George Popham, Bay State Learning Center
Standardized Testing Misses The Mark When It Comes To Student’s Cognitive Competency
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Helium cycle
On Earth, the production of new helium is result of radioactive decay.
Helium is found in large amounts in minerals of uranium and thorium.
About 3,000 metric tons of helium are generated per year throughout the lithosphere.
Earth’s crust [He] =8 parts per billion
Seawater [He] = 4 parts per trillion.
Earth may gain He atoms from outer space, from cosmic rays
Most He in Earth’s atmosphere escapes into space by several processes.
Near Earth’s surface, the average KE of He atoms is not enough for them to escape Earth’s gravitational field.
In the exosphere, He atoms have a greater KE, so some do escape.
Much 3He leaves Earth in this way. Some 4He leaves in this way.
Some He undergoes photoionization by the polar wind. This then escapes along open lines of the Earth’s magnetic field.
Some He goes into space due to direct interaction of the solar wind with the upper atmosphere.
This occurs during the short periods of lower magnetic-field intensity while the Earth’s magnetic field is reversing.
talkorigins.org Helium gas discussion
Learning Standards
Next Generation Science Standards
HS-LS2-4. Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.
A Framework for K-12 Science Education Practices, Crosscutting Concepts, and Core Ideas (2012)
LS2.B: Cycles of Matter and Energy Transfer in Ecosystems
College Board Standards for College Success: Science
Standard ES.4 – Cycles of Matter and Energy: Matter on Earth is finite and moves through various cycles that are driven by the transformation of energy
LS.4.1 Matter Cycling – Students understand that matter is continuously recycled within the biological system and between the biological (biotic) and physical (abiotic) components of an ecosystem.
ESH-PE.4.2.2 Construct a graphical representation of the global carbon cycle (or the cycle of some other element or molecule), and use this representation to predict the effects of some environmental change (e.g., evolution of life, tectonic change, human activity) on carbon cycling (or the cycling of some other element or molecule).
Enduring Understanding 3A – Biogeochemical cycles are representations of the transport, transformation and storage of elements on a local, regional or global scale.
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Thanks for reading. While you’re here see our other articles on astronomy, biology, chemistry, Earth science, mathematics, physics, the scientific method, and making science connections through books, TV and movies.
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