scientific reasoning final review - homework questions; dr.hershey
The more precisely the position of a particle is measured, the less precisely its momentum at that time can be known, and vice versa. This is called
Heisenberg's uncertainty principle
Who discovered that the luminosity of a Cepheid variable is correlated with its pulsation rate?
Henrietta Leavitt
In classical mechanics, mass was a fundamental property—a property that was not explained in terms of other properties. According to the Standard Model, however, mass is not a fundamental property. The mass of an elementary particle comes from its interaction with the _ field.
Higgs field
The sun's energy comes from a process called "_ burning," a series of nuclear reactions that fuse hydrogen nuclei together to form helium.
hydrogen burning
As ice melts in a cup of warm water, the entropy of the system
increases
When an object with mass is accelerated close to the speed of light, its relativistic mass
increases
When the net force on an object is zero, the object's motion is
inertial
According to Galilean relativity (Galileo's theory of relativity), the same laws of motion hold in all _ reference frames.
inertial reference frames
If two atoms have different numbers of neutrons but the same number of protons, they are different _ of the same element.
isotopes
Using spectroscopy to determine what types of atoms are most abundant in stars and galaxies throughout the universe, astronomers have determined that light elements (hydrogen and helium) are far more abundant than heavy elements. Cosmologists consider this an important piece of evidence supporting the Big Bang model because, according to the model, the period of nucleosynthesis that began shortly after the Big Bang
lasted only a few minutes, so there wasn't enough time for large nuclei to form.
In a Hertzsprung-Russell diagram, young stars in their hydrogen-burning phase lie along a curve called the
main sequence
Which of the following are fundamental properties?
mass and charge
All three of the following claims seem true, yet it is logically impossible for all three to be true: 1) systems always obey the same fundamental laws, regardless of whether they are being measured, 2) the Schrödinger equation is a fundamental law of nature, and 3) when you measure a system that was in a superposition, you get a single result rather than going into a superposition yourself. This paradox is known as the
measurement problem
There are an estimated 100 - 200 billion galaxies in the observable part of the universe, and each of those galaxies contains millions or billions of stars. Our own galaxy is called the _.
milkyway
According to the theory of evolution, new genes and alleles are created by
mutations
Charles Darwin suggested that biological evolution is driven by
natural selection
The natural elimination of hereditary traits that do not promote survival and reproduction, and the preservation of traits that do, is called
natural selection
According to the prevailing theories, stars and galaxies formed from the gravitational collapse of huge clouds of gas called _.
nebulae
When a carbon-14 atom undergoes beta minus decay, what is the isotope of the resulting atom?
nitrogen-14
When a nuclear weapon is detonated at ground level, it can throw tons of radioactive soil and debris into the atmosphere. This radioactive debris, which may rain down hundreds of miles away, is called nuclear _.
nuclear fallout
The region of the universe close enough for its light to travel to us in less than 13.8 billion years is called the
observable universe
In order for one event to cause another, according to special relativity, the two events must:
occur within each other's light cones
In quantum mechanical models of atomic structure, probability density functions represent "fuzzy" wave-like states called:
orbitals
Electromagnetic waves act a bit like particles in some respects. (For instance, they come in particle-like "packets," they can exert forces on things, and they even behave as though they have momentum—despite the fact that they have no mass.) A "particle" of light or electromagnetic radiation is called a _.
photon
After a new star forms, most of the remaining dust and gas in the star's vicinity is cleared away by stellar _, which consists of fast-moving particles streaming from the star's surface.
wind
The smallest amount of an isotope needed for a sustained nuclear chain reaction is called the "_ mass" of that isotope.
"critical mass"
According to James Clerk Maxwell's theory, light consists of
waves of oscillating electric and magnetic fields
Suppose an alien spaceship were to zoom past the earth at a constant velocity close to the speed of light. Which of the following is/are predicted by special relativity?
--- According to Earth's reference frame, the alien's clock is running slower than ours. --- According to the alien's reference frame, our clock is running slower than hers. --- From our perspective, the alien's meter stick is shorter than ours. --- From the alien's perspective, our meter stick is shorter than hers.
Which of the following phenomena are predicted and explained by Einstein's general theory of relativity?
--- As light travels away from a massive object, its wavelength increases. --- Waves of curvature travel through spacetime itself. --- The elliptical orbits of planets gradually precess. --- Starlight bends as it passes near the sun. --- Atomic clocks run slightly slower at low altitudes and slightly faster at high altitudes.
List four types of evidence for the theory of evolution and briefly describe one objection that has been raised against each type of evidence.
1. There is documented evidence of cases of biological evolution occurring. objection: although this might support microevolution (a change happening to an already existing species or organism) it does not support Macroevolution, the emergence of an entirely new organs and structures. 2. Genetic recombination, mutation, and natural selection are plausible mechanisms by which life could evolve, and there is abundant evidence that all three of these processes do occur. objection: finding ways that life COULD evolve does not show that life DID evolve. also, some features of living organisms are Irreducibly complex. 3. An organism's DNA is usually similar to that of its supposed ancestors and also to its evolutionary cousins. Also, genetic similarities are found in pseudogenes. objection: just because an organism has similar DNA does not imply common descent. it may point to a common designer. also, there is a danger of circular reasoning here. 4. Fossils provide striking and quite a bit of evidence that life has evolved quite a lot over the past several billion years. objection: some church folks say that the fossils are from that flood that Noah was in.
In the selection from Seeking God in Science, Monton provides another formulation of the fine-tuning argument. (His version of the argument differs from the version discussed by Moreland and Craig but is similar to the version I gave on the PDF handout.) What are the three premises of the fine-tuning argument, according to Monton?
1. the fundamental constants that are involved in the laws of physic which describe our universe are finely tuned for life, in the sense that if some of the constants had values outside some narrow range then life could not exist. 2. If God created the universe, we would expect it to be life-permitting. 3. the universe is life-permitting.
According to the reading, there are numerous ways in which Christian theology helps to justify and motivate scientific inquiry. In your own words, briefly explain three of those ways.
1.) Since in the Christian faith, their God controls everything because he made everything it gives zero room to doubt physical laws because we can assume it will hold true in all mathematical endeavors because God has control over all. 2.) Again, in this religion, since the Christian God created everything the way it is you can not just make discoveries about the laws of nature by just thoughts and reasons, you must conduct specific procedures of experimentation. 3.) If human beings are created in the image of the Christian god (smart and sensible) then we can assume the things we study and investigate will also be intelligent if done so carefully.
Galileo made several important discoveries that supported the heliocentric model of the universe over the geocentric model. Name three such discoveries and give a brief (1 or 2 sentences) explanation of how each of these discoveries supported the heliocentric model.
1.) the location of venus In geocentric models, there is no way that venus could be further away than the sun is yet galileo disproves this by viewing venus's phases and showing how we can see it illuminated like we see the moon fully illuminated. 2.) the moon is not perfectly spherical This goes against the geocentric theory because in the geocentric theory Aristotle claims that all other things in the sky (like the moon) is perfect. 3.) the sun has sunspots This also defeats the everything in the sky in perfect geocentric theory because the sunspots indicate a different temperature, therefore, making the surface temperature not consistent through out the sun.
When the air and the ground are different temperatures, heat energy that is transferred from one to the other can be used to generate electricity by powering a heat engine. This is in fact done in geothermal power plants throughout the world. If the temperature of the air is 300 K (about 27 ºC, or 80 ºF) and the temperature of the ground is 270 K (about -3 ºC, or 26 ºF), what is the maximum possible efficiency of a heat engine that uses the air as its high-temperature reservoir and the ground as its low-temperature reservoir? _
10 %
_ newtons of force are required to accelerate a 4 kg object at a rate of 3 m/s2
12
During which two centuries did the so-called "scientific revolution" take place?
16th century (1500s) AND 17th century (1600s)
How much work is done when lifting a 2 kg object 10 meters upward against the pull of the earth's gravity? (Hint: You'll find a similar example on this page.) Be sure to include the correct units in your answer. _
196 J
What is the gravitational potential energy (relative to the earth's surface) of a 2 kg object located 10 meters above the ground? Be sure to include the correct units in your answer. _
196 J
Which of the following is the nuclear equation describing the fusion of hydrogen-1 and hydrogen-2 to form helium-3?
1H + 2H → 3He
When lithium burns (i.e. combines with oxygen), how many lithium atoms combine with each oxygen atom? Hint: Study the examples on the page about chemical reactions before attempting questions 7 and 8. _ lithium atoms combine with each oxygen atom
2 lithium atoms combine with each oxygen atom
Suppose a rocket is traveling away from the earth at 270,000 km/s (90% the speed of light). According to Einstein, if we shine a laser beam past the rocket, how fast will the beam of light be traveling in the rocket's frame of reference?
300,000 km/s (100% the speed of light)
What is the kinetic energy of a 6 kg object moving at a speed of 4 m/s? Be sure to include the correct units in your answer. _
48 J
Which of the following is a balanced chemical equation describing what happens when lithium burns, i.e., when atoms of lithium metal (Li) combine with oxygen molecules (O2)?
4Li + O2 → 2Li2O
Suppose Mendel breeds some true-breeding tall pea plants together with true-breeding short plants, to produce hybrid offspring (all of which will be tall, because the tall allele is dominant). He then breeds those first-generation hybrid offspring together with more true-breeding short plants, to produce a new set of offspring. Note that this is different from the experiment described in the reading. In that second generation of offspring, what percentage of the plants will be tall? (Hint: Use a Punnett square to figure out the answer.) _ percent of the second-generation offspring will be tall.
50%
When a horizontally polarized photon hits a linear polarizing filter that is oriented 45 degrees from horizontal, what is the probability that the photon will pass through the filter? _
50%
How many of the electrons in an oxygen atom are valence electrons? _
6
When Mendel bred true-breeding pea plants with different traits, the first generation of hybrid offspring always had the dominant trait. When he bred those hybrids together, however, _ percent of their offspring had the dominant trait and _ percent had the recessive trait.
75% 25%
Oxygen is the sixth element in the second row of the periodic table. When an oxygen atom is not chemically combined with anything, how many electrons does it have total? _
8
What happens to a charged object when it moves through a magnetic field?
A sideways force is exerted on it (perpendicular to its direction of travel).
What conclusion did Newton draw from his "spinning bucket" thought experiment?
Acceleration is an absolute (non-relative) quantity.
Which scientist concluded that aether doesn't exist?
Albert Einstein
Who explained the photoelectric effect by suggesting that light comes in particle-like packets of energy called "quanta"?
Albert Einstein
A(n) _ particle consists of two protons and two neutrons. (This particle is identical to the nucleus of a helium-4 atom.)
Alpha
Which of the following temporal asymmetries are explained by the second law of thermodynamics?
Apples fall from a tree to the ground, but apples don't leap off the ground and fly upward into the tree. Ice cubes melt in warm water, but they don't spontaneously freeze out of warm water. Air leaks out of a punctured tire, but punctured tires don't spontaneously re-inflate. A hockey puck slows down as it slides across an icy rink; it doesn't speed up.
Who was first to suggest that the earth orbits the sun?
Aristarchus of Samos
When a system is measured, which fundamental law of quantum mechanics gives the probabilities of the various possible measurement outcomes?
Born's rule
In what way(s) are mass and electric charge similar?
Both are fundamental properties. AND Each is associated with a fundamental force.
In the assigned reading from Philosophical Foundations, Moreland and Craig present a different version of the fine-tuning argument, which they call the "teleological argument." What are the two premises of the teleological argument based on cosmic fine-tuning, according to Moreland and Craig?
Can the cosmic fine-tuning be plausibly attributed to physical necessity? 1. The fine-tuning of the universe is due to either physical necessity, chance or design. 2. It is not due to physical necessity or chance.
The Big Bang theory was first proposed by
Catholic priest named Georges Lemaître
In which of the following ways did Dalton's theory of atoms differ from the views of the ancient Greek atomists Leucippus and Democritus?
Dalton suggested that each chemical element consists of a different type of atom.
On pages 84-86, Monton criticizes Richard Dawkins' reply to the fine-tuning argument. Which of the following is not one of the two objections he raises against Dawkins' line of reasoning?
Dawkins cannot prove that the "multiverse hypothesis" really is simpler than the "God hypothesis."
In their famous 1887 experiment, Michelson and Morley tried to measure the speed of Earth's motion through aether using perpendicular beams of light. What did the result of their experiment imply?
Earth isn't moving through aether at all.
Which scientist hypothesized that atomic nuclei consist of positively-charged protons and uncharged neutrons?
Ernest Rutherford
On page 486, Moreland and Craig discuss John Leslie's "fly on the wall" analogy. The point of the analogy is to support which of the following claims?
Even if it is possible for there to be life-permitting universes with wholly different physical laws, this possibility is irrelevant to the fine-tuning argument.
True or false: According to the Standard Model, forces can be exerted instantaneously at a distance.
False
True or false: From the time of the early church until the 19th century, Christian apologists and theologians all agreed that the days of the Genesis creation story were ordinary 24-hour days.
False
True or false: If two events occur outside each other's light cones, there is an absolute fact of the matter (all reference frames agree) about which event occurred first.
False
True or false: Some theories of relativity in physics support relativism, the view that there are no absolutes.
False
True or false: The gravitational constant (G) is the rate at which free-falling objects accelerate near the surface of the earth (9.8 m/s2).
False
True or false: The more particles a system contains, the more likely it is that a low-entropy state will occur by chance.
False
True or false: The temperature of an object is the total amount of heat (thermal energy) it has.
False
Which scientist challenged the Aristotelian theories of motion and gravity?
Galileo Galilei
The farther away a galaxy is, the faster it is moving away from us. This correlation is called:
Hubble's law
As an apple falls from a tree, its gravitational potential energy is converted to kinetic energy. When the apple lands on the ground, what happens to most of that energy?
It is converted into heat
Which scientist hypothesized that an atom consists of a positively charged sphere with negatively charged electrons scattered through it?
J.J. Thomson
Which scientist formulated the first general theory of evolution, proposing that evolution is driven by environmental forces?
Jean-Baptiste Lamarck
Which scientist used Tycho Brahe's data to calculate the shape of the planetary orbits?
Johannes Kepler
Who proved that it is impossible for any non-chancy theory of local "hidden variables" to give all of the same predictions as quantum mechanics?
John Bell
Which scientist discovered the law of multiple proportions?
John Dalton
Astronauts on the International Space Station (ISS) don't feel Earth's gravitational pull, because:
The ISS is in orbit, so it is essentially free-falling toward Earth.
Lithium is the first element in the second row of the periodic table (atomic number 3). Will a lithium atom gain an electron or lose an electron when it reacts with oxygen?
Lithium will lose an electron.
Our galaxy belongs to an enormous collection of over 100 clusters of galaxies, spreading over a region of space more than 100 million light years across. This collection of galaxies is called the
Local Supercluster
In which of the following ways did Einstein's special theory of relativity differ from Lorentz's theory?
Lorentzian relativity says that the aether's reference frame is the only frame in which measurements of distance and time are objectively correct; but according to Einstein, all inertial reference frames are equally valid. AND Lorentz had suggested that length contraction and time dilation are physical effects caused by an object's motion through aether; but according to Einstein, times and distances are just relative quantities which differ from one reference frame to another.
The relationships between electric and magnetic fields are described by
Maxwell's equations
Which of the following conclusions did Ernest Rutherford draw from the Geiger-Marsden gold foil experiment?
Most of the mass of a gold atom is concentrated in a positively-charged nucleus.
Which law of classical mechanics was replaced by Einstein's idea that the worldline of any inertially-moving object follows a geodesic through spacetime?
Newton's first law of motion
Special relativity is incompatible with which law of classical physics?
Newton's law of universal gravitation
In which of the following ways did Copernicus's model of the universe differ from Ptolemy's?
Ptolemy's model placed the Earth at the center, but the Copernican model placed the Sun at the center.
Given that the universe began in a condition of extremely low entropy, it is unsurprising that its entropy has been increasing, because the random motion of microscopic particles tends to increase the entropy of a system. The fact that the universe began in such a low-entropy state, however, is difficult to explain. Which physicist estimated that the probability of the universe starting that way by chance is smaller than the ratio of the volume of a proton to the entire volume of the visible universe?
Roger Penrose
According to the Rutherford model, electrons orbit the nucleus of an atom like planets orbit the sun. There were several problems with this model of atomic structure. Which of the following was not one of the problems mentioned in the reading?
Rutherford's model couldn't explain why atoms sometimes emit alpha particles.
The hypothesis that all living organisms on Earth have a common ancestor is called
universal common descent
Near the surface of the moon, the gravitational acceleration of a falling object is about 1.6 m/s2. How much does a 10 kg rock weigh on the moon? The rock weighs _ newtons on the moon.
The rock weighs 16 newtons on the moon.
The first row of the periodic table only has two elements (hydrogen and helium). This is because:
The rows of the periodic table correspond to electron shells and the first shell only has room for two electrons.
Suppose a 5 kg rock is moving toward the right with a velocity of 3 m/s, and a 4 kg rock is moving toward the left with a velocity of 2 m/s. What is the total momentum of the two-rock system? The total momentum is _ kg m/s toward the _.
The total momentum is 7 kg m/s toward the right .
Suppose the two rocks collide and bounce off of each other. (Assume no external forces are acting on the rocks; the only forces on them are the forces they exert on each other during the collision.) Which of the following claims is true?
The total momentum of the two-rock system will be exactly the same as it was before the collision.
What do gamma rays, x-rays, radio waves, microwaves, and visible light have in common? (Indicate all that apply)
They all travel at the same speed. AND They are all forms of electromagnetic radiation (electromagnetic waves).
What happens when a proton and an antiproton collide?
They annihilate each other and are converted into light.
Many different interpretations of quantum mechanics are empirically equivalent. This means:
They give exactly the same predictions about all observations that could ever be made, including any observations we might make in the future.
Each cell in a living organism's body contains a copy of the same set of DNA molecules, called the organism's
genome
True or false: Although Monton is an atheist (he doesn't find the fine-tuning argument compelling enough to persuade him to believe in God), he admits that the fine-tuning argument for God's existence is somewhat plausible.
True
True or false: By comparing the spectral lines of light from younger (more distant) galaxies with the light from older (nearer) galaxies, astronomers have discovered that heavier elements become more abundant as galaxies age.
True
True or false: Carbon-12 and carbon-14 (two isotopes of carbon) behave the same way in chemical reactions.
True
True or false: Conditions of high entropy are much more likely to occur by chance than conditions of low entropy.
True
True or false: Due to the force of gravity, the earth is accelerating toward the sun
True
True or false: Each chemical element (type of atom) absorbs and emits light with a unique set of colors.
True
True or false: Einstein's special theory of relativity implies that a spaceship traveling faster than light would also be going backwards in time: a passenger on board would see effects happen before their causes.
True
True or false: Electrons, which have a negative charge, produce magnetic fields as they orbit the nucleus of an atom.
True
True or false: If two events occur inside each other's light cones, there is an absolute fact of the matter (all reference frames agree) about which event occurred first.
True
True or false: Large stars use up their nuclear fuel more quickly than small stars do.
True
True or false: Ludwig Boltzmann, Hans Reichenbach, and numerous others physicists and philosophers have suggested that the directionality of time (the distinction between past and future) might be explained in terms of entropy and chance.
True
True or false: Most laws of physics are time-symmetric, which means that they make no distinction between past and future: any process they allow to happen forwards is also allowed to happen backwards.
True
True or false: Most of the mass of an atom consists of potential energy from the nuclear strong force.
True
True or false: Prior to the publication of Galileo's Dialogue Concerning Two World Systems, in which he expressed the views of Pope Urban VIII through the mouth of a character named Simplicio ("the fool"), the Pope had been Galileo's friend and supporter.
True
True or false: Quantum field theories, which form the basis of the contemporary Standard Model of particle physics, are consistent with special relativity but not with general relativity.
True
True or false: Some electrical power plants are powered by heat from the nuclear fission of uranium and other radioactive elements.
True
True or false: The antiproton (the proton's antiparticle) has the same mass as the proton, but it has negative charge instead of positive charge.
True
True or false: To determine how fast a galaxy is moving toward or away from us, astronomers measure the blueshift or redshift of its light.
True
True or false: To estimate the age of our solar system, scientists use a technique called radiometric dating to analyze meteorites—rocks that have fallen to Earth from space.
True
True or false: When beams of protons collide inside the Large Hadron Collider (LHC), some of their kinetic energy is converted into new particles that didn't exist prior to the collision.
True
True or false: Your shoes are pulling on the planet Neptune with a (very weak) gravitational force.
True
Which of the following is not a method used to measure interstellar distances?
Use radar to bounce radio waves off of a star and time how long it takes for the radar echo to return
Kinetic energy can be converted into which of the following other forms of energy?
gravitational potential energy chemical potential energy electromagnetic potential energy heat
beta radiation
high-energy electrons emitted during radioactive decay
The entropy of a system is a measure of
how many possible microstates are compatible with its thermodynamic condition.
Which of the following has the most heat?
a frozen lake
Which one of these objects does not follow a geodesic through spacetime, according to general relativity?
a rock lying on the ground
In a spacetime diagram, a curved worldline represents an object that is
accelerating
The paired forces in Newton's third law
act on different objects.
Hereditary traits are determined by units of heredity that we call genes, each of which comes in multiple varieties corresponding to various possible traits. These different forms of a gene are called
alleles
According to the presently accepted theory, most of the heavy elements that comprise our planet were formed by nuclear fusion reactions that occurred in
ancient supernovae
The half-life of carbon-14 is the amount of time it takes for
approximately half of a large collection of carbon-14 atoms to decay
Opponents of the teleological argument sometimes allege that the design hypothesis is no better than the chance hypothesis. They claim that in order for the design hypothesis to explain fine-tuning, the existence of the designer (God) must also be explained. However, Moreland and Craig argue that "this popular objection is based on a misconception of the nature of explanation." (p. 490) To illustrate their point, Moreland and Craig use an analogy involving
astronauts finding traces of intelligent life on some other planet
At the center of our Milky Way Galaxy is a supermassive _ with a mass approximately 4 million times the mass of the sun.
black hole
gamma radiation
electromagnetic waves (light) with extremely high energy (high frequency, short wavelength)
Which subatomic particles were discovered first?
electrons
Electrons and other subatomic objects aren't really particles in the familiar sense: they are quite different from visible particles such as grains of sand or specks of dust. They behave like particles in some ways, yet they also act like waves. The double-slit experiment illustrates this wave-particle duality. In what way do electrons behave like particles in the double-slit experiment, and in what way do they behave like waves?
electrons behave like particles in the double slit test when you test just one electron then it makes a single dot on the film once it is put through, just like a particle would. electrons behave like waves in the double slit test when a large group of electrons is fired to the slits then an interference pattern, that shows up for waves, appears.
Which type of galaxy is believed to form from the collisions of old galaxies that have already used up most of their interstellar gas?
elliptical galaxies
In the previous chapter, we saw that the total momentum of a system is conserved—that is, it doesn't change—so long as no external forces act upon the system. What other quantity is also conserved in a closed (isolated) system?
energy
Which mysterious quantum phenomenon seems to violate the principle of locality, as pointed out by Einstein and his colleagues Podolsky and Rosen?
entanglement
As explained in the reading, events that occur inside a black hole cannot be regarded as simultaneous with events outside: from the perspective of an outside observer, it seems that events inside a black hole must occur infinitely far in the future! The sphere-shaped boundary between the interior and exterior of a black hole is called its _ horizon.
event horizons
As discussed in the reading, some Christians reject the theory of evolution completely. Others reject only certain aspects of evolutionary theory, sometimes proposing ways of modifying the theory to render it compatible with their understanding of scripture. Still others fully accept the theory and suggest that God ordained natural processes to produce the varieties of biological life. The view that God used evolutionary processes to create the diverse forms of biological life is called _ creationism.
evolutionary creationism
Thousands of planets have been discovered orbiting other stars in our Milky Way Galaxy. Planets outside our solar system are called _.
exoplanets
The fact that no extraterrestrial civilizations have been detected despite the apparent likelihood of their existence is called the _ paradox.
fermi paradox
Nuclear _ occurs when a neutron strikes an atomic nucleus and breaks it apart.
fission
When atomic nuclei collide and join together to form a larger nucleus, this is called nuclear _.
fusion
Arrange the following parts of the electromagnetic spectrum in order from highest energy (highest frequency, shortest wavelength) to lowest energy (lowest frequency, longest wavelength).
gamma rays x-rays ultraviolet light visible light infrared light microwaves radio waves
Within a protoplanetary disk, bits of dust stick together in clumps, like hailstones forming in a storm cloud. When a clump accumulates enough matter to pull in dust by its own gravity, it is called a _; and when it grows so large that its interior begins to melt, it is called a _.
planetesimal protoplanet
When radon-220 undergoes alpha decay, what is the isotope of the resulting atom?
polonium-216
The moon is approximately 380,000 km away from Earth, on average, so it takes a little more than one second for its light to reach Earth. If a "shooting star" (small meteor) strikes the Earth and a large asteroid hits the moon exactly 1 second later, the spacetime interval between the meteor strike and the asteroid impact is:
positive
What previously unknown particles did Carl Anderson discover in his cloud chamber experiments?
positrons
Which of the following are composite particles—i.e., particles comprised of more than one elementary particle? Indicate all that apply.
protons, hadrons, baryons
According to the Standard Model (the currently accepted theory of particle physics), all matter in the universe is comprised of which two types of elementary particles?
quarks AND leptons
Some atoms have an unstable nucleus, which may spontaneously break apart or transform in a process called
radioactive decay
In sexual reproduction, alleles can be combined in various ways to produce traits that differ from the traits of either parent. This process is known as
recombination
When the sun runs out of hydrogen in its core, a new fusion reaction will ignite in a thin layer of hydrogen surrounding the core, and the sun will become a
red giant
All type Ia supernovae have approximately the same luminosity: about 5 billion times brighter than the sun. For this reason, type Ia supernovae are excellent standard candles, allowing astronomers to calculate distances to galaxies up to ten billion light-years away. To estimate the distance to galaxies even farther away than that, astronomers measure _ caused by the expansion of space and use Hubble's law to estimate the distance.
redshift
Some quantities in physics depend on an arbitrarily-chosen frame of reference. For example, an object's velocity, its momentum, and its kinetic energy vary depending on which reference frame is chosen. Quantities that vary from one reference frame to another are called _ quantities.
relative quantities
If two events occur outside each other's light cones, the events have _ separation.
spacelike
Our own galaxy is a(n) _ galaxy.
spiral galaxy
Which phenomenon would not occur if the "aether drag" hypothesis were correct?
stellar aberration
When the state of a physical system doesn't correspond to any definite value for a measurement variable (like position or velocity), the system is said to be in a _ of different possible values for that variable.
superposition
As explained in the reading, cosmologists use Einstein's general theory of relativity to retrodict how the size and density of the observable universe has changed over time. By calculating the average density at any given time in the past, they can also estimate the average _ at that time and then use the Standard Model of particle physics to predict what sorts of particles existed at that time.
temperature
The sound of a car seems to change pitch as it drives past. This shift in frequency is due to
the Doppler effect
Which interpretation of quantum mechanics claims that when you measure a system in a superposition, you go into a superposition too, and each "copy" of you sees a different result?
the Everett interpretation
Born's rule seems to imply that whenever we measure something, the world suddenly stops obeying which of the following laws of physics?
the Schrödinger equation
Which fundamental law of quantum mechanics describes how the state of a system (represented by a wave function) changes over time?
the Schrödinger equation
According to the Big Bang model, the universe was filled with glowing hot hydrogen plasma for hundreds of thousands of years after the Big Bang, until it expanded and cooled enough for electrons to attach to protons, forming hydrogen gas. Which of the following is believed to be leftover light from that glowing plasma?
the cosmic microwave background (CMB)
Which fundamental force holds atoms and molecules together in chemical bonds?
the electromagnetic force
alpha radiation
the emission of particles that consist of two protons and two neutrons
Imagine a rocket far away in deep space, where the gravitational pull from stars and planets is negligible. If the rocket speeds up with a constant acceleration of 9.8 m/s2, standing inside the rocket's capsule will feel exactly like standing on Earth. According to Einstein, this is no coincidence: gravity and acceleration feel the same because they are the same! The claim that gravity and acceleration are physically the same is called:
the equivalence principle
What are explained by Newton's laws?
the fact that heavy objects and light objects fall at the same rate the fact that planets have (approximately) elliptical orbits the ebb and flow of the ocean's tides
The strength and direction of the electric field at any given point in space is defined in terms of
the force that would be exerted on a charged particle located at that point
Several hypotheses have been proposed to explain the low-entropy condition of the early universe: the inflation hypothesis, the cyclic universe hypothesis, and the multiverse hypotheses. Please provide a brief description of each of these hypotheses.
the inflation hypothesis gives the idea that an unknown force expanded and stretched out the structure of space rapidly st the dawn of time. the cyclic universe hypothesis gives the idea that the universe exists through periods of low and high entropy in a cycling pattern. the multiverse hypothesis gives the idea that there is potentially an infinite number of universes and we just happen to be in one of the ones that started out with low entropy.
Moreland and Craig point out that the anthropic principle does not explain why the universe is finely-tuned for life unless we also assume:
the many worlds hypothesis
What does the atomic number of each element on the periodic table represent?
the number of protons in the nucleus
Why is the sky blue?
the sky is blue due to the effects of diffuse scattering. Since colors like blue and purple have more scattering happening in comparison to warmer colors which do not have as much scattering happening in our atmosphere. the more atmosphere the light from the sun has to go through the more cool coloration our sky will have.
According to Einstein's special theory of relativity, all inertial reference frames agree on:
the spacetime interval (timelike, lightlike, or spacelike separation) between two events
Which fundamental force holds together the protons and neutrons in the nucleus of an atom?
the strong force
In Monton's "dartboard" analogy (p. 77), each point on the dartboard represents a possible set of values of the fundamental constants (or a "possible universe" in which the fundamental constants have those values), and the bull's-eye region of the dartboard represents
the tiny range of possible values that are life-permitting
In Einstein's famous equation E = mc2, what does the "E" represent?
the total energy an object contains
What does the mass number of an isotope represent?
the total number of protons and neutrons in the nucleus
Which interpretation of quantum mechanics says that wave function collapse is caused by the consciousness of an observer?
the von Neumann-Wigner interpretation
According to Bohr's model, the energy of an electron orbiting at any given distance from the nucleus corresponds to
the wavelength of a standing wave that could form around the nucleus at that distance AND the kinetic energy of a particle moving just the right speed to stay in orbit at that distance
The most powerful nuclear weapons use the heat from a uranium or plutonium fission bomb to ignite a nuclear fusion reaction in a tank of hydrogen or lithium hydride fuel. A device like that is called a
thermonuclear weapon
In the Hafele-Keating experiment, four clocks were flown around the world on commercial airliners, first eastward and then westward. The clocks ran slower when flown eastward, and they ran faster when flown westward. Explain why.
these results happened because relativity of time is more pronounced at long distances. the westbound aircraft stayed in an almost inertial reference frame while the earth rotated beneath it. since the earth rotates eastward, the clocks on that plan experienced greater acceleration in comparison to the clock on the plane flying westward.
If it is possible to get from one event to another traveling slower than the speed of light, the two events have _ separation.
timelike seperation
Potassium (atomic number 19) is more reactive than lithium (atomic number 3), even though both are in the same column of the periodic table and have the same number of valence electrons. Explain why potassium is more reactive.
to begin, potassium is closer to the bottom left which elements tend to get more reactive the closer they get to the bottom left (or top right). also, the more electrons that an atom has, the pull from the nucleus is less strong. this makes the atom seem almost no charge and electron with greater energies have escaped with less difficulty.
