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The physics of space elevators

What are we learning?

Engineering is the use of physics to design buildings, tools, vehicles, or related infrastructure.  We’ll examine real world engineering projects – and see how these techniques may be extended to proposed mega-engineering projects.

Why are we learning this? We address Science and Engineering Practices in the NGSS

  • Ask questions that arise from examining models or a theory, to clarify and/or seek additional information and relationships.

  • 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 and/or evaluate questions that challenge the premise(s) of an argument, the interpretation of a data set, or the suitability of the design

– Science and engineering practices: NSTA National Science Teacher Association

– Next Generation Science Standards Appendix F: Science and Engineering Practices

space elevator is a proposed type of space transportation system. The main component would be a cable (also called a tether) anchored to the surface and extending into space.

The design would permit vehicles to travel along the cable from a planetary surface, such as the Earth’s, directly into space or orbit, without the use of large rockets.

An Earth-based space elevator would consist of a cable with one end attached to the surface near the equator and the other end in space beyond geostationary orbit (35,800 km altitude).

The competing forces of gravity, which is stronger at the lower end, and the outward/upward centrifugal force, which is stronger at the upper end, would result in the cable being held up, under tension, and stationary over a single position on Earth.

This introduction has been fro Space elevator article (Wikipedia)

Video – NOVA Science Now 

NOVA Science Now Space elevator – 11 minutes

Youtube. NOVA scienceNOW : 29 – Space Elevator

Pre-viewing: learn these vocabulary terms

  1. geosynchronous orbit

  2. prototype:

  3. buckyball:

  4. carbon nanotubes:

  5. What are the arrangements of carbon atoms in: Diamonds, coal, graphite

Size and scale

The carbon nanotube space elevator would transport materials into geosynchronous orbit around Earth.

How does the distance of this geosynchronous orbit compare to the distance of space explored by a space shuttle?

Give students the size and distance stats below and have them calculate, and then show, the scale of the two orbits.

We may ask students use sheets of paper to make models showing the scale. Once can place the sheets side by side for comparison.

Size and Distance Stats

Earth is represented by a 10″ globe (or use whatever size globe you have)

actual diameter of Earth = 8,000 miles

space shuttle orbit = use an orbit of 200 miles above surface of Earth

(The space shuttle’s orbit ranges from 115 to 250 miles.)

geosynchronous satellite orbit = 22,000 miles above surface of Earth

Questions for after viewing

In building a space elevator:

7. Which of these components/materials would be the most difficult to obtain?

8. Which are readily available?

9. How long are the longest carbon nanotubes made so far?

10. What are some of the other challenges we would encounter in building this?

(Note 2 – and also briefly note possible solutions. See the endcard, below.)

A basic space elevator

Carbon nanotubes are one of the best candidates for a material strong enough to create a space elevator.

carbon nanotubes

http://www.pbs.org/wgbh/nova/space/space-elevator.html

Analyzing a space elevator with a simple free-body diagram

Illustration of the Coriolis force

AP Physics Space Elevator analysis

Additional video resources

Engineering challenges lie ahead

From NOVA Science Now

Specific engineering challenges

TV episodes & videos

Extreme Engineering: Space Elevators

NOVA scienceNOW : 29 – Space Elevator

Physics of Making and Breaking Space Elevators – Science of the Foundation

Space Elevator – Science Fiction or the Future of Mankind?

Articles

Space elevators in fiction

What could go wrong?

What Happens If a Space Elevator Breaks? By Rhett Allain

In the first episode of the Foundation series on Apple TV, we see a terrorist try to destroy the space elevator used by the Galactic Empire. This seems like a great chance to talk about the physics of space elevators and to consider what would happen if one exploded. (Hint: It wouldn’t be good.)

People like to put stuff beyond the Earth’s atmosphere: It allows us to have weather satellites, a space station, GPS satellites, and even the James Webb Space Telescope. But right now, our only option for getting stuff into space is to strap it to a controlled chemical explosion that we usually call “a rocket.”

Also see If a space elevator collapsed, how much damage would it do to people and property?

Learning Standards

NGSS

Ask questions that arise from examining models or a theory, to clarify and/or seek additional information and relationships.

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 and/or evaluate questions that challenge the premise(s) of an argument, the interpretation of a data set, or the suitability of the design

– Science and engineering practices: NSTA National Science Teacher Association

– Next Generation Science Standards Appendix F: Science and Engineering Practices

Massachusetts Science and Technology/Engineering Curriculum Framework

HS-PS2-1. Analyze data to support the claim that Newton’s second law of motion is a mathematical model describing change in motion (the acceleration) of objects when acted on by a net force.

HS-PS2-10(MA). Use free-body force diagrams, algebraic expressions, and Newton’s laws of motion to predict changes to velocity and acceleration for an object moving in one dimension in various situations

Massachusetts High School Technology/Engineering

HS-ETS1-1. Analyze a major global challenge to specify a design problem that can be improved. Determine necessary qualitative and quantitative criteria and constraints for solutions, including any requirements set by society.

HS-ETS1-2. Break a complex real-world problem into smaller, more manageable problems that each can be solved using scientific and engineering principles.

HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, aesthetics, and maintenance, as well as social, cultural, and environmental impacts.

HS-ETS1-4. Use a computer simulation to model the impact of a proposed solution to a complex real-world problem that has numerous criteria and constraints on the interactions within and between systems relevant to the problem.

HS-ETS1-5(MA). Plan a prototype or design solution using orthographic projections and isometric drawings, using proper scales and proportions.

HS-ETS1-6(MA). Document and present solutions that include specifications, performance results, successes and remaining issues, and limitations.

 

One-page notes/posters

Idea: Students show what they learn by creating a large, colorful single page poster with graphics and text. Why? One-pagers are visually attractive; help students organize their thoughts; give students an opportunity to show originality & creativity.

Materials: Large pieces of paper (art pads/newsprint pads.) e.g. 18”x12” or 18”x24”; colored pencils, markers, pastels, pens, etc.

Who this project typically appeals to: Students comfortable with art. They want to create their own unique layout and drawings from scratch. Challenges: Some students don’t feel comfortable with their artistic skills. These students will benefit from us providing templates to choose from.

This kind of project will be new to many students: we need to show them a few examples.

Rubrics/parameters (possible ideas)

English Language Arts/Literature

• Create a drawing or icon which represents the theme.

• Create a sketch (or decoupage a photo) showing the setting (location/time period.) Have a couple of sentences describing this.

• Include quotations

• Describe main characters; info about a character arc.

• Describe themes; questions that the author is asking us; responses.

• Write something that they personally connected with.

History/Social Studies

• Create a drawing or icon which represents the theme.

• Make connections between the text and current events

• Create a sketch (or decoupage a photo) showing the setting (location/time period.) Have a couple of sentences describing this.

• Include quotations from related primary sources.

• Examine several historical figures in this unit and their impact on history

• Write something that they personally connected with.

Science

• Create a drawing or icon which represents the main ideas

• If about the discovery of a law of physics or chemistry, create a sketch (or decoupage a photo) showing the setting (location/time period.) Have a couple of sentences describing this.

• Relevant equations

• Examples of how this scientific principle operates in the real world.

External resources

We Are Teachers – One-pager-examples ELA

cultofpedagogy.com – One pagers

Colonialsd.instructure – Sample instructions and rubric

Alvord Schools – Sample one pager instructions (PDF)

Learning Standards

Common Core ELA Science

CCSS.ELA-LITERACY.RST.9-10.2
Determine the central ideas or conclusions of a text; trace the text’s explanation or depiction of a complex process, phenomenon, or concept; provide an accurate summary of the text.

CCSS.ELA-LITERACY.RST.9-10.7
Translate quantitative or technical information expressed in words in a text into visual form (e.g., a table or chart) and translate information expressed visually or mathematically (e.g., in an equation) into words.

NGSS Science and Engineering Practices

O​​btaining, Evaluating, and Communicating Information

Communicate scientific and technical information (e.g., about the process of development and the design and performance of a proposed process or system) in multiple formats (including oral, graphical, textual and mathematical).

NGSS Evidence Statements – Observable features of the student performance by the end of the course: Students use at least two different formats (including oral, graphical, textual and mathematical) to communicate scientific and technical information, including fully describing the structure, properties, and design of the chosen material(s). Students cite the origin of the information as appropriate.

Essential Knowledge and Skills Statements (ESS)

National Association of State Directors of Career and Technical Education Consortium (NASDCTEc) 2008

Communications: Use oral and written communication skills in creating, expressing and
interpreting information and ideas including technical terminology and information.

 

High effectiveness of covid-19 vaccines, breakthrough cases and the base rate fallacy

How effective are the mRNA covid-19 vaccines? Don’t some vaccinated people nonetheless get covid-19? Doesn’t that mean that vaccines don’t work?

Not at all. This is a logical error known as the base rate fallacy.  What is the base rate fallacy?

Consider a soldier going out into battle against an army armed with bows & arrows. Doctors and experts say, “Protect yourself as best you can! Wear a suit of armor!”

This soldier went to the battlefield. Later he returns, complaining about pain in his shoulder. Here he is:

Should we conclude that a suit of armor is useless? If we look at this one person, alone, without comparing him to anyone else, it might seem that way.

But that’s illogical: there is no way to tell the effectiveness of wearing armor versus not-wearing armor by looking only at the people wearing armor.

We need to compare the rate of wounds from people in armor to the rate of wounds from people refusing to wear armor. When we do so we come to a very different conclusion:

Wow, it now is clear that when we take all the data into account, wearing armor makes one far safer.

Let’s see how this helps us understand the effectiveness of vaccines, and what it really means about breakthrough cases.

Tom Buytaert writes

The more people in society are vaccinated, the more of the deaths will be among vaccinated people. Imagine a scenario where 95% is vaccinated, with a vaccine that is 90% effective, in a target group where IFR is 10% (80+).

In reality, as we now know, covid-19 vaccines are a lot more effective than 80%. So the infographic below even understates the advantage of being vaccinated!

In that scenario the total number of deaths among vaccinated people will be 2x higher, but their individual chance is 10x lower than that of people who are unvaccinated.

So that might sound like the vaccines are not working?

Well, that the total number is higher among the vaccinated is thus normal – it is a result of the fact that there are simply more vaccinated people around.

Similarly, if there are more red cars driving around on the roads, more red cars will crash. That doesn’t mean that the color red makes driving less safe.

You can see the actual (individual) protection provided by the vaccine on the right side, which shows the odds of dying* for vaccinated and non-vaccinated groups.

* For this fictional scenario of only 90% protection. In reality protection is a lot higher.

The vaccines do not offer 100% protection against heavy illness or death (although it is very close) .

So sometimes a (small!) part of the vaccinated people will still end up in hospital. It’s much less likely than if you are not vaccinated, but sometimes still possible.

In my infographic you see two views of the same situation: absolute numbers and odds.

left box:
– 10 unvaccinated, of which 1 died
– 190 vaccinated, of which 2 died

right box:
– 1 out of 100 vaccinated people died
– 10 out of 100 unvaccinated people died

The left box corresponds to “the numbers” that you will see in the news and on dashboards published by CDC, Worldometer, RIVM,…

But the right box is the one that counts. That one indicates that the vaccines do make a big difference.

So if you might hear about vaccinated people still ending up in hospital, keep this in mind. This is an example of the ‘Base Rate Fallacy’:

If someone is throwing percentages at you, a good reflex is to ask yourself: “exactly WHAT is this a percentage of?”

Or you could draw an example: “If I have 100 people in this group and 100 in the other, what happens to those percentages then?”

This infographic clearly shows us what group we should be comparing with what other group.

Related articles

“Israel, 50% of infected are vaccinated, and base rate bias”

Katelyn Jetelina writes

The statistic that’s concerning most (and that’s in the news) is a detail the Director General of the Health Ministry of Israel (Professor Chevy Levy) said during a radio interview. When asked how many of the new COVID19 cases had been vaccinated, Levy said that, “we are looking at a rate of 40 to 50%”. This must mean the Delta variant is escaping our vaccines, right? When I started digging into the numbers, though, this might not be as alarming as it seems.

This is likely an example of base rate bias in epidemiology (it’s called base rate fallacy in other fields). Professor Levy said that “half of infected people were vaccinated”. This language is important because it’s very different than “half of vaccinated people were infected”. And this misunderstanding happens all. the. time.

read more here Covid, breakthrough infections data – Your Local Epidemiologist

Another way of showing the logical errors in the base rate fallacy:

Marc Rumilly created this graphic

To be clear, “The numbers in this image were made just to make the phenomenon very obvious and clear/simple to see (I should have made the fine print at the bottom bigger, haha). But I also did a version with real data from Israel, with the data source cited:”

__________

Kristen Panthagani writes

People are looking at the percent of vaccinated hospitalizations and getting alarmed. But by itself, this number can’t tell you much about how the vaccines are working, as it’s highly dependent on the rate of vaccination in a community. Here’s some maths to show what I mean

Learning Standards

Common Core Math – Statistics & Probability

Making Inferences & Justifying Conclusions

CCSS.MATH.CONTENT.HSS.IC.A.1
Understand statistics as a process for making inferences about population parameters based on a random sample from that population.

CCSS.MATH.CONTENT.HSS.IC.B.3
Recognize the purposes of and differences among sample surveys, experiments, and observational studies; explain how randomization relates to each.

CCSS.MATH.CONTENT.HSS.IC.B.6
Evaluate reports based on data.

Mechanical equilibrium lab

This introduction comes from  Being Brunel: Notes From a Civil Engineer

What is mechanical equilibrium? Why do we study it?

This introduction comes from  Being Brunel: Notes From a Civil Engineer

If civil engineering was religion (and in a way it is; institutionalised by men in funny hats), the first commandment would be: “Thou shalt always have static equilibrium”

The principle is easy: the sum of all the actions acting on a structure should come to zero….

The logic goes as such:

  • Structures neither move, nor do they accelerate

  • Therefore the ‘velocity’ of the structure, and all of the components that make it, is always zero.

  • That means that the net force on the structure is zero (Newton’s first law)

  • All forces applied to a structure are due to accelerating masses (Newton’s second law)

  • At a global level these actions on the structure are resisted by the reactions of its supports (Newton’s third law)

______________

This is going to have to be true with anything we safely build, for instance:

In this lab we will see that the Σ F (the sum of all forces) equals 0.

Mechanical equilibrium lab

Equipment

Meter sticks, spring scales

table clamps, rod clamps, collar hooks, metal rods (crossbars)

string

More about this and related labs

Inertia and Mechanical Equilibrium labs

An elegant experiment in mechanical equilibrium, J N Boyd and P N Raychowdhury, Physics Education, Volume 20, Number 5, 1985

Walking the plank lab

Concept Development Practice Page Static Equilibrium

Equilibrium and Statics, The Physics Classroom

 

Physics curriculum resources

Physics curriculum resources – Please note that the topics here are NOT presented in the order that you should teach them. Every teacher does that differently.

The major units are alphabetical (Circular motion, electromagnetism, fluids, forces, etc.)

Within each of these units we find various topics. Choose the ones you want and use them in the order that best meets your needs. Do not feel like you need to cover every topic within one school year. None of us has the time to do all of that.

Biology Weekly Guide 2021-22

How to take notes (various methods, journaling, etc.)

Week 1 – Back-to-school activities and events.

First day of class never should focus on “syllabus, standards, policies, etc.”

21st Century Problems – students work in small groups

Classroom behavior expectations

Especially in the first week, don’t “tell” students note-taking expectations. Instead model note taking & journaling.

Note taking and note journaling

Discussion: What is Biology? In what ways does this topic overlap Chemistry, Ecology, and other sciences?

School, homework, grading policies.

__________________________

Week 2- What is life made of?

Discuss note taking expectations

phenomena

Elements Infographic What’s It All Made Of Earth Humans, and Universe image 2

What are elements, in general?

Elements manipulatives and cards, “Building the periodic table” handout

How atoms make up molecules, organelles, cells, and tissues

Tissues of the human body

__________________________

Week 3 –What is life made of?

phenomena – You Are What You Eat!

You Are What You Eat classic PSA (1983)Time for Timer classic public service announcements

You Are What You Eat video

Elements necessary for life – Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, Sulfur, and trace elements

“Molecular model lab: lesson plan

Claims Evidence Reasoning (CER) assignment

__________________________

Week 4 – Major building blocks of life

phenomena – tbd

Synthesizing organic molecules

2D and 3D shapes of molecules

PhET Molecule shapes

Major families: Carbohydrate, Lipids (“fats”), Protein, Nucleic Acids – their role in living things.

Labs: Build monomers of each; then connect monomers to make polymers. Monomers may be made of colored construction paper cutouts; Legos; or other linkable manipulatives.

__________________________

Week – genetics

phenomena – tbd

Gregor Mendel and origin of genetics

Human phenotypes that show Mendelian inheritance

For the simplest of traits

Punnett Squares. How likely is it that a trait will be inherited?

Punnet squares Monohybrid, Dihybrid, and Trihybrid Crosses

Build large colorful posters to hang on the walls

__________________________

Week – Genetics

For more complex traits

Punnet squares Monohybrid, Dihybrid, and Trihybrid Crosses

What exactly ARE the things inside cells that are being passed down?

What is genetic material?

What are chromosomes?

Typical number of chromosomes in cells, haploid/diploid

__________________________

Week  making sex cells and their connection to DNA

Meiosis: How do women make eggs? How do men make sperm?

DNA bases, nucleotides, and how they wind into a helix.

Analogies: DNA is like an alphabet, a word, a sentence or a book.

Lab: Create genes and do meiosis with hands-on Lego manipulatives

__________________________

Week DNA

DNA replication

Students model DNA replication with manipulatives

DNA transcription (make mRNA copy of the DNA)

Students model this with manipulatives

DNA translation and the genetic code: mRNA into protein

Students model this with manipulatives

__________________________

Week – More on genetic

More videos and apps on DNA translation and the genetic code: mRNA into protein

Teaching protein translation with manipulatives: Hands on!

Mutations (errors)

Students model mutations with manipulatives

__________________________

Week – Genetic engineering and genetic diseases

It is not always so simple! Non-mendelian inheritance.

Genetic engineering

Genetic diseases

Claims Evidence Reasoning (CER) assignment

__________________________

Week – How do we build and repair tissue?

phenomena

Babies starts off with small hands, arms, etc. How do they to full size?

We might injure ourselves – how do we heal cuts?

How do we heal broken bones?

The cell cycle (M, G1, S, and G2 phases)

How a scab forms

How torn muscles or tendons repair themselves

How we build new bones: Remodeling Osteoclasts and Osteoblasts

__________________________

Week – Body systems

Circulatory, Heart

Lungs

How do oxygen and CO2 molecules diffuse through small blood vessels? In the lungs, and in the rest of the body

(a) short videos, Socratic discussion, animations; (b) students create a posterboard subway-style map (markers, pencil, or website/app)

__________________________

Week – components of blood

Digestive system

Excretory system

(a) short videos, Socratic discussion, animations; (b) students create a posterboard subway-style map (markers, pencil, or website/app)

__________________________

Week – Sending and receiving signals

The brain and CNS

myths about the CNS

nerves, nervous system

__________________________

Week Homeostasis

What are hormones

endocrine system

Homeostasis and feedback

__________________________

Week a

How are cells powered

cellular respiration

photosynthesis

__________________________

Week – Diversity of life on Earth – week 1

Animal kingdom

Plant kingdom

__________________________

Week – Diversity of life on Earth – week 2

Fungi kingdom

Bacteria Kingdom

Archaea kingdom

Protista – a super group of several different kingdoms

Viruses

__________________________

Week – tbs

populations, communities, ecosystems, biomes.

Biomes

Population interactions and diversity – Limit factors and ecological niches

Claims Evidence Reasoning (CER) assignment

__________________________

Week a

Population limits and species interactions

Claims Evidence Reasoning (CER) assignment

__________________________

Week tbd

Symbiosis: (A) Autotrophs and Heterotrophs, (B) mutualism, commensalism, parasitism

(a) short videos, Socratic discussion, animations; (b) students create a posterboard subway-style map (markers, pencil, or website/app)

__________________________

Week – Ecological succession

Succession CK-12

Henry Chandler Cowles, one of the founders of the field

Primary and secondary succession

Claims Evidence Reasoning (CER) assignment

__________________________

Week tbd

Matter cycles: Carbon, Nitrogen, Phosphorus, Water, Hydrogen

__________________________

Week Evolution by natural selection

Charles Darwin’s Voyage of Discovery

Darwin’s finches

Fossils: Evidence of evolution over time

__________________________

Week Evolution

Convergent evolution – analogous features

Homologous structures – organisms inherited the same basic design from a common ancestor.

Turning sequences of fossils into stories

__________________________

Week tbd

Natural selection

Artificial selection

__________________________

Week – Creating cladograms (family trees of life)

clades & phylogenies

clades rotate = equivalent phylogenies

__________________________

Week tbd

evolution of Dinosaurs

evolution of whales

Evolution of humans

__________________________

Week – Global warming

Global warming and greenhouse gases

The Ozone layer and CFCs

Global warming has not stopped

Global warming Industry knew of climate change

Yes, the climate has always changed. But this shows why that’s no comfort: XKCD infographic

What is a chemical?

What is a chemical?

Many people think that a chemical is a man-made (artificial) molecule.

Others say that some chemicals are man-made, while others are natural, but they often don’t have specific definitions.

On top of that, many people feel that “chemicals are bad for you.”

The confusion likely exists because – as surprising as it sounds – until recently there never has been an exact definition of the word.

We can’t do anything in science, or communicate anything that we have learned, without specific and exact definitions. So in science we do have specific definitions for atoms, elements, compounds and molecules.

But although the word “chemical” is widely used, until recently no attempt was made to precisely define it.  What we can do is look at scientific papers and see how the word has been used:

A chemical is any substance consisting of matter.

This includes any liquid, solid, or gas.

A chemical is any pure substance (an element) or any mixture (a solution, compound, or gas).

They can either occur naturally or can be created artificially.

What Is Not a Chemical?

If anything made of matter is made up of chemicals, which means that only phenomena that aren’t made of matter are not chemicals: Energy is not a chemical. Light, heat, and sound are not chemicals—nor are thoughts, dreams, gravity, or magnetism.

What Is a Chemical and What Isn’t a Chemical? By Anne Marie Helmenstine, ThoughtCo, 12/7/2019

Surprising, eh? You’re made of chemicals! All trees, plants, and grass are made of chemicals. The Earth, moon, asteroids, and everything we can touch is made of chemicals. A single atom of gold, a sodium ion dissolved in our blood, a molecule of Vitamin C, are all chemicals.

At this point please see Every food we eat is made of nothing but chemicals!

 

 

All foods are made of nothing but chemicals

Background knowledge: What is a chemical?

Would you like chemicals added to your food? What you like chemicals in your food?

Think carefully before answering. This isn’t supposed to be a trick question.

But because of a common misunderstanding, it feels like one, right?

Look at these. Imagine you grow these foods yourself, organically, on a small scale farm. You don’t add anything. Just seeds, sunshine, soil, and water.

Many people think that these foods would then be “chemical free.” But they’d be incorrect – in fact, all of these foods are literally nothing but chemicals!

Or consider running your own farm. You don’t add “chemicals.” You raise your cattle free range, in the old fashioned way.

Cattle farming, Wikipedia

The meat from your cattle is all natural, organic. Many people might think that these meats are “chemical free.” But they’d be incorrect – in fact, all of these cuts of beef are literally nothing but chemicals!

image – Lisovskaya Natalia / Shutterstock.com

All foods are made of nothing chemicals

Our food would not be safer if it was free from chemicals – our food would just be non-existent.

It is meaningless to ask “is a chemical safe or dangerous”?  Safety depends only on the amount of a chemical.

Consider all of these chemicals in our food:

* Dihydrogen monoxide (H2O, water)

* Sodium chloride (NaCl)

* Magnesium chloride (MgCl2) – common salts.

* Iron (a metal, group 8 on the periodic table)

* Selenium (a metalloid, group 16 on the periodic table)

Yes – even metals are part of our food. Selenium, for example, is used in some amino acids – that’s what protein is made of.

* dimethyl-trimethylcyclohex-enyl)nona-tetraen-ol aka Vitamin A, aka retinol.

For every one of these chemicals, if we have too little we will die.

Or if we have too much then we’d also die.

Proper health depends on the dose.

It turns out that literally thousands of chemicals are absolutely necessary for us to stay alive.

But wait, that’s a complex chemical with a big name?! Jane and Moonflower explain why the names don’t matter.

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Our friend Morpheus explains it quite succinctly

ability to pronounce a chemical ingrdient is not an argument

Consider a banana. Would you eat one if you knew what it was made of?

This image is from James Kennedy, Chemistry teacher

all-natural-banana chemical ingredients

These chemicals are all safe and healthy – in the quantities that they exist in this food.

Ethyl butyrate creates part of the smell and taste of banana, pineapple, and strawberry.

b2 b1

Consider Isoamyl acetate (aka isopentyl acetate), also from banana.
b4 b3

(These images Wikipedia)

These are chemicals, yet are entirely safe.

Now what if you took one of these chemicals but consumed 1000 times the normal amount?

Then that chemical could be toxic (poisonous) or carcinogenic (cancer-causing.)

Does this “prove” that this chemical is really dangerous?

Not at all – because most chemicals have no danger below a certain dose.

When you hear someone say that a chemical “causes cancer” – know that most chemicals in natural foods could do the same thing, if given in massive over-doses.

“Obviously” deadly chemicals

Arsenic, cadmium and lead are heavy metals, normally considered poisons. We never add them on purpose to food. We monitor foods to make sure that they’re below a certain level.

But should we demand that our foods have zero amounts of these metals? No way.

Those metals exist naturally, in small amounts in Earth’s crust and soil. So they’re taken up in small amounts in most of our foods.

There is no such thing as food without tiny amounts of these metals. If you tried to totally avoid them, then you’d starve to death.

The chemical isn’t the problem – it’s the amount that matters.

10926429_840093996060611_3783692163074088285_n

Obviously, there are some chemicals we should try to stay away from:

Digoxin (purified extract of the foxglove plant)

Nicotine – contact with pure liquid nicotine causes death within hours

Sodium cyanide

Batrachotoxin (toad skin poison)

CO (Carbon monoxide) – in normal atmospheric amounts – is harmless.  But in larger amounts produced by a malfunctioning home heating system, or a car in a garage, CO is deadly.

Sodium fluoroacetate – This occurs naturally in dozens of plants in Australia, Brazil, and Africa. This plant is extremely toxic to any animal that eats it. When concentrated in pure form, it is sold as a pesticide called “1080.”  Nasty stuff.

Mailard reaction

During cooking, countless organic chemicals are produced.

This is true even using organic foods and old-fashioned cooking methods.

You can read about this at the Maillard Reaction: from Compound Interest

If these chemicals were isolated and eaten in overdoses they would cause cell damage or cancer. Does that mean that all cooked food is deadly? Obviously not. So what is the logic failure here? It’s not the molecule – it’s the amount.

Compound Interest: The Maillard reaction

_______________________________________________________________________

Are “carcinogenic” chemicals produced when foods are cooked a cause for concern?

excerpted from an article by Takayuki Shibamoto | July 16, 2012

Cooking food is the major process adopted to produce flavor chemicals, which give foods a characteristic desirable roasted or toasted flavor. More than 1,000 low molecular weight compounds are known to be produced once a food is heated, and the number of known compounds is increasing steadily.

The amounts of these chemicals formed are generally in very trace levels (around the level of µg/kg of food or parts per billion, ppb), but for most of these compounds, detailed information about possible toxicity at this level is not yet established.

One of these compounds is 4-Methylimidazole (4-MEI), which forms from a reaction between amino acids or proteins and sugars, carbohydrates, or lipids when exposed to heat.

4-Methylimidazole.svg

{ Naturally produced in roasted foods, grilled meats, coffee and some fermentation – Wikipedia }

This past March, an independent study commissioned by the consumer interest group Center for Science in the Public Interest (CSPI) found that four of the best-selling sodas (Coca-Cola, Diet Coke, Pepsi and Diet Pepsi), which use caramel color produced by heating sugar and ammonia, contain potentially unsafe levels of 4-MEI, which according to the report had recently been linked to cancer.

“The average amount (138 µg) of [4-MEI] that our tests found in a 12-ounce can of [cola] is 4.8 times greater than California’s 29 µg-per-day limit, indicating a lifetime risk of cancer of 5 out of 100,000 people,” CSPI Executive Director Michael Jacobson wrote in a letter to the US Food and Drug Administration that described the results of the study.

This has caused a stir in the consumer research community, with many advocating for the reduction or elimination of 4-MEI from marketed food and drinks.

But I do not believe 4-MEI is harmful at the levels found in these products. Stating that these sodas contain potentially unsafe levels of the chemical is misleading—it is present only trace levels. Furthermore, the supposed cancer link stems solely from a handful of animal experiments; there is currently no evidence of a link between 4-MEI and disease in humans.

….this concern over the presence of 4-MEI in popular soda brands is just the latest in the periodic excitement that is stirred up over chemicals that are formed in foods when they undergo processing and cooking. Other potentially carcinogenic chemicals that have raised concerns in the past include polycyclic aromatic hydrocarbons, N-nitrosamines, aromatic amines, and acrylamide.

Whenever one of these carcinogens is reported in cooked food, many people from various specialties, including food sciences, regulatory agencies, and medicine, not to mention consumers, react by giving the new chemical concentrated attention and intense discussions about how to reduce it. However, in each case, after some time has passed, attention fades away, in part because there is no practical way to remove these chemicals from cooked or processed foods and also because there is no evidence that the trace levels consumed present any health risk to humans.

All substances are poisons; only the dose differentiates the poison from a remedy. This concept was developed by Paracelsus, a medical doctor in Europe in the 16th century, and it is useful in evaluating risk in our daily lives by considering examples of well-known substances with low and high toxicity consumed today.

For example, water might be considered one of the least toxic substances that we commonly encounter. However, there are many reports of water toxicity in the scientific literature. Too much water can, indeed, be fatal. For example, in 2002 a student was undergoing a fraternity initiation ordeal, in which he was required to drink up to 5 gallons in a short period of time. Consumption of this amount of water resulted in the dilution of the electrolytes in his blood to the point that normal neurological function was lost, and the young man sadly died.

….In the case of 4-MEI, the amount present in foods is extremely low and it is hard to predict any kind of adverse health effect at these levels. People have been consuming numerous heat-induced chemicals, including 4-MEI, since the discovery of fire some half a million years ago, and there has been no clear evidence of any specific health problems to date.

Thus, while it is extremely important to continue ongoing research to determine the toxic level of 4-MEI, I personally choose to enjoy flavorful, cooked foods, without fear for my health.

Takayuki Shibamoto is a distinguished professor in the Department of Environmental Toxicology at the University of California, Davis, and an associate editor of Journal of Agricultural and Food Chemistry.

______________________________

Does this mean that everything is safe? Not at all.

This is just to show you that chemicals, in general, are nothing to be afraid of – and in fact, they are what you are made of.

What kinds of foods do cause cancer?It depends on the specifics: what type of meat & how was it raised; what type of plant and how was it farmed; how much was consumed, and how often.

There is a growing body of evidence that eating meat in large quantities is a health risk.

Eating only small amounts of meat, in contrast, does not appear to be risky. also, free-range naturally fed cattle appear to have a different profile of fatty acids, and they possibly may be better for you.

The World Health Organization has determined that dietary factors account for at least 30 percent of all cancers in Western countries and up to 20 percent in developing countries. When cancer researchers started to search for links between diet and cancer, one of the most noticeable findings was that people who avoided meat were much less likely to develop the disease. Large studies in England and Germany showed that vegetarians were about 40 percent less likely to develop cancer compared to meat eaters.1-3

In the United States, researchers studied Seventh-day Adventists, a religious group that is remarkable because, although nearly all members avoid tobacco and alcohol and follow generally healthful lifestyles, about half of the Adventist population is vegetarian, while the other half consumes modest amounts of meat. This fact allowed scientists to separate the effects of eating meat from other factors.

Overall, these studies showed significant reductions in cancer risk among those who avoided meat.4 In contrast, Harvard studies showed that daily meat eaters have approximately three times the colon cancer risk, compared to those who rarely eat meat.

A number of hypotheses have been advanced to explain the connection between meat consumption and cancer risk. First, meat is devoid of fiber and other nutrients that have a protective effect. Meat also contains animal protein, saturated fat, and, in some cases, carcinogenic compounds such as heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH) formed during the processing or cooking of meat. HCAs, formed as meat is cooked at high temperatures, and PAHs, formed during the burning of organic substances, are believed to increase cancer risk.

In addition, the high fat content of meat and other animal products increases hormone production, thus increasing the risk of hormone-related cancers such as breast and prostate cancer.

http://www.pcrm.org/health/cancer-resources/diet-cancer/facts/meat-consumption-and-cancer-risk

Related articles

Is The Food Babe A Fearmonger? Scientists Are Speaking Out, NPR

Vani Hari, a.k.a. “The Food Babe,” finally responds to critics. By David Gorski

Microwaves and nutrition by Steven Novella

Glyphosate Vs. Caffeine: Acute and Chronic Toxicity Assessments Explained, Alison Bernstein, Food and Farm Discussion Lab

Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

6.MS-LS1-3. Construct an argument supported by evidence that the body systems interact to carry out essential functions of life… Essential functions of life include obtaining food and other nutrients (water, oxygen, minerals),

8.MS-LS1-7. Use informational text to describe that food molecules, including carbohydrates, proteins, and fats, are broken down and rearranged through chemical reactions forming new molecules that support cell growth and/or release of energy*

Massachusetts Comprehensive Health Curriculum Framework

Nutrition Students will gain the knowledge and skills to select a diet that supports health and reduces the risk of illness and future chronic diseases.

Ore genesis (how ore deposits are created)

Main idea:

In previous units we have learned about metals and gems.

We further learned about ores (rock that contains valuable minerals that can be mined and sold at a profit.)

In this unit we learn several ways that ore deposits were created in the first place.

These processes are called ore genesis. (Not to be confused with the similar-sounding, but completely different, orogenesis.)

Pre-loading vocabulary

deposit (verb) – to put something down (e.g. money in a bank, or particles in a riverbed)

deposition (noun) – the process of silt and sediment building up in an area.

Here we see a GIF of particles moving through water, and eventually being deposited on the sea floor (deposition.)

Over long periods of time, this deposited material can be chemically cemented together into sedimentary rock. This is term sedimentation.

sedimentation (verb) – the process of particles settling or being deposited.

sedimentary rock (noun) – rock formed from fragments of other rocks or the remains of plants or animals.

element (noun) – Elements are pure substance made from a single type of atom. For all practical purposes, an element is something that cannot be broken down into anything simpler. Examples: Oxygen, Carbon, Hydrogen, Gold, Iron, etc.

Microbial Genomics and the Periodic Table, Lawrence P. Wackett, Anthony G. Dodge and Lynda B. M. Ellis

hydrothermal vent (noun) – An opening on the seafloor that emits hot, mineral-rich solutions.

GIF from gfycat.com

mid-ocean ridge (noun) – underwater mountain range.

National Oceanic and Atmospheric Administration (NOAA), ETOPO1 Global Relief Model,
http://www.virginiaplaces.org/geology/rocksdui4.html

ore (noun) – deposit in the Earth of minerals containing valuable metal.

ore body (noun) – a well-defined mass of ore-bearing rock

from Applied Geochemistry
Advances in Mineral Exploration Techniques, Macheyeki et al.

subduct (verb) – When one tectonic plate hits another, and one of the plates is forced below the other. The subducted plate is the one going deeper into the mantle.

subduction zone (noun) – An area where one tectonic plate slides under another.

Deep versus surface processes

Sometimes we classify ore producing processes as either

supergene – those that occur near the surface.

hypogene – those that occur deep under the Earth’s surface.

Ways that ore deposits form

A National Geographic infographic describes three ways that ore deposits form:

(1) Ore deposits created underwater, within sedimentary rock like shale.

The rock/shale forms from nearby volcanic arc, settles on seafloor in layers. This sediment is rich in minerals that contain lead, silver, zinc.

As layer after layer of sediment build sup, the pressure on lower layers increases. The temp increases. The lower layers then begin to melt.

When sea water seeps in through cracks in the crust, the rocks expel these metals, which form ore bodies. Usually occurs within subduction zones.

(2) Subduction zone ore deposits.

Tectonic plates contain large quantities of water. As a tectonic plate is subducted into the mantle it heats up and releases this water. The resulting fluid travels up to the rocks above the subduction zone.

Combined with significant heat, this fluid-filled environment can create the right conditions for ore deposits to form. Includes Gold and copper.

(3) Hydrothermal vent ore deposits.

Deep sea hydrothermal vents line mid-ocean ridges. These vents spew incredibly hot water, which contains dissolved metals like copper, lead, zinc, and iron.

When this super heated liquid hits cold ocean water, the metals become solid and settle onto the ocean floor. Over time they build up on the seafloor near these vents, creating ore bodies than can be minded.

Looking on a global view, where do these processes occur?

f

See Compare and Contrast: Ore Deposition Infographic

Ores from hot water

This text is from the American Museum of Natural History

‘”Driven by heat from bodies of molten rock in the crust, hot water circulates through cracks, dissolving minerals in the rocks through which it passes. As the water moves into cooler rocks, the dissolved minerals precipitate and accumulate in fractures and cavities. Many metallic ore deposits, such as those represented in the samples shown here, form in this way.”

How weathering can produce ore deposits

Here are two examples of how weathering creates ores from Earth Science (Tarbuck, Lutgens, Tasa)  This process is called secondary enrichment.

(A) Chemical weathering coupled with downward-percolating water removes undesired materials from decomposing rock.

This leaves the desired elements enriched in the upper zones of the soil.

(B) The second way is basically the reverse of the first. Desirable elements that are found in low concentrations near the surface are removed and carried to lower zones, where they are redeposited and become more concentrated.

Learning Standards

MS-ESS3-1. Construct a scientific explanation based on evidence for how the uneven distributions of Earth’s mineral, energy, and groundwater resources are the result of past and current geoscience processes.

[Clarification Statement: Emphasis is on how these resources are limited and typically non-renewable, and how their distributions are significantly changing as a result of removal by humans. Examples of uneven distributions of resources as a result of past processes include but are not limited to petroleum (locations of the burial of organic marine sediments and subsequent geologic traps), metal ores (locations of past volcanic and hydrothermal activity associated with subduction zones), and soil (locations of active weathering and/or deposition of rock).]

Disciplinary Core Ideas – ESS3.A: Natural Resources

Humans depend on Earth’s land, ocean, atmosphere, and biosphere for many different resources. Minerals, fresh water, and biosphere resources are limited, and many are not renewable or replaceable over human lifetimes. These resources are distributed unevenly around the planet as a result of past geologic processes.

Crosscutting Concepts – Influence of Science, Engineering, and Technology on Society and the Natural World

All human activity draws on natural resources and has both short and long-term consequences, positive as well as negative, for the health of people and the natural environment.

HS-ESS3-2. Evaluate competing design solutions for developing, managing, and utilizing energy and mineral resources based on cost-benefit ratios.

[Clarification Statement: Emphasis is on the conservation, recycling, and reuse of resources (such as minerals and metals) where possible, and on minimizing impacts where it is not. Examples include developing best practices for agricultural soil use, mining (for coal, tar sands, and oil shales), and pumping (for petroleum and natural gas). Science knowledge indicates what can happen in natural systems—not what should happen.]

4-ESS3-1. Obtain and combine information to describe that energy and fuels are derived from natural resources and their uses affect the environment.

HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems

[Clarification Statement: Examples of environmental effects could include loss of habitat due to dams, loss of habitat due to surface mining, and air pollution from burning of fossil fuels.]

Pacing guide for year long Physics course

A pacing guide helps us decide what we’re going to cover over the course of a year. I especially find it helpful to set one up as a week-by-week plan.

Pacing guides are important structures to help us stay on track throughout the year; this is important for several reasons. In some school districts your students may need to pass a state exam in physics such as the MTEL or Regents. Some students want the opportunity to go onto AP Physics, or to major in a STEM subject in college. They are best served with a rich curriculum covering many important areas.

Yet a pacing guide is not scripture. The needs of students will vary from district to district, from year to year. Sometimes you have exceptionally well-prepared students who already know some of the material covered below. Other years you may have a class that wasn’t as well prepared in their middle school years; they find even the basic concepts very challenging.

A pacing guide is made for us teachers and our students. It shows we are doing in class each week; it can be as detailed as showing what we are doing each day. The guide is about ideas and content, not about administration.

Pacing guides tell us – what ideas are we covering today/ What phenomenon will we investigate? What labs or manipulatives will we use? What videos, GIFs, or infographics will we use? What equations will we introduce? Basically – you as the teacher decide – “What do I need to know, to walk into that classroom feeling fully prepared?”

Lesson plans tell us: what the “do now” is; what the skills and vocabulary goals are; what pedagogical methods the teacher will be using; what learning standards the lesson addresses. They are often designed in great detail; they vary significantly from district to district. In private conversations most teachers have told me that they don’t find school-demanded lesson plans to be very useful. Teachers might spend an hour a day or more on these; and then, over the course of our careers, they need to be totally rewritten in new formats when new trends develop.

Sometime later this month I will be placing a useful and detailed pacing guide for sale on Teachers Pay Teachers. Stay tuned.

– Robert Kaiser