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# Author Archives: New England Blogger

## Geodesy

### Geodesy combines applied mathematics and earth sciences to measure and represent the Earth (or any planet.)

NOAA National Geodetic Survey, from a PPT by Hawaii Geographic Information Coordinating Council

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from the  National Oceanic and Atmospheric Administration Ocean Service Education page on Geodesy:

### As positioning and navigation have become fundamental to the functions of society, geodesy has become increasingly important.

https://www.ngs.noaa.gov/INFO/WhatWeDo.shtml

https://oceanservice.noaa.gov/facts/geodesy.html

Precise Geodetic Infrastructure: National Requirements for a Shared Resource (2010) – Geodesy for the Benefit of Society

## Seismic waves

### P waves

Earth Science, Tarbuck & Lutgens, Chapter 8

### S waves

Earth Science, Tarbuck & Lutgens, Chapter 8

### Surface waves

Tarbuck & Lutgens

### Rayleigh surface waves

“The Rayleigh surface waves are the waves that cause the most damage during an earthquake. They travel with velocities slower than S waves, and arrive later, but with much greater amplitudes. These are also the waves that are most easily felt during an earthquake and involve both up-down and side-to-side motion.”

## How do we measure motions of the Earth?

### What is a seismograph?

Intro to be written

Earth Science, Tarbuck & Lutgens, Chapter 8

### This is a seismograph record.

Earth Science, Tarbuck & Lutgens, Chapter 8

## Mineral Identification

### All crystals are atoms in a three dimensional pattern. Here some examples.

Image from Molecular and Solid State Physics, http://lampx.tugraz.at

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## Cleavage

### Mica has 1d cleavage

Lumen Geology, Identify and classify common rock forming minerals.

## Fracture

### Chrysotile has splintery fracture.

Quartz has conchodial fracture

## Further examples

GG101 Lab Minerals

## Terminology

### Fibrous – Fracture surface shows fibres or splinters.

This section from

Geololgy, Rocks and Minerals, Univ. of Auckland

## What are laws of nature?

### This idea is held by some religious groups and some schools of philosophy. It isn’t necessarily related to religion; there are many non-religious people who believe in the necessary existence of natural law.

image from commons.wikimedia.org

## O’Neill cylinder

### Each could be 5 miles (8.0 km) in diameter and 20 miles (32 km) long, connected at each end by a rod via a bearing system. They would rotate so as to provide artificial gravity via centrifugal force on their inner surfaces.

(This section adapted from Wikipedia.)

A pair of O’Neill cylinders. NASA ID number AC75-1085

Rick Guidice, NASA Ames Research Center; color-corrector unknown

### Inhabitants on the inside of the outer edge experience 1 g. When at halfway between the axis and the outer edge they would experience only 0.5 g. At the axis itself they would experience 0 g.

Visions Of The High Frontier Space Colonies of 1970

## Rama

### In his 1973 science fiction novel Rendezvous with Rama, Arthur C. Clarke provides a vivid description of a rotating cylindrical spaceship, built by unknown minds for an unknown purpose.

http://www.nss.org/settlement/space/rama.htm

Rama video – artist’s homepage and resources

Ringworld video

## Learning Standards

SAT Subject Test in Physics
Circular motion, such as uniform circular motion and centripetal force

2016 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 Science and Technology/Engineering Curriculum Framework (2006)
1. Motion and Forces. Central Concept: Newton’s laws of motion and gravitation describe and predict the motion of most objects.
1.8 Describe conceptually the forces involved in circular motion.

## Great physics discussion questions!

Great physics discussion questions! These were written by Physicist Dr. Matt Caplan, who used to run the QuarksAndCoffee blog. That blog no longer exists, links to archived copies exist.

If everyone was Kung fu fighting, and their kicks really were fast as lightning, what would happen?

How many calories do superheroes burn using their powers?

What would happen if a 10 meter plasma sphere was transported from the Sun to Earth?

Dyson Sphere: Is there enough material in the solar system to build a shell to enclose the sun?

If it was cold enough for the atmosphere to condense, how deep would the ‘liquid air’ be?

Does my phone weigh more when the battery is charged?

How loud would a literal ‘shot heard round the world’ be?

Why are there seven colors in the rainbow?

Math

What are the odds of solving a Rubik’s cube by making random moves?

## Why are some moons spherical while others are shaped like potatoes?

### Why are some moons spherical while others are shaped like potatoes?

This blog post was written by Physicist Dr. Matt Caplan, who used to run the QuarksAndCoffee blog. That blog no longer exists, but I’m showing this archived copy of one of his posts for my students.

### This works out to about 240 km [1], right in the middle of the 200-300 km range of the more rigorous calculation!

(1) How High Can A Mountain Be? P. A. G. Scheuer, Journal of Astrophysics and Astronomy, vol. 2, June 1981, p. 165-169.

Web.archive.org copy
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## What factors control the height of a mountain?

### Don’t believe me? Even rock has a maximum amount of strength. Here is a GIF of what happens to solid rock when you put enough pressure on it! 🙂

Source: Unconfined compressive strength test of rock

Roy Blitz

## What else makes mountains rise or grow?

### This causes delamination to occur. Depending on the amount of material removed, the rate of new material added, and erosion, scenarios with net increases or decreases in elevation are possible after a delamination event. This sets another limit on how thick a crustal root can get (and thus how high a mountain range grow on the long term).

Source, Reddit comment

## Why are there some special spots on Earth where mountains can grow twice as high?

### So the Himalayas have double the thickness of the average continental plate, thus double the mountain height that would be considered “normal”.

George W Hatcher, Planetary Scientist, Aerospace Engineer

## References

How high can a mountain possibly get? Earth Science StackExchange

How High can a mountain get? 2 Earth Science Stack Exchange

How tall can a mountain become on Earth? Quora

What is the theoretical limit to how tall mountains can get on Earth? Reddit

Glacial Buzz Saw Hypothesis: New Scientist article

## Examples with math details

Why are some moons spherical while others are shaped like potatoes? Quarks & Coffee

How High Can Mountains Be? Talking Physics

How High Could A Mountain Be? Physics World hk-phy.org

How tall can I make a column of stone? Rhett Allain, Wired magazine columnist

### Related lab ideas

Play Doh Modeling Folds: Block Diagrams and Structure Contours

Play-Doh Modeling Folds: Block Diagrams and Structure Contours

Play Doh Introduction to Igneous Intrusions

Play Doh Unconformities

## Addressing the carbon monoxide claim

### Also, to be clear, single viral particles don’t make people sick. The disease is only spread if people inhale multiple exhalation water-virus droplets, each drop let being thousands of times larger than a viral particle, and each drop containing at least many hundreds of viral particles each. And these drops are what the masks are pretty good at filtering.

Image created by Fusion Animation.

## Addressing the low amount of oxygen claim

### The other claim is that these face masks “trap our breath” preventing us from getting oxygen, so that our O2 blood levels fall.  But see for yourself – they don’t do that!

Photo credit. Dr. Megan Hall

### Dr. Megan Hall writes:

Below is me in 4 scenarios. I wore each mask for 5 minutes and checked my oxygen saturation (shown as the percentage below) along with my heart rate (HR, in beats per minute) using noninvasive pulse oximetry. Keep in mind, immediately prior to this, I had been wearing the surgical mask for 5 hours.

Results:
No mask: 98%, HR 64
Surgical mask: 98%, HR 68
N95 mask: 99%, HR 69
N95 plus surgical mask (which is how most healthcare providers are wearing masks): 99%, HR 69.

## How well do masks work?

### Here is a video from Dr. Joe Hanson, from “It’s ok to be smart.” It is an awesome, slow-motion schlieren imaging experiment that demonstrates why masks work.

How Well Do Masks Work? (Schlieren Imaging In Slow Motion!)

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