Difference between revisions of "External Knowledge Training"
From eagle-rock.org
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* Gamma rays are penetrating, not ionizing colliding particles. They pass through things. They knock off electrons and are very energetic. | * Gamma rays are penetrating, not ionizing colliding particles. They pass through things. They knock off electrons and are very energetic. | ||
* X rays are the same as gamma rays but more energetic. X-ray photos create shadows.<br clear="all" /> | * X rays are the same as gamma rays but more energetic. X-ray photos create shadows.<br clear="all" /> | ||
+ | === 9 Nuclear reactors, uranium, chain reactions === | ||
+ | {{#ev:youtube|W1LkRO2fiVs|200|right| }} | ||
+ | This lecture is about: | ||
− | + | * How to get useful energy from radioactive elements. | |
+ | * Chain reactions and nuclear fission. | ||
+ | * U235 is more radioactive than U238, but there's much less of U235 on earth (U = uranium). | ||
+ | * Enrichment of uranium is removing what you don't want, for example by using centrifuges. | ||
+ | * Depleted uranium. | ||
+ | * Natural and oldest man-made nuclear reactors. | ||
+ | * The nature of chain reactions. | ||
[[Category:Divine School]] | [[Category:Divine School]] | ||
[[Category:Science]] | [[Category:Science]] |
Revision as of 21:20, 20 September 2012
- Most of the content of this page was first published on the FB page with the same name.
- This page is moderated by John Eagles.
Physics - Introductory Berkeley course
- All notes by John Eagles
1 Introduction
Today i started watching this introductory course in physics. It's a UC Berkeley course given by Richard Muller. He explains physics without using many equations. In this particular lecture he comments quite a bit on 9/11 related physics and dwells on terrorist shoe bombs. He advises the government in such matters, so his views seem a bit politically colored. But he really knows how to present laws of physics in a very understandable and close-to-life manner. I've learned quite some new things from watching this lecture.
2 Solar technology, coal reserves
Summary of topics lectured about:
- Calories of food
- Peripheral vision of the eyes detect especially motion
- Solar technology
- Tilt of the earth & the seasons
- Global warming in relation to the forming of clouds. When the climate heats up, more clouds may form and may counter the greenhouse effect.
- Canada is 2nd in the world after Saudi Arabia for its oil reserves, but Canada has it stored in oil sand and it's more expensive
- Natural gas & shale gas in comparison to oil
- Coal reserves: The USA has most reserves, then comes Russia and then China, Australia and India. These reserves are big in terms of energy compared to the world's oil reserves.
- Coal and methane can turned into gasoline, but it's still risky in case the oil prices are lowered.
- In politics, there's conflict between the issues of global warming and energy security.
- Coal is the cheapest form of energy.
- IPCC errors
- Sequestering CO2 and making clean use of coal
- CCS = Carbon Capture & Storage
3 Temperature scales
Topics in this video:
- Size of atoms
- Density of atoms
- What makes atoms move, what gives them the kinetic energy?
- Temperature = how much energy do things have
- Thermometers
- Scales of Celcius, Fahrenheit
- Liquid nitrogen experiments
- There are ca 1000 x more molecules in a fluid than in a gas of the same substance per volume
- Temperature of absolute zero on the Kelvin scale means there is no energy
- In the Kelvin scale the amount of energy is proportional to the temperature
- A fire extinguisher has liquid CO2
- Your subjective temperature measurement
- Hot air rises because it's less dense
- Conduction, convection, radiation
Lecturer is Bob Jacobsen
4 Thermodynamics intro
- The ideal gas law (relationship between volume & temperature)
- Movements of small and bigger molecules and atoms
- Energy efficiency of engines
- Refrigerators
- Air conditioners
- Entropy = a measure of disorder
5 Satellites, gravity
This lecture is about:
- Friction
- Movements of satellites
- Why frisbees and airplane wings lift
- Satellites move with 5 miles per second. They are falling but because the earth is curved, they fall with the earth curve
- Rockets escape velocity
- Gravity force between two people near to each other is ca mass of a mosquito
- What does it mean to be weightless
- How do spy satellites work. They have to be close to the ground. It takes them 1 1/2 hour to orbit the earth one time.
- Unmanned drones
- Weather and tv satellites orbit the equator at 22000 miles high and need 24 hours for one cycle: Geostationary satellites
- 24 GPS satellites go around in 12 hours.
6 Newton's laws, inertia, circular motion
Topics explained in this lecture, illustrated with several experiments:
- Newton's laws
- Inertia
- Circular motion
7 Radiation, radioactivity
- Ionizing radiation knocks electrons off atoms.
- We're exposed to some amount of ionizing radiation all the time.
- Tritium is used in some watches.
- Damaging of DNA is what causes cancer.
- Sieverts - Grays - rems.
- 2500 rems (25 Sieverts) on average causes 1 fatal cancer. It's a probability.
- Radiation illness - requires much less than a dose causing cancer.
- About percentages of increase of cancer because of radioactivity.
- Alpha rays don't penetrate deeply, are stopped by the skin.
- X-rays.
8 Global warming, radioactive rays, radiocarbon dating
- Categories of believers and non-believers in global warming.
- Errors in IPCC reports
- He quotes research stating that organic food is unhealthy?!?
- Chemotherapy & radiation therapy against cancer, how does it work?
- The energy release of exploding a nucleus is typically 1 million times more than energy released in chemical reactions.
- In the early universe almost all atoms probably were explosive or radioactive.
- Radiocarbon dating with C14, having a half-life time of 6,000 years. C14 is in the atmosphere because of cosmic radiation affecting C atoms. Living organisms take in a percentage of these C14 atoms. The amount of C14 in the atmosphere is constant.
- Potassium-Argon dating: A dating method using rocks.
- Beta rays are fast electrons.
- Alpha rays consist of small nuclei of 2 protons and 2 neutrons that form He atoms when the rays are stopped.
- Gamma rays are penetrating, not ionizing colliding particles. They pass through things. They knock off electrons and are very energetic.
- X rays are the same as gamma rays but more energetic. X-ray photos create shadows.
9 Nuclear reactors, uranium, chain reactions
This lecture is about:
- How to get useful energy from radioactive elements.
- Chain reactions and nuclear fission.
- U235 is more radioactive than U238, but there's much less of U235 on earth (U = uranium).
- Enrichment of uranium is removing what you don't want, for example by using centrifuges.
- Depleted uranium.
- Natural and oldest man-made nuclear reactors.
- The nature of chain reactions.