Physics Assignment One

One way to triangulate the distance to many remote objects, such as stars, is to observe the shifts in their location relative to more distant background objects. This apparent shifting of an object's location with respect to the background objects is known as parallax. Parallax is represented in the figure, where the top image shows the parallax shift that is observed along a baseline that runs from one side of Earth to the other. The bottom two images show what the observer sees from opposite sides of Earth. Using triangulation, the distance to the object can be calculated with simple trigonometric relations. Use the figure to determine how the measured parallax changes in each of the following situations: increases, decreases, remains the same 1. As the distance to the object increases, parallax _. 2. As the size of baseline increases, parallax _. 3. As the distance to background objects increases, parallax _.

1. As the distance to the object increases, parallax decreases. 2. As the size of baseline increases, parallax increases. 3. As the distance to background objects increases, parallax remains the same.

What is the test for whether a hypothesis is scientific or not? A hypothesis is scientific if it is possible to prove it wrong. A hypothesis is scientific if it can be written as an equation. A hypothesis is scientific if it is possible to prove it right. A hypothesis is scientific if the appropriate scientific body says it is.

A hypothesis is scientific if it is possible to prove it wrong.

In daily life, we see many cases of people who are caught misrepresenting things and who soon thereafter are excused and accepted by their contemporaries. How is this different in science? A scientist who disagrees with current theory is never allowed to be a scientist again. A scientist who makes a mistake is never allowed to be a scientist again. A scientist who proposes a hypothesis that is eventually disproven is never allowed to be a scientist again. A scientist who lies in a scientific publication will suffer professional excommunication.

A scientist who lies in a scientific publication will suffer professional excommunication.

Briefly, what is science? Science describes the order in nature and the causes of that order. Science is a way of knowing about the world and making sense of it. Science creates testable laws and theories. All of the above.

All of the above.

What is the role of equations in this book? Equations are interesting side notes about scientific concepts. Equations are for plug-and-chug calculations. Equations are guides to thinking and show connections between concepts. Equations will be derived to make you understand science.

Equations are guides to thinking and show connections between concepts.

Geometric reasoning can be used to measure distances both on Earth and in space. Surveyors on Earth and astronomers both use the geometric technique of triangulation to determine the distances and sizes of remote objects. In order to determine the distance using the triangulation method, a few key geometric components must be known. Once the baseline and the sightline angles are determined, then the distance can be calculated with simple geometric reasoning. In the figure below, label the essential components used to triangulate the distance to the tree located on the opposite side of the river (assume the baseline remains constant).

Explaination: Surveyors use triangulation to measure distances to objects on Earth. The same technique can also be used to determine the distance to nearby astronomical objects. Astronomers use Earth's diameter as the baseline in the triangulation method to measure distances to planets and other objects in our solar system.

The geocentric model, in all of its complexity, survived scientific scrutiny for almost 1,400 years. However, in modern astronomy, scientists seek to explain the natural and physical world we live in as simply as possible. The complexity of Ptolemy's model was an indicator that his theory was inherently flawed. Why, then, was the geocentric model the leading theory for such a long time, even though the heliocentric model more simply explained the observed motions and brightness of the planets?

False. The complexity of the geocentric model was appealing to most ancient astronomers. True. From Earth, all heavenly bodies appeared to circle around a stationary Earth. True. The geocentric model conformed to both the philosophical and religious doctrines of the time. True. Ancient astronomers did not observe stellar parallax, which would have provided evidence in favor of the heliocentric model. True. The heliocentric model did not make noticeably better predictions than the geocentric model.

Two competing models attempt to explain the motions and changing brightness of the planets: Ptolemy's geocentric model and Copernicus' heliocentric model. Sort the characteristics according to whether they are part of the geocentric model, the heliocentric model, or both solar system models. Retrograde motion is explained by epicycles. This model is Sun-centered. Planets move in circular orbits and with uniform motion. This model is earth-centered. The brightness of a planet increases when the planet is closest to Earth. Retrograde motion is explained by the orbital speeds of planets. Epicycles and deferents help explain planetary motion.

Geocentric This model is Earth-centered Retrograde motion is explained by epicycles Heliocentric The model is Sun-centered Reterograde motion is explained by the orbital speeds of planets. Both geocentric and heliocentric Epicycles and deferents help explain planetary motion Planets move in circular orbits and with uniform motion The brightness of a planet increases when the planet is closest to Earth

Copernicus's heliocentric model and Ptolemy's geocentric model were each developed to provide a description of the solar system. Both models had advantages that made each an acceptable explanation for motions in the solar system during their time. Sort each statement according to whether it is an advantage of the heliocentric model, the geocentric model, or both. Planetary orbits and motions based on Greek ideologies of perfect form and motion Rooted in widely accepted religious beliefs regarding Earth's place in the universe Predicated planetary positions accurately over relatively short time periods. Explained planetary motions and brightness changes most simply.

Heliocentric Explained planetary motions and brightness changes most simply. Geocentric Rooted in widely accepted religious beliefs regarding Earth's place in the universe Both geocentric and heliocentric Planetary orbits and motions based on Greek ideologies of perfect form and motion Predicated planetary positions accurately over relatively short time periods.

Why are students of the arts encouraged to learn about science and science students encouraged to learn about the arts? Scientists need to learn how to write and writers need to learn what is impossible to do according to science. Knowing both the arts and sciences makes for a wholeness in the way we view the world. Scientists need to learn to draw and artists need to learn how to solve equations. Scientists need to relax by viewing art and artists need the discipline of learning science.

Knowing both the arts and sciences makes for a wholeness in the way we view the world.

Must people choose between science and religion? No, scientific and religious beliefs are incompatible. No, religion and science are essentially the same. Yes, religion and science are completely antithetical. No, there is no contradiction in being scientific and religious in one's thinking.

No, there is no contradiction in being scientific and religious in one's thinking.

Clearly distinguish between science and technology. Science is applied technology. Technology can be helpful or harmful, while science is only helpful. Science gathers the knowledge that technology uses for practical purposes. Technology solves problems, whereas science creates them.

Science gathers the knowledge that technology uses for practical purposes.

What test can you perform to increase the chance in your own mind that you are right about a particular idea? Read up on the validity of the axioms you assumed when you crafted your idea. Write down your own idea as an equation. See if you can state the objections of your opponents to their satisfaction. Write a clear explanation of your idea and share it with everyone to gather objections.

See if you can state the objections of your opponents to their satisfaction.

Why did Aristarchus choose the time of a half Moon to make his measurements for calculating the Earth -Sun distance? The Earth, Moon, and Sun formed an acute triangle at that time. The Earth, Moon, and Sun formed a straight line at that time. The Earth, Moon, and Sun formed a right triangle at that time. The Earth, Moon, and Sun formed an obtuse triangle at that time.

The Earth, Moon, and Sun formed a right triangle at that time.

How does the Moon's diameter compare with the distance between Earth and the Moon? The Moon's diameter is 1/110 the distance between Earth and the Moon. The Moon's diameter is 1/2.5 times the distance between Earth and the Moon. The Moon's diameter is equal to the distance between Earth and the Moon. The Moon's diameter is 1/3.5 times the distance between Earth and the Moon.

The Moon's diameter is 1/110 the distance between Earth and the Moon.

What are the circular spots of light seen on the ground beneath a tree on a sunny day? These are blurry images of the point of light that is the Sun. These are images of holes formed by gaps between leaves. These are images of holes in leaves. These are pinhole images of the Sun.

These are pinhole images of the Sun.

Which of the following are scientific hypotheses? Tides are caused by the Moon. Chlorophyll makes grass green. Earth rotates about its axis because living things need an alternation of light and darkness.

Tides are caused by the Moon. Chlorophyll makes grass green.

In daily life, people are often praised for maintaining some particular point of view, for the "courage of their convictions." A change of mind is seen as a sign of weakness. How is this different in science? When a famous scientist restates a law, then the old law must be abandoned. Once a scientific law is discovered, it never changes, so you must change your mind to believe it. When a scientist finds evidence that contradicts a law, then the law must be abandoned. Scientific laws are decided to be true by majority vote.

When a scientist finds evidence that contradicts a law, then the law must be abandoned.

Once the distance to a remote object is determined via triangulation, one can measure the angular diameter of the object and convert that to an actual diameter. For relatively small angular diameters of a few degrees or less, the corresponding linear diameter can be approximated using the following expression: Diameter=Distance×(Angular Diameter)(57.3 degrees) The figure below illustrates that the diameter of a remote object increases with its distance and its measured angular diameter. Consider the Moon and Sun. Their angular diameters are both equal to about .5 degree. If the Sun is roughly 400 times more distant than the Moon, how much bigger is the Sun's diameter than the Moon's? about 400 times bigger about 800 times bigger about 400 times smaller

about 400 times bigger

Listed following are a series of statements that each make a claim. Classify these as either testable by accepted methods of science or non-testable by accepted methods of science. Be sure to note that this question does not ask whether a statement would pass or fail a test; it only asks whether it is testable in principle. There will be a solar eclipse next Tuesday at 11 am Hurricane Katrina was an act of God Bacteria acquire resistance to antibiotics through changes in their DNA Vince Young is the greatest quarterback of all time People born under sign of Sagittarius are twice as likely to be teachers as anyone else Mars once had liquid after on its surface Earth orbits the Sun every 365.25 days

testable by science There will be a solar eclipse next Tuesday at 11 am Bacteria acquire resistance to antibiotics through changes in their DNA People born under sign of Sagittarius are twice as likely to be teachers as anyone else Mars once had liquid after on its surface Earth orbits the Sun every 365.25 days not testable by science Hurricane Katrina was an act of God Vince Young is the greatest quarterback of all time