External Knowledge Training
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Physics - Introductory Berkeley course
- All notes by John Eagles
1
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
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
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
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.