Midterm review Flashcards
What is a fermi problem?
Fermi problems are “impossible” math problems where you use your intuition, logic, and order of magnitude estimates to come to a solution.
What is the key method while completing fermi problems?
Use powers of ten, or orders of magnitude in order to help you, and feel free to round.
What is the scientific theory?
A scientific theory is an explanatory and predictive idea that has been rigorously tested and shown to be verified in many experiments.
What is a consensus in science and why is it important?
A consensus is when the majority of scientists in a given field of study agree on the interpretation of experimental results and conclusions.
This is important because without scientists coming to a consensus, we wouldn’t be able to publish ideas and theories.
What is Falsification?
Falsification is the idea that you can prove a theory wrong.
What is pseudoscience?
If your explanation for a phenomenon is not falsifiable, then it is not scientific, but is instead pseudoscience.
What is Parallax?
Parallax - The phenomenon that the viewing angle to a faraway object changes as your baseline changes. The farther away the object, the smaller the angle change.
What is the equation for parallax?
d=1/θ
d=distance is parsecs
1 Au
θ = arcseconds
who was Eratosthenes?
Eratosthenes - was at one time the chief librarian of the library of Alexandria, and the first person to correctly measure the Earth’s circumference in the third century B.C.E., using shadows in Egypt.
Who was Hipparchus?
Hipparchus - built an observatory on the island of Rhodes in the second century B.C.E. He invented the magnitude system of brightness, and discovered the precession of the Earth, which moves like a top over the course of 26,000 years.
Who was ptolemy?
Ptolemy - considered the last great astronomer of the Roman era
1- He compiled all of the astronomical knowledge of the time into the Almagest
2- updated the geocentric model to include epicycles along an offset deferent from the Earth
3- wrote the Tetrabiblos, making him the father of modern Natal Astrology.
Who was Aryabhata?
Aryabhata - an Indian mathematician and scientist from the early 6th century.
He made strides in algebra and trigonometry
He estimated pi with high accuracy for the time, and pioneered usage of quadratic equations.
continuing Ptolemy’s usage of epicycles, detailing motions of the planets along the ecliptic.
What did Muhammad ibn Musa al-Khwarizmi write?
Muhammad ibn Musa al-Khwarizmi wrote Kitab Al-Jabr
What were the accomplishments of Ibn Yunus and Ibn al-Shatir?
updated errors in Ptolemy’s calculations using updated mathematics
What type of book did Abd al-Rahman al-Sufi publish?
published the Book of Fixed Stars, which was a compilation of stellar constellations.
Who was Ibn al-Haytham
considered the father of optics. He was the first to figure out the eyes take in light, rather than give it off. His work would later lead to the invention of the telescope.
What did Copernicus reintroduce?
Copernicus re-introduced the heliocentric model
Galileo Galilei
development of kinematics, friction, and even relativity
first scientist to turn a telescope to the heavens, where he witnessed the craters and valleys on the Moon in detail, discovered the four major moons of Jupiter (now called the Galilean Moons), mapped sunspots, and witnessed the phases of Venus, providing rock-solid evidence for the heliocentric model at last.
Who was Tycho Brahe?
Created the most accurate planetary data set of motion using his eyes
Referred to as the best “by eye astronomer”
Who did Brahe hire?
Jhoannes Kepler
What happened after Brahe died?
Kepler inherited all of his data and work and he created three laws.
What were the three laws that Kepler created?
1) Planets orbit the sun (sun at the focus)
2)Planets move fastest when they are close to the sun. Planets “sweep” out equal areas at equal times
3) p^2=a^3
p=planetary orbit (years)
a=average distance (Au)
What are the 6 accomplishments of Newton?
1- created the 3 laws of motion
2- invented calculus
3- Came up with the universal law of gravity
4- designed a new form of telescope
5- discovered light can be sent through a prism
6- Invented the ridges on coins
What are Newtons three laws of motion?
1- An object in motion will stay in constant motion unless acted upon by a force.
2- F=m(a)
F=force (N)
m=mass (kg)
a= acceleration
3- For every action there is an equal/opposite reaction
What is the equation to find momentum?
P=m(v)
Momentum=mass(velocity)
Conservation of angular momentum
essential for spinning
usually friction would stop the spinning
—–the longer it spins the slower it spins
What is the formula for the law of Gravity
Fg = G(M1)(M2) / r2
What did newton believe about light?
Corpuscule hypothesis for light, meaning that he believed light was made up of tiny particles.
What did Alessandro Volta and Michael Faraday begin understanding?
The phenomenon of electricity
What did Faraday study?
“study of magnetism” FEILDS
What did Faraday and James clerk Maxwell discover?
Electromagnetic fields.
lead to discovering that light was an electromagnetic wave.
What is wavelength?
the distance between the high points “crests” or the frequency.
What is the formula for the speed of the wave?
C=λf
speed of wave = wavelength (frequency)
What is the equation to find energy?
E=hc/λ
Energy(joules)=hc/wavelength
Inverse square law (light spreading)
F ∝ 1 / r2
What demonstrates known brightness?
Standard candles.
What are the 7 forms of electromagnetic waves
- Gamma Rays
- X-Rays
- Ultraviolet light (UV)
- Visible light
- Infrared light (IR; felt by humans as heat)
- Microwaves
- Radio Waves
What are “windows “
Some light passes and some doesn’t though the windows.
What is a spectrum
