Exam Review: Overview
Questions 1. What is the goal of science?
The major goal of science is to ask & answer questions about the physical universe that we live in. How is observation different from imagination? Observation gathers only what data is obviously true. Imagination can go anywhere—factual or not. Write an equation in words & then in symbols for the following sentence: The price of coffee beans is equal to the weight of the beans times the price of the beans per pound. Cost of Beans (C) = Weight of Beans (Wb) x Cost per pound (Cp) (C) = (Wb) x (Cp) . Write an equation in words & then in symbols for the following sentence: The change in the number of individuals in a population is equal to the difference between the number of births & deaths. Let: N = The change in the number of individuals in a population given length of time B = The number of births over a given length of time D = The number of deaths over a given length of time Equation: N = B – D. Describe the steps of the scientific method.
Experimentation (where, what, when_ b. Develop a Model (i. e. form a hypothesis)
Modify, Explain, Expand, & Interpret this Hypothesis
Test the Model
Be prepared to modify the hypothesis or reject it entirely
By what criteria might you determine whether a question might be answered suing the scientific method? Determine if an experiment can be set up to factually assess the question. If it appeals to the human belief, emotions, or feelings, then it is not scientifically testable.
Describe the difference between basic & applied research. Basic Research: the simple quest for knowledge & answers to questions, for no particular reason other than to find out how things work and to advance knowledge. a. t is unencumbered research; it has no agenda b. it has no mission other than to seek new knowledge & information Applied Research: This is research with a mission. Research that starts off with a particular goal, & strives to develop methods to reach that goal.
Discussion Questions 1. Which of the following statements could be tested scientifically to determine whether it is true or false?
Women are shorter than men. This can be scientifically tested b. Most of the Sun’s energy is in the form of heat energy. This can be scientifically tested c. Unicorns are now extinct. This can NOT be scientifically tested d.
Beethoven wrote beautiful music. This can NOT be scientifically tested e. Earth was created over 4 billion years ago. This can be scientifically tested f. Earth was created in a miraculous event. This can NOT be scientifically tested g. Diamond is harder than steel. This can be scientifically tested h. Baseball is a better sport than football viii. This can NOT be scientifically tested i. God exists. This can NOT be scientifically tested j. Vanilla ice cream tastes better than chocolate pudding. This can NOT be scientifically tested k. Men are better scientists than women. This can NOT be scientifically tested . Categorize the following examples as basic research or applied research. The discovery of a new species of bird.
Basic m. The development of a more fuel-efficient vehicle.
Applied n. The breeding of a new variety of disease-resistant wheat.
Applied o. A study of the ecological role of grizzly bears in Yellowstone National Park
Basic p. The identification of a new chemical compound
Basic q. The development of a new drug for cancer or AIDS patients
Applied r. The improvement of wind turbines for energy production.
Review Questions 1. With what ancient science is Stonehenge associated? Stonehenge functioned as a calendar by marking the seasons of the year & certain astronomical events (such as equinox &/or solstice). It did so by aligning stones around a central observation post so that they would align with astronomical events. Midsummer morning sunrise is aligned with the “Heel Stone. ” There are repetitive patterns in the astronomical movements of the sky. By carefully studying these movements, and marking them with sighting stones, the ancients could predict when certain events would reoccur.
Why was the Ptolemaic system accepted as an explanation of celestial motion for over a thousand years? What did it explain? What system challenged the idea that Earth was the center of the universe? The Ptolemaic system explained the apparent observations of movement in the sun, moon, and planets. It also fit into the religious doctrine of the time that believed that earth was the center of the universe and all creation. What were Tyco Brahe’s principal contributions to science? How did he try to resolve the question of the structure of the universe? Tyco Brahe constructed large brass tools for astronomical measurements.
These tools were built as accurately as possible. He even took into accound the expansion and contraction of the brass due to changes in temperature. He was able to make measurements with an accuracy of 2 min. of arc [quite good for the time]. In his time the telescope had not been invented. All observation was with the naked eye. Tyco gathered 25 years of extremely accurate data. What was Kepler’s role in interpreting Tyco Brahe’s data? Kepler was a brilliant mathematician. He had access to a large amount (25 years) of the most accurate astronomical measurement available to mankind (the data of Tyco Brahe).
It was Kepler that first demonstrated that the orbits of the planets around the sun were elliptical and not circular. Also, from this data came Kepler’s Laws of Planetary Motion. How did Galileo apply the scientific method to his study of falling objects? Galileo is especially known for his work in experimental techniques. He studied falling objects by doing repetitive experiments and making careful measurements. He is most famous for his work of bodies moving down an inclined plane. After his observations he would try to define his observations mathematically. Then he would test the hypothesis further by experimentation. . According to Newton, what are the 2 kinds of motion in the universe? How did this view differ from those of previous scholars? Newton described uniform motion & accelerated motion. Previous to Newton, scientists thought that moving bodies (i. e. planets) moved in circles & would continue moving in circles if left alone. Thus, for an object to move in a circle some outside force must be affecting it. Newton showed that there was Uniform Motion of an object traveling in a straight line at a constant speed. There was also Accelerated Motion which involves objects changing speed, direction, or both.
What is the difference between the constants g & G? g = the acceleration of gravity on earth. 8m/s2 G = Newton’s Universal Gravitational Constant 6. 67 x 10 -11 N-m2/kg2 8. What is the difference between weight & mass? Mass is the fixed amount of matter in an object. It never changes. (kilograms) Weight is the force by which gravity attracts the mass (Newtons & pounds)
Can you give an everyday example that illustrates the difference between acceleration & velocity? Which, if any, of the following objects does not exert a gravitational force on you?
The nearest star
A distant galaxy
The Atlantic Ocean
They all exert a gravitational force on you. Why don’t the planets just fly off into space? What keeps them in their orbits? The gravitational force of the Sun holds the planets in orbit, just as the gravitational force of the earth holds our moon in orbit. Why are observatories built as far away from major cities as possible? Observatories are built away from cities to avoid interference from city lights. What forces keep a pendulum swinging back and forth? Mechanical Energy is swapping both kinetic energy & potential energy back & forth.
If a person weighs 150 lbs, what does he weigh in Newtons? A person weighing 150 pounds would be equivalent to 667. 4 newtons 0. 454 kg/lb x 150 lb x 9. 8 newtons/kg = 667. 4 newtons Or 150 lb x 4. 43 newtons/lb = 664. 5 newtons 2. If your car goes from 0 to 60 mph in 6 seconds, what is your acceleration? If you step on the brake and your car goes from 60 mph to 0 in 3 seconds, what is your acceleration? Convert everything to Meters per second: [60 miles/hour x 1. 61 km/mile x 1000 m/km] divided by 3600 sec/hour Thus 60 mph = 26. 83 meters/sec This is Vfinal = 26. 83 m/sec V initial = zero cceleration = Vfinal – V initial 6 sec a = 26. 83 m/sec – 0 m/sec 4. 47 meters/sec/sec acceleration 6 sec Brake deceleration: a = 26. 83 = 8. 94 meters/sec/sec deceleration
Chapter 3 Review
Questions #1: What is the scientific definition of work? How does it differ from ordinary English use? Work is a force that operates over a distance. In common language, work can be done without moving something.
In science, something has to move. #2: What is a joule? What is the English system of units equivalent of a joule?
The joule is the amount of work done when a force of 1 Newton operates through a distance of 1 meter. Or, it is the amount of energy necessary to do 1 joule of work.
The English equivalent is the foot-pound. #3: What is the difference between energy and power? What is a unit of power?
How does speed relate to power? Energy is the potential to do work. Power is the rate at which work is the rate at which work is done. The watt is a metric measure of power. It is the speed at which work is done. It is 1 joule per second.
The horsepower also measures power. 1 horsepower is 550 foot-Pounds per second. #7: What does it mean to say that different forms of energy are interchangeable? Energy cannot be created or destroyed but it can be converted to one form or another. Examples: (1) The chemical energy of gasoline is converted to heat energy and mechanical kinetic energy in your automobile. (2) The sun’s radiant energy is converted to electricity by a solar cell, which can run a small motor, thus converting the electrical energy to mechanical energy, etc. , #10: Does the total amount of energy in an isolated system change over tie? Why or why not?
There is a finite and constant amount of energy in the universe. In any closed system experiment the total amount of energy never changes. It may be converted to different forms, but like an accountant’s ledger, it can all be accounted for. Problems #2: Which has more gravitational potential energy: a 200-kilogram boulder 1 meter off the ground a 50-kilogram boulder 4 meters off the ground, or a 1-kilogram rock 200 meters off the ground? Which of these can do the most work if all the potential energy was converted into kinetic energy? P. E. = mgh P. E. = (200 kg) (9. 8 m/sec2)(1 meter) = 1960 Joules P. E. = (50 kg) (9. m/sec2)(4meters) = 1960 Joules P. E. = ( 1 kg) (9. 8 m/sec2) (200 meters) = 1960 Joules ALL THE SAME #4: According to Einstein’s famous equation, E = mc2, how much energy would be released if a pound of feathers was converted entirely into energy? A pound of lead? (Convert pounds into kilograms) 1 lb is equivalent to 0. 454 kg on Earth c = speed of light = 299,792,458 m/sec E = mc2 E = (0. 454 kg) (299,792,458 m/sec)2 E = (0. 454 kg) (8. 9876 x 10 16) E = 4. 08 x 10 16 joules. It does not matter what the mass is made of, the energy conversion would be the same.
Chapter 4 Review
Questions #2: What is specific heat capacity? Which heats more quickly, a kilogram of water or a kilogram of copper? Why? It takes longer to heat the Kg of water because it requires more heat energy than the copper. This is shown by the specific heat of water which is 1. 00 and the specific heat of copper which is 0. 092. It requires 1000 calories to raise the kilogram of water by each degree C, while it requires only 92 calories to raise a Kg of copper by each degree. #3: What are the 3 different ways by which heat is transferred? How are these three phenomena occurring while you are reading this book?
Heat can be transferred by: conduction (generally in solids) convection (usually in liquids & gases) radiation (works best in a vacuum #4: What is the difference between temperature & heat? TEMPERATURE is the “intensity” of heat. It actually represents the kinetic energy of the molecules and atoms within the substance. It is measured in degrees. HEAT is the true measure of thermal energy. It is measured in calories. #6: Is there a directionality to the flow of heat? Yes. Heat can only from higher temperatures toward lower temperatures #8: Describe three common temperature scales. What fixed points are use to calibrate them?
The three common temperature scales are Fahrenheit, Celsius, & Kelvin. Fahrenheit: Based approximately on the living conditions on the surface of the planet. It approximates a temperature range between the coldest days & the hottest days which is 0 def. F to 1000 deg. F. Water freezes at 32 deg F & boils at 212 deg F Celsius: based on the properties of water. 0 deg C is the freezing point of water & 100 deg C is the boiling point. (at 1 atmosphere of pressure (i. e. sea level) Kelvin: the absolute energy scale. 0 deg Kelvin is the point where no thermal energy exists at all (we have never achieved this in a lab)
In the Kelvin scale water freezes at 273 deg K & boils at 373 deg K #11: What is entropy? Give an example of a situation in which entropy increases. Can the entropy of an isolated system decrease? If so, how? Entropy: a measure of disorder in a system * Natural systems, left to their own devices will tend to increase in entropy (i. e. becomes more disordered) * Example of decreasing entropy is found in the formation of ice cubes from water in your freezer; the extraction of salt from seawater, the mining and smelting of gold from the earths crust. But notice that we have to expend energy in all of these examples.