Front Matter Free

This publication was originally developed as a support document for teachers who were part of the American Association of Physics Teachers - Physic Teaching Resource Agent (AAPT-PTRA) program. In that context, it was a publication meant to be used to support a PTRA’s outreach workshop.

The title for this publication is derived from the two position papers enclosed: Laboratory Activities as the Cornerstone of an Introductory Physics Course on page two and AAPT Position Paper on the Role of Laboratory Activities in High School Physics on page five. These position papers describe the function of the laboratory component of an introductory physics course. The sample laboratory activities included are not meant to be all-inclusive, cover every topic, or to be the only appropriate laboratory activities for introduction physics. They are intended to provide generative examples, and it is anticipated that anyone using these activities will augment and/or supplement them. The particular activities students are engaged in depends a great deal on the local conditions. See Note about Sample Laboratory Activities below.

A fundamental goal of any introductory physics laboratory program as stated in the Cornerstone position paper on page two is to, “… encourage students to ask question directly of nature, design methods of answering these question, and to interpret and understand the answers received.” This goal is also articulated by the “level of activities scale” developed by Mary Budd Rowe and described on page nine. Although the goal of science education is to get the student to Rowe’s level three, it is necessary to do some level 0, 1, and 2 laboratory activities in order to help the student develop the required skills and confidence. If students are given no assistance along the way, they will not likely reach level three. To use a physical analogy, most of us must crawl before we can run.

Thus, we believe that students cannot be provided with a “sink or swim” approach in reaching this goal of being an independent thinker. Planned laboratory activities need to incorporate an opportunity for creative extension toward higher levels of “independent” thinking and action. In an effort to approach the goal we use the concept of an “EXTRA”.

An “EXTRA” is an extension on the laboratory activity. An “EXTRA” idea can arise from the assigned laboratory activity, and must be based on a question raised by the student. Such a question could be related to the topic of the regular laboratory activity, and it must be one that can be addressed experimentally.

The following are a few examples of “EXTRAs.” During an experiment on lenses, it is common to move the object parallel to the principal axis of the lens and observe the effect this change in position has on the characteristics of the image. An “EXTRA” for this laboratory activity could be to move the object perpendicular to the principal axis and observe the effect this change of position has on the characteristics (notably the position) of the image. Another example. After student’s do an experiment with a simple pendulum, they could use a meter stick as a pendulum. Remember, that in order to become a level three experiment on the Rowe scale, the student must ask the question.

Other examples of level three activities consistent with Rowe level three include science fair projects, physics olympics events, and Fermi problems (see laboratory activity #99a).

How students report on their work is a matter of teacher preference. There are many ways to have students report on their work. Sample style sheets for three teachers are included on pages 11, 13 and 15,

The authors extend special thanks to John Layman, University of Maryland, Mario Iona, University of Denver, John Hubisz North Carolina State University, and George Taylor, Baylor School, Chattanooga, Tennessee for their support and suggestions.

High School teachers in the United States face a wide range of variables when they enter the classroom to teach physics. These variable include, but are not limited to, the following:

1. Class size,

2. Number of classes taught each day,

3. Class time available for laboratory activities,

4. Preparation time available for laboratory activities,

5. Equipment available for students to use while doing a laboratory activity, and

6. Student background in mathematics, degree of laboratory experience, and knowledge of physics.

The laboratory activities in this PTRA-PLUS Workshop Leader’s Manual have been used by the authors and were selected to accommodate a wide range of instructional styles and environments.

A teacher with four small classes (e.g., 15 to 25 students per class), with a double period class each week, and with a period each day for laboratory preparation might use laboratory activities like the following:

1. #5a -- Static Equilibrium,

2. #10b -- Motion of a Spring-and-Mass System,

3. #18a -- Images Formed by a Thin Converging Lens I,

4. #26a -- Magnetic Field Inside a Square Loop.

Another teacher with five classes each with over 35 students, no extended block of time for doing laboratory activities, and no preparation time may want a structured and short laboratory activity, with student reports that are consistent and thus easier to grade. This teacher might use laboratory activities like the following:

1. #1a -- Measurement of Speed,

2. #6a -- Speed of a Projectile,

3. #18b -- Images Formed by a Thin Converging Lens II,

4. #28a -- Determination of Planck’s Constant.

“Newton won a stunning victory for the intellect and the democratization of science because it became possible for students to have as much authority as teachers. By knowing proper methods, a youth could conduct an experiment whose results might confound his elder.”¹ 

A major task of a high school physics teacher is to help students acquire the skills and attitudes that will encourage students to ask questions directly of nature, design methods of answering these questions, and to interpret and understand the answers received. These skills and attitudes cannot be taught by lecture. Rather, they are learned by examples, by demonstrations, and by practice. A crucial element of this practice are the laboratory activities done by the student.

The division of science classes into “Lecture” and “Laboratory” is artificial, yet many students and teachers seem to regard the “Lecture” as the real science and the laboratory as merely some imposed formality. Such attitudes are similar to a football team watching a game film or listening to instruction on the proper method of blocking and considering that football!

It is not necessary to be in “The Laboratory” for students to do laboratory work. Any location, even outside the classroom, can be used to observe nature and to gather data which will lead to analysis and discussion of natural phenomena.

Similarly, equipment for laboratory activities need not be expensive. The “amount of” or “lack of” equipment should not affect the “hands on” or laboratory nature of a high school physics course. The equipment situation should only influence the particular laboratory activities which students might perform. In fact, the process of solving equipment problems will often teach the student as much physics as actually doing the laboratory activity after the equipment is working properly. Of course, time is another consideration when planning laboratory work. One interesting method, discussed by Clifford Swartz, of increasing the time spent on laboratory activities is by doing home laboratory activities.² 

Many benefits result from having a strong laboratory program as part of a high school physics course. Below are listed some of these benefits:

1. Developing or changing student's concept of physical phenomena

2. Providing concrete examples of physics

3. Illustrating the usefulness of physics

Using a variety of laboratory activities enables students to develop physics concepts by hands-on encounters with nature. This helps students crystallize physics concepts as well as demonstrate examples of how and why the concepts are important. The greater the range of laboratory activities and the closer these activities are to a student’s frame of reference, the higher the probability will be that the physics concepts will be retained by the student.

• 4.

  Learning skills

• 5.

  Gaining familiarity with a variety of measuring instruments

• 6.

  Learning to make reliable measurements

• 7.

  Understanding that measurements are never exact

• 8.

  Doing calculations based on significant digits

The skill of careful observation should be honed in the laboratory. Skills such as reading meters (avoiding parallax) and using common measuring devices such as multimeters should be learned. These are parts of physics which will most likely stay with students long after they have forgotten how to recite Newton’s Laws! A partial list of the skills that can be developed in a high school physics course include: measuring (using metric units, arbitrary units, and significant digits), calculating, error analysis, estimating, graphing, using references, writing clearly, et cetera.

• 9.

  Providing informal interaction

  TEACHER <---> STUDENT

  STUDENT <---> STUDENT

• 10.

  Providing active involvement

• 11.

  Generating interest

Working in the laboratory can provide an informal atmosphere, and also one in which students are actively involved in the learning process. The trick is to preserve the somewhat loose, informal setting; yet, keep the discussions on the phenomena being investigated. The informal interaction can increase trust between teacher and students and between students and other students, as well as result in better learning. Such settings also prove ideal in generating student interest.

• 12.

  Generating public relation and advertise physics

Chuck Lang³ and his colleagues have a laboratory activity in which rockets are fired in the football stadium. Besides being a laboratory activity where data are acquired and Newton’s laws are analyzed, this is an example of using an outside laboratory activity to generate interest and to advertise physics to future students.

• 13.

  Developing self reliance (“FATE-CONTROL”)

Students who do the laboratory activities begin to feel that physics is a subject over which they have control and that they can master it. One of the important roles of science instruction is to help students develop a sense of control over their environment.

• 14.

  Developing thinking and analysis

• 15.

  Developing creative thinking

• 16.

  Developing a sense of modeling

By seeing how the assumptions and theoretical idealization differ from actual experience, students will increase their understanding of what scientist call an idealized model. Physics students often learn to recognize the shapes of common mathematical models (i.e., function) to represent trends or relationships in data. Physics provides the content, the tools, and the understanding which can help answer many questions facing society today.

One of the beautiful aspects of using actual laboratory data is that the analysis can be pushed to the limit of the student’s ability. Starting with ideal situations (e.g., frictionless) and moving toward the actual careful observations, even very simple activities can be the subject of careful analysis touching on aspects outside the typical range of laboratory activities.

• 17.

  Providing career education

An important aspect of a high school education is giving students insight into various careers. Many people who use physics on the job, do measurements and solve problems by experimenting and modeling. If a student is only taught physics by reading and listening, the student will not be exposed to the type of activities many people do.

The items briefly mentioned above give an indication of the breadth and depth of the positive contributions that can be made by a strong laboratory program when it is an integral part of an introductory physics course. The best teachers are artists in the manner and mode of utilizing actual observations to help students learn physics.

• 18.

  Developing communication skills

• 19.

  Keeping accurate records

Many teachers have students write laboratory reports. Such reports give students an opportunity to practice the important skill of expository writing⁴. See page 13. Expository writing has been described as three parts “state what you are going to say”, “say it”, and finally “state what you said.” This is similar to the introduction, body and conclusion of a good laboratory report. Students can be given the opportunity to communicate their work in other ways (i.e., oral reports, videotape, poster display, et cetera)

“Newton won a stunning victory for the intellect and the democratization of science, because it became possible for students to have as much authority as teachers. By knowing proper methods, a youth could conduct an experiment whose results might confound his elders.”¹ Building on Galileo’s methods, Newton’s program of “experimental philosophy” firmly and successfully established the central method of physics, whereby inference from experience guides formulation of hypotheses, whose predictions are validated by experiment. Laboratory activities in high school physics provide experience with phenomena, a starting place for the systematic development of students’ ideas, and a testing ground for the predictive power of their reasoning.

Laboratory activities must be designed to engage students’ minds as well as their hands, so that students may acquire skills and confidence in their ability to:

• measure physical quantities with appropriate accuracy

• recognize factors which could affect the reliability of their measurements

• manipulate materials, apparatus, tools and measuring instruments

• provide clear description of their observations and measurements

• represent information in appropriate verbal, pictorial, graphical and mathematical terms

• derive inference and reason from their observations

• develop an ability to rationally defend their conclusions and predictions

• participate with their peers and their teacher in a cooperative intellectual enterprise

• articulate reporting of observations, conclusions and predictions in formats ranging from informal discussion to a formal laboratory report

• recognize those questions that can be investigated through experiment and to plan, carry out, evaluate and report on such experiments

“Theory and research suggest that meaningful learning is possible in laboratory activities if all students are provided with opportunities to manipulate equipment and materials while working cooperatively with peers in an environment in which they are free to pursue solutions to problems that interest them.”² The following teaching conditions enable this to occur:

• For students to acquire the manual and mental skills associated with learning physics, it is essential that they be fully engaged in laboratory activities. This requires sufficient equipment and laboratory stations for laboratory groups containing only two or three students.

• The number of students and of laboratory stations in a classroom must be small enough for the teacher to supervise the safety of student activities and to have sufficient time to actively work with each laboratory group.

• Where appropriate, laboratory activities should include equipment and phenomena that relate to the students’ world, such as toys, sports equipment, tools and household items, etc.

• The integration of laboratory activities with classroom work requires that students be able to move smoothly between their desks and the laboratory area and that there be sufficient space for equipment to remain set up. A classroom arrangement with space for desks, computers, and ample space for laboratory stations and equipment in the same room is ideal. At the high school level it is especially desirable for the laboratory area to be integrated with the classroom.

• Computers and modern instruments should be part of the laboratory equipment. Although excellent physics learning can take place using the simplest equipment, computers and measuring instruments incorporating modern technology can be powerful tools for learning physics concepts and developing skills of measurement, analysis and processing information. computer simulations should not substitute for laboratory experience, but may be used to supplement and extend such experience.

• Evaluation of student learning in physics should include assessment of skills developed in laboratory activities as well as the knowledge acquired during these activities. Test questions relating directly to laboratory work act not only to assess laboratory learning, but also communicate the importance of laboratory work to students.

• Effective employment of laboratory activities requires that teachers have adequate and convenient storage for equipment, a workspace with tools to repair, maintain or construct equipment and enough planning time in their schedules to maintain, set up and try out laboratory equipment prior to classes.

To maintain their skills and keep abreast of new developments in physics teaching, teachers need time, money, support and encouragement to participate in appropriate professional activities. These may include attendance at workshops and professional conferences; examining new laboratory equipment, curricula, texts and resource materials, and working and consulting with colleagues in schools and colleges and in the physics and engineering research community.

A common misconception is that physics and physics textbooks have existed since the beginning of time. This notion could not be further from the truth. Eve did not say to Adam one evening, “Honey, let’s write ourselves some physics texts so that Cain and Able will have something to do with all their spare time. They’ve been fighting so much these days.”

The information contained in your text represents the accumulation of knowledge of our physical world gathered over a span of hundreds of years. Of course, civilizations on this planet have been around for thousands of years. Why did it take so long for us to begin to comprehend the physical phenomena all about us? As ridiculous as this may sound today, prior to about the mid-sixteenth century, most people felt that it was not necessary to observe nature to understanding nature. Instead, the study of philosophy and religion were considered both necessary and sufficient for the proper understanding of nature’s ways. But a new, exciting philosophy was beginning to evolve. People were attempting to comprehend nature by first observing particular physical phenomena closely and then looking for regularities that appeared to be visible in these phenomena. Such a method of trying to discover these regularities of nature is called the EXPERIMENTAL METHOD.

Without the experimental method, there would be no physics…(You would be assigned to Study Hall instead). Over the last 400 years, countless experiments have been designed and performed all with the same basic intention: to comprehend the workings of the universe. And as long as the experiment is performed carefully and rigorously, it is difficult to refute the results. If Bronce Rockhead said to you one day, “Hey, a leaf falls faster than a rock”, you could teach him the error of his ways by simply designing and performing an experiment that disproves his assertion. (If Bronce is 6’4”, 250 pounds and tends to froth at the mouth when contradicted, it’s best to mail him the procedure of your experiment and let him perform it himself).

Also, though many people believe that physics is all mathematical, it should be mentioned that the role of the mathematics is help analyze the information (data) that has been gathered in an experiment and to present a discovered regularity as a mathematical statement; the simpler this statement the better.

Therefore, the aim of the laboratory activities or experiments as far as you’ll be performing them are:

1. To give you, the experimenter, personal contact with physical situations where controlled measurements are possible.

2. To investigate certain basic relationships.

3. To sharpen your comprehension of these relationships.

4. To increase your awareness that all physical facts and relationships must be scrutinized in the “laboratory.”

5. To appreciate the limitations on accuracy in every experiment.

6. To train you to observe, record, and analyze data.

In 1985 Mary Budd Rowe spoke with the first group of PTRAs in Flagstaff, Arizona. She presented two ideas about the Role of the Laboratory in science teaching. The first idea dealt with the concept of fate control. One of the fundamental tenants of education is to prepare an individual for adult life. In order to support a democracy, our nation needs adults who believe that they are a controlling part of the system and not a victim of the system. Mary Budd Rowe characterized an individual who feels that he has control and thus an impact on the results of an experience as a “Bowler"; however, an individual who feels that life is a random event over which he has no control is characterized as a “Dice Thrower.” The “Bowler” has a greater probability of making contributions to the system. On the other hand a “Dice Thrower” believes that personal actions have no impact, thus he is less likely to make a contribution to the system.

Mary Budd Rowe suggested that a science laboratory activity is an individual student’s work, and thus it is one of the experiences in school that can help an individual grow in a belief in their ability to control the outcome of an experience. The more a student gets an opportunity to do science as a scientist does science, the more likely the student will be to behave like a “bowler” as an adult. The “bowler’s” predominant attitude is that results are controlled by the “bowler”, and the “bowler” is the master of his own destiny.

The “dice thrower’s” predominant attitude is that life, including learning, is controlled by others. The “dice thrower” is a pawn in a game others are playing. The “dice thrower” lets others control his destiny. A democracy needs “bowlers.” Laboratory work in science classes can help develop the latent “bowler” in all our students.

Regardless of the type of science class or the nature of the particular students in that class, one of the most important goals is to emphasizes laboratory activities for all students.

The second idea presented by Mary Budd Rowe had to do with the “level” of a laboratory activity. As a teacher sets up the laboratory program, each laboratory activity can be classified according to the answer to the following three questions:

1. Does the student know the solution to the laboratory activity before starting?

2. Is the procedure for doing the laboratory activity prescribed by the laboratory manual or the teacher?

3. Is the problem given to the student?

If the answer to all three questions is yes, then the activity is a level 0. If the answer to only the first two questions is yes, then the laboratory activity is level 1. If the answer to only the first question is yes, then the laboratory activity is level 2. Finally if the answer to all three question is no, then the laboratory activity is a level 3. See table below:

Although the goal of science education is to get the student to level three, it is probably necessary to do some level 0, 1, and 2 laboratory activities in order to help the student develop. If the students is given no assistance along the way they will not likely reach level three. To use a physical analogy, most of us must crawl before we can run.

As an example to the levels for laboratory activities consider an activity to determine the acceleration due to the gravitational force. As a level 0 laboratory activity, the student would be

If the student does not know the answer, the activity could be a level one activity. If the student is just given the problem, then the student is free to select his own procedure and the activity become a level 2. At level 2 the student could use a pendulum, Atwood machine et cetera. In order to reach a level three activity the student must ask the question. This is the ultimate but of course difficult goal.

One method of approaching this goal is to use the concept of an “EXTRA.” An “EXTRA” is an extension on the laboratory activity. The “EXTRA” idea could arise from the assigned laboratory activity, and can be based on a question raised by the student. The question should be related to the topic of the regular laboratory activity, and must be answered experimentally.

The following are a few examples of “EXTRAs.” During an experiment on lenses it is common to move the object parallel to the principal axis of the lens and observe the effect this change in position has on the characteristics of the image. An “EXTRA” for this laboratory activity would be to move the object perpendicular to the principal axis and observe the effect this change of position has on the characteristics (notably the position) of the image. Another example. After student’s do an experiment with a simple pendulum, they could use a meter stick as a pendulum. Remember that in order to become a level three experiment on the Rowe scale, the student must ask the question.

Other examples of level three laboratory activities include science fair projects, physics olympics events, et cetera.

1. Some of you already have a great deal of mechanical skill and/or great mathematical prowess; others don’t. In this course it is assumed that each person can acquire acceptable competence in each of these skills with a modest amount of effort.

   You may come to an earlier laboratory session and just watch for a few minutes or you might, with permission, come in during a free period and carefully examine and try out the equipment. NEVER COME INTO THE LABORATORY AND HORSE AROUND. Such useless and sometimes destructive activity may be counted against your laboratory grade.

2. As you are working on the experiment, write down your observations as well as numerical data. Sometimes these written observations (or things that puzzle you) are more important than the numerical data. In other words, if a laboratory report contains only numbers and simple answers to simple questions you haven’t shown that you’ve really “gotten your hands dirty” in the laboratory.

3. Use a dark pen. Do not erase in your Laboratory Note Book. Draw a single line through the items to ignore.

4. UNITS! Include units with all measurements and calculated values.

5. In answering questions, USE COMPLETE SENTENCES!

• 6.

  Work only with a sharp pencil.

• 7.

  All data points should be clearly identified with either a circle or an X. In some cases the size of the circle indicates the variability associated with the measurement.

• 8.

  To make a graph easy to read and as accurate as possible, the graph should fill the entire sheet of graph paper. This is done by choosing the scale on each axis so that the graph fills the paper.

• 9.

  Choose a convenient scale for each axis. The scales on the two axes do not have to be the same, but once you have chosen a scale for an axis, each division along that axis must represent the same amount.

• 10.

  When a functional relationship is expected, draw the smoothest and simplest curve through or near the data points.

  • If you get a straight line as your best fit, find the slope of the graph and see if either the slope or some variation of the slope (like its reciprocal) has any physical meaning in the context of the laboratory activity. The units associated with the slope and the intercept of a graph often offer clues to the physical meaning of these quantities.

  • If the data do not seem to suggest a simple linear relationship, experiment by plotting other variation of the data such as the inverse of the ordinate versus the abscissa. Other methods include squaring one set of data, plotting the data on logarithmic paper; et cetera.

• 11.

  Label each axis of the graph with the quantity being measured and the units of measurement. Give each graph an appropriate title.

• 12.

  Be neat!

• 13.

  Show one sample for each type of calculation done to analyze the data. Do not show the arithmetic, but show how you arrived at the numbers. Include units in each step of the calculation. For Example:

  • Write the equation to be used. Clearly identify all symbols.

  • If appropriate show the algebraic manipulation of the equation to solve for the unknown quantity.

  • In this equation, substitute at least one set of numbers with units from the set of data.

  • Show the result(s) of arithmetic calculations with clear evidence of the proper processing of units.

• 14.

  Explain or discuss any apparent inconsistencies in your results. If the explanation is fairly simple, it might be best to repeat part or all of the experiment in an effort to remedy the situation. When it is not possible to repeat the experiment, a well-reasoned discussion could be satisfactory.

• 15.

  “EXCURSION” means just that. Excursions provide a stimulus should you care to do a bit more with a particular experiment you find interesting. Attempting to do an excursion WILL NOT replace shoddy work on the rest of the laboratory activity.

You will need a separate notebook for your physics laboratory activity reports. This notebook should be approximately 8.5 inches by 11 inches in size and filled with graph paper lined about 4 lines per inch. On the front cover write clearly and in large letters your name, the period for this class, and the words PHYSICS LABORATORY NOTEBOOK. Tape these two pages, called “PROCEDURES FOR MAINTAINING A PHYSICS LABORATORY NOTEBOOK” to pages 1 and 2. Also tape the notes called “GRAPHING TECHNIQUES” to page three and four. The next two pages of the notebook will contain a table of contents (one page for each semester). Use the following format for your table of contents:

PHYSICS LABORATORY NOTEBOOK … … … … … … … … … … … TABLE OF CONTENTS

After you receive a grade for a laboratory activity you should record the grade in the table of contents.

The formal laboratory report should contain the following parts:

The INTRODUCTION should give an overview of the goal(s) of the laboratory activity. You may include a purpose, a diagram of apparatus to be used, and a description of the procedures to be followed. In most cases this will be no longer than a single paragraph. Each laboratory report should start at the top of a new page and have the following heading:

DATA are usually recorded in a table. In addition you should record anything of interest that you observe while doing the laboratory activity. Never discard your original data. If your original data is written on a separate piece of paper, you can tape this paper into your laboratory notebook.

What you do with your observations and data is called ANALYSIS. This is often a set of calculations. The results of any calculations may be recorded in the same table that is used to record the data. Please use a double vertical line to separate the data columns from the calculation columns in the table. If a calculation is repeated several times it is not necessary to show every calculation, a sample calculation is sufficient. Another common form of analysis is graphing. After plotting a graph, information is gotten by reading the graph; by finding its slope, and intercepts; and at times by finding the area under the graph. You will be given a separate set of notes on graphing. You are encouraged to learn to use a computer to record, analyze, and display data. Copies of a program called GRAPHICAL ANALYSIS III are available that you are welcome to use during laboratory time.

The CONCLUSION is the final result of your laboratory report and usually reflects the ideas stated in the introduction. The conclusion may consist of specific numerical results (e.g., the density of water is 1.0 g/cm³) and/or general conclusions (e.g., density can be used to distinguish one material from another.) If the laboratory instructions contain any questions to be answered, the answers are generally included in or after this section of your report.

Many laboratory reports will be given two grades. One grade will be on the laboratory activity as outlined by the laboratory manual, handout, or the teacher. The second grade will be based on your “EXTRA.” An “EXTRA” is an extension on the laboratory activity. The “EXTRA” idea should arise from the assigned laboratory activity, and must be based on a question that you raise yourself. The question should be related to the topic of the regular laboratory activity, and must be answered experimentally. For the first few laboratory activities suggestions for EXTRAs will be discussed in class; however, as the year progresses, you will be expected to shoulder more and more of the responsibility for thinking of EXTRAs.

Some laboratory activities and reports may be turned in by a team of two students. Both students are responsible for doing the laboratory activity. The formal write up is done alternately in the laboratory notebook of the students in the laboratory team. Each student should update his/her own table of content for all laboratory activities. If this arrangement is not working to everyone’s satisfaction, the teacher or a student may request that laboratory reports be written up individually.

Laboratory reports must be turned in on the date due. In case of absence, I adhere strictly to the school policy that is in your student handbook. Reports turned in late without prior permission or after an unexcused absence will receive a grade of zero. Such a grade cannot be dropped before determining your average laboratory grade.

Please do not have any loose papers in your laboratory notebook. Any papers to be added to the notebook should be taped into the notebook. Please do not make it necessary to unfold a paper in order to look at it. When you submit your laboratory notebook for grading, please put a paper clip on the first page of the laboratory activity to be graded.

Your laboratory reports will be done on the laboratory sheet you receive as each laboratory activity is performed. One laboratory report may be turned in from each set of laboratory partners. Before you begin the activity, make sure you understand the purpose of the activity. As you do the activity fill in the data chart. Be sure you include units with your numbers.

After collecting all the necessary data, you are to do the calculations and answer any questions at home for homework. If there is time, you may begin to do them in class. Put your answers in the spaces provided and show appropriate calculations. Do not forget units.

When writing the conclusion you should remember to use parallel construction relative to your purpose. That is, if your purpose is to determine if there is a relationship between A and B; then your conclusion should state that the relationship between A and B is …. (name a specific relationship if found.)

Attach any graphs or charts to the laboratory sheet and turn everything in by placing it into your class folder on the due date.

NOTE TO TEACHERS: I teach in a situation with five science classes with no double periods and as many as 40 students in one class. I have used these procedures, in order to deal with the volume of laboratory “reports” for two laboratory activities per week.

One of the most common ways of displaying, organizing and analyzing experimental data is with a graph. The following is a set of suggestions for making effective graphs:

1. Each axis of a rectangular coordinate graph should include:

   • tick marks and numbers to show scale divisions used. It is not necessary to label every division (i.e., square) on a graph. Just label enough divisions so that it is easy to read the graph. Use round numbers on the tick lines. Never use numbers like 3.5 or fractions! The sample graph labels every fourth tick mark.

   • name of the quantity being plotted on that axis.

   • and in parenthesis indicate the unit of measurement [e.g., mass (grams) and volume (cm³)].

2. Choose a scale so that the graph will fill most of the page, but don’t use absurd scales to fill the page completely. It is better to have a graph fill the page rather than a graph that is too small. Use scales that are easily read.

3. Near the top of the graph write the title of the graph (e.g., “Mass versus Volume for Water in a graduated cylinder”) and if needed a key for the graph.

4. The independent variable (i.e., the variable you control) generally goes on the horizontal axis (i.e., X - axis). The variable on the Y - axis is then called the dependent variable. For the sample graph on the next page, the volume is considered to be the independent variable, while mass is the dependent variable. In this laboratory activity the student can select any volume of liquid, thus making volume the independent variable. The mass of the water and cylinder is then measured. The mass measured will depend on the volume selected and thus the mass is the dependent variable

5. If several sets of data or curves are graphed on the same page, make each of them distinctive by using different lines (e.g., solid, dashed, dotted, et cetera); or different outline symbols for data points (e.g., square, circle, triangle, et cetera); or different colors. Information about what each type of line, shape, or color represents should then be indicated in a key for the graph.

6. Surround actual data points with a circle, box, et cetera. The size of these guard circles, boxes, et cetera, may represent the variation of the measurement being plotted.

7. Be sure to check for possible “FREE DATA POINT(S).” A “FREE DATA POINT” is one that can be plotted without actually making a measurement. For example on a graph of mass versus volume for a liquid, there is a “FREE DATA POINT” at the origin. This free data point is inferred from the fact that there is a mass of zero when the volume of the liquid is zero.

8. If you have more than one page of graphs, number each graph so you can easily refer to it (e.g., “This conclusion is based on graph #2”).

9. If a functional relationship is expected, draw a line or curve for the graph. If a functional relationship is expected, you should not connect the data points with line segments (i.e., DO NOT connect the dots). You should draw a thin smooth curve or straight line that shows the trend of the data. Most computer generated graphs will determine a “regression line” for the data. A regression line is a line that is a statistical best representation of the function used to represent the trend of the data.

10. In practice the easiest graph to recognize and to draw is a straight line. Often the data are manipulated (e.g., inversed, squared, et cetera) and replotted in order to achieve a straight line. Using data points as a guide, draw a graph (i.e., interpolate) with a solid line. If appropriate, extend graph beyond the data (i.e., extrapolate) with a dotted line.

Today many students and classrooms have the ability to plot graphs using computers and/or graphing calculators. However, the basic format and principles for graphing remain the same. The graph below illustrates the techniques described above using a computer to do the graphing.

If the graph is assumed to be a straight line, one conclusion is that the mass of the water is proportional to the volume of the water. In fact the density of the water can be determine by calculating the slope of the graph. The mathematical expressions are:

The following is a listing of generic topics which could be the focus of some laboratory activity in a general introductory high school physics course. This list is not meant to be exhaustive, but rather suggestive of typical laboratory activities that can be done with high school students. The numbers of the sample laboratory activity direction sheets in this PTRA-PLUS workshop leader’s manual are correlated with the numbers in this list.

1. Investigation of varying position of an object

2. Investigation of average speed of a moving object by direct measurement.

3. Investigation of representations of motion using stroboscope and camera, photogates, ultrasonic motion detector, computer-interfacing, and/or recording timers.

4. Investigation of acceleration due to gravitational force on a freely falling object by direct use of an electronic timing device or recording timer.

• 4.

  Investigation of the sum of forces acting on a point at rest using a force table or force meters and strings.

• 5.

  Investigation of an unknown force(s) in a static balanced situation by application of Newton’s first law of motion.

• 6.

  Investigation of two-dimensional trajectories using a toy water pistol, spring gun, projectile ramp with carbon paper, and/or baseballs on the school playground.

• 7.

  Investigation of a relationship between force and acceleration or application of Newton’s second law of motion using an Atwood machine, air tracks or carts accelerated by hanging masses.

• 8.

  Investigation of the mass of an unknown object in a balanced system using torques or finding of the center-of-mass of a system.

• 9.

  Investigation of centripetal force using swinging stoppers and glass tubes, flying airplanes and/or toy car/buggies with a universal joint to make it go in circular motion.

• 10.

  Investigations of the variable(s) which affect periodic motion using spring-mass systems or pendulum with or without computer interfacing plots.

• 11.

  Investigation or verification of the conservation of momentum using dynamics carts, air track, air table with pucks, video disc, or ramps and marbles. Analysis of data for one and/or two-dimensional explosions and/or collisions.

• 12.

  Investigation of kinetic energy of a cart or pendulum using photogates, projectile motion data or kinematics equations applied to a cart on a ramp.

• 13.

  Investigation of energy conversions between potential and kinetic energy using penguins toy set, spring and mass system, pendulum and photogates, ramps and carts, loop-the-loop apparatus, ramps and marbles or pendulum cut at its lowest point. Investigation of percent efficiency of simple machines.

• 14.

  Investigation of the specific heat of a metal and/or the heat of fusion or heat of vaporization of a pure substance.

• 15.

  Investigation of wave behavior using ripple tanks, ceiling-hung Slinkies, Slinkies of various sizes, wave demonstrator apparatus, or videodisc. To include study of types of waves (e.g., longitudinal, transverse), propagation, wavelength, frequency, $v=fλ$⁠, reflection, refraction, diffraction and interference.

• 16.

  Investigation of a relationship between object position and virtual image associated with reflection of light from a flat mirror.

• 17.

  Investigation of refractive index using semicircular dishes filled with various liquids, triangular or square glass plates, straight pins and/or lasers.

• 18.

  Investigation of properties of images formed by curved mirrors and/or lenses.

• 19.

  Investigation of a relationship between illumination of light source and the distance of source using a photometer, shadows and/or light meters.

• 20.

  Determination of the wavelength of light using interference patterns using two-slit apparatus or a diffraction grating and/or determination of the diameter of a hair using thin film interference patterns from glass plates.

• 21.

  Investigation of emission wavelengths or identity of a gas using analysis of emission spectrum from high voltage discharge tubes and diffraction gratings. Investigation of characteristics of a single-slit, double-slit and multiple-slit patterns.

• 22.

  Investigation of the effects of static electricity upon electroscopes using insulators, pith balls, film cans, electrophorus or neon bulbs.

• 23.

  Investigation of electric fields in ripple tank filled with salt water.

• 24.

  Investigation of the relationship between resistance, voltage, and current in various resistor combinations (Ohm’s Law) using circuits, volt meter and ammeter, simple resistors, light bulbs and/or solid state diode.

• 25.

  Investigation of magnetic fields using bar magnets, iron filings, compasses, current-bearing straight length and/or coils of wire.

• 26.

  Investigation of the relationship between induced emf, coils of wires and bar magnets (e.g., Lenz’s Law.)

• 27.

  Investigation of radioactivity and the effect of distance, shielding or time (i.e., half life) upon radiation.

• 28.

  Investigation of Planck’s constant using LEDs.

• 29.

  Investigation of the mass of individual quantized particles used as a model of the Millikan’s experiment or a computer simulation.

• 98.

  Kinematics Games

• 99.

  Fermi Laboratory Activities

The American Association of Physics Teachers (AAPT) Physics Teaching Resource Agent (PTRA-PLUS) laboratory workshop is designed to be offered to between 20 and 30 participants in a time period of about six hours.

8:30 - 9:00 am REGISTRATION AND REFRESHMENTS

9:00 - 9:10 am DISTRIBUTE HANDOUTS The participants may keep and use the printed materials. See separate list of handouts on page 23.

9:10 - 10:10 am INTRODUCTION TO WORKSHOP Brief introduction and then participants progress at their own pace on the laboratory activity that they elect to do. The introduction may consist of one or more of the following:

1. Give an overview of the day’s activities using some of the following:

   • Discuss the role of laboratory activities in an introductory physics course. The major points from the discussion will be on the chalk board for reference during the workshop. In the afternoon it is instructive to compare these points to those listed in the two position papers on pages 2 and 5.

   • Discuss some general areas or concepts which should be explored by physics students in a one year introductory physics course. List the topics and compare the list to the one given on page 18.

   • Using the laboratory activities direction sheets, give a brief description of each of the experiments in the workshop manual. At the end of the introduction participants will choose one of these to do during the workshop.

   • Discuss the idea of FATE CONTROL and Mary Budd Rowe’s scheme for the four levels of experiments. (see page 9)

   • Discuss the concept of “an extra.” Each laboratory team is to develop an extra or extension activity related to the laboratory activity that they do. The concept behind “an extra” is to have the participants (or students) ask a question that can be answered by doing an experiment and then to do this extra or extension of the basic laboratory activity. As an example of an extra consider the typical laboratory activity for finding the relationship between the position of an object and its image formed by a converging lens. In the basic laboratory activity the object is moved parallel to the principal axis and the position of the image is noted. A possible extra would be to move the object perpendicular to the principal axis and then determine the position of the image.

2. After this introduction have one group of participants volunteer to take responsibility for one of the laboratory activities. It is not necessary to have every laboratory activity done. If no one volunteers to do a particular laboratory activity, just skip that activity.

3. Give the following assignment:

   • Do the laboratory activity as written and prepare to describe the strength and weakness of the laboratory activity in terms of the points presented earlier and/or in the position papers on pages 2 and 5. Participants may be encouraged to add other points to the position papers (see pages 2 and 5) presented in the morning.

   • Create and try an extension (i.e., EXTRA) or different method of showing a similar concept. Prepare to present and discuss the “EXTRA” ideas for extension of the laboratory activity that the participants did or that students might do.

   • Discuss the cost of the laboratory activity done versus its educational value, and consider cheaper methods which might show the same concept.

   • Discuss the advantages and/or disadvantages of doing the laboratory activity as a demonstration versus a hands-on laboratory activity.

   • Rate the laboratory activity using the Mary Budd Rowe’s scheme.

   • Discuss a way that the laboratory activity could be moved to a higher Rowe level.

   • Plan your presentation to include charts, graphs, et cetera, where appropriate. Include your results and places where teachers need to give specific instruction on safety and/or on possible errors.

   • Compare the three styles of laboratory reports described on pages 11, 13, and 15. Include the advantages and/or disadvantages of each.

10:10 - 10:30 PARTICIPANTS SELECT ACTIVITY AND PARTNER

10:30 - noon PARTICIPANTS WORK ON LABORATORY ACTIVITY Participants work in small independent groups of two or three teachers with assistance from workshop leader(s) as needed. By noon most of the participants will have gotten well started on the laboratory activity that they selected.

noon - 1:00 pm LUNCH AND INFORMAL DISCUSSION

1:00 - 1:15 pm REVIEW AND QUESTIONS Use this time to review the concepts covered in the morning, and answer questions that participants have about the morning activities.

1:15 - 2:00 pm FINISH LABORATORY ACTIVITIES During the early afternoon participants should be able to complete the laboratory activity (including “an extra”) they selected to do, and to plan a presentation for the rest of the participants on that laboratory activity. If the activity was completed in the morning session, the group may work on another activity in the afternoon.

2:00 - 3:30 pm PARTICIPANT PRESENTATIONS Each group of participants is to make a short presentation discussing the laboratory activity on which they worked. The presentation should be about 10 minutes, and include but not be limited to the following:

• Describe the strength and weakness of the laboratory activity in terms of the points presented earlier and/or in the position papers on pages 2 and 5. Participants may be encouraged to add other points to the position papers (see pages 2 and 5) presented in the morning.

• Prepare to present and discuss the “EXTRA” ideas for extension of the laboratory activity that the participants did or that students might do.

• Discuss the cost of the laboratory activity done versus its educational value, and consider cheaper methods which might show the same concept.

• Discuss the advantages and/or disadvantages of doing the laboratory activity as a demonstration versus a hands-on laboratory activity.

• Rate the laboratory activity using Mary Budd Rowe’s scheme.

• Discuss a way that the laboratory activity could be moved to a higher Rowe level.

• Plan your presentation to include charts, graphs, et cetera where appropriate. Include your results and places where teachers need to give specific instruction of safety or possible errors.

• Compare the three styles of laboratory reports described on pages 11, 13, and 15. Include the advantages and/or disadvantages of each.

• Present suggestions for improving or modifying the laboratory activity.

3:30 - 4:00 pm WRAP-UP This time could be devoted to a discussion of grading methods for laboratory reports, format for laboratory work or reports, how to manage large classes in the laboratory, et cetera. This time is open for any and all participants’ suggestions and/or comments. The participants should return all equipment to the proper location and complete the workshop evaluation form.

1. “Laboratory Activities as the Cornerstone of an Introductory Physics Course” position paper by Jim & Jane Nelson. See page 2.

2. “Good Laboratory Work” by George Taylor. See page 11.

3. “Procedures for Maintaining a Physics Laboratory Notebook” by Jim Nelson. See page 13.

4. “Graphing Techniques” by Jim Nelson. See page 16.

5. SIGNS:

   OBSERVATION ------->ANALYSIS -------->CONCLUSION

   DATA ------------->GRAPH ---------->EQUATION

   THE EXTRA … ???

   THIS IS A LABORATORY …

6. LABORATORY SHEETS FOR EACH OF THE ACTIVITIES USED IN THE WORKSHOP: It is not necessary to use the laboratory activities in the PTRA-PLUS workshop leader’s manual, you may wish to use other laboratory activities that you have equipment for and/or that you particularly like. Another format for the workshop is to have the participants bring equipment and handout for a laboratory activity. During the workshop participants switch equipment and do the laboratory activity brought by another teacher.

7. “Homely Physics” by Cliff Swartz, Editorial The Physics Teacher January 1985

8. “An evaluation of high school physics laboratory manuals” by Ernest Kuehl et. al., The Physics Teacher, April 1984

9. “The varieties of laboratory experience” by Cliff Swartz, Editorial The Physics Teacher, April, 1984

10. “PTRA High School Laboratory Survey” by Shelly Hamlin and Paul Hickman, The Physics Teacher, March 1987

11. “The Barometer Story” by Alexander Calandra.

12. SI: THE INTERNATIONAL SYSTEM OF UNITS, by Robert Nelson available from AAPT

13. TEACHING PHYSICS SAFELY booklet available from AAPT. Developed by the AAPT Committee on Apparatus, 1979

NOTE TO PARTICIPANTS: A good discussion of the purpose of the laboratory activities can be found in the AAPT Resource Kit for the New Physics Teacher, “III THE LABORATORY” pages 30 - 37.

The particular laboratory activities done during the workshop are not critical. The following are presented as a samples of laboratory activities that have been used during the PTRA national training sessions. The numbers for the activities are correlated to the section of this manual titled “Topics Commonly Addressed by Laboratory Activities in Introductory Physics.”

• 1a]

  Measurement of Speed -- In this activity students use a photogate to time a toy car as it passes through the photogate. They determine and compare the “instantaneous” speed to the average speed of the toy car.

• 2a]

  Average Speed Versus Final Speed -- In this activity students use a photogate to determine the speed of a toy car accelerating down an inclined plane. The speed at the end of its journey is compared to the overall average speed during the journey down the inclined plane. The activity is designed to show that an object starting from rest with a constant acceleration has a final speed that is twice the average speed.

• 2b]

  The Yellow Light Problem -- In this activity students investigate the timing of a traffic light to see if it is appropriately set. See Man Made World Laboratory Manual, ISBN 07-019506-4, published by McGraw-Hill Book Company, 1972. This activity provides a real world example of the use of kinematics.

• 3a]

  Speed and Acceleration -- In this activity the students use a photogate to determine the speed of a toy car at the top and bottom of an inclined plane and then use the definition of acceleration to determine the acceleration of the toy car. They then compare this acceleration to the acceleration determined using kinematics equation that relates distance traveled to time of travel.

• 3b]

  Acceleration Due to Gravitational Force -- In this activity the acceleration of a falling object will be determined by using a photogate and graphing. Two types of kinematics data can be illustrated (i.e., constant time intervals and constant position intervals).

• 5a]

  Static Equilibrium -- This activity is a variation of the typical static laboratory activity, and includes a method of measuring buoyant force. See article “Static Equilibrium”, by Jim Nelson in the December, 1985 issue of The Science Teacher.

• 6a]

  Speed of a Projectile -- In this activity, students determine the initial horizontal speed of a ball they throw off a high building or stadium as described by Yvette Van Hise in The Physics Teacher. See also “The Softball Trajectory: An Outdoor Lab” by Arthur Eisenkraft The Physics Teacher, May, 1985.

• 7a]

  Cart and “Falling” Object -- This is a variation on the laboratory activity of the cart being pulled by a hanging weight. Before doing the activity, students are asked to predict the acceleration of the cart with the expectation that they will use F = ma. However, most students do not include the mass of the cart in the mass being accelerated, and the measured acceleration will not be consistent with the predicted value. The laboratory activity is designed to help student understand the hanging weight laboratory activity by consideration of extreme cases (i.e., elephant pulling peanut and peanut pulling elephant). This laboratory activity is an excellent precursor to an laboratory activity using the Atwood machine.

• 8a]

  Force Distribution -- This activity is a life sized activity for students to investigate the forces and torques acting on the supports of a bridge.

• 9a]

  Centripetal Force alá PSSC -- Complete laboratory activity to find the relationship among

  • centripetal force,

  • radius of circle for object in uniform circular motion,

  • mass of object moving in uniform circular motion, and

  • frequency of circular motion.

  In this activity students do a more traditional laboratory activity (i.e., more detailed direction). This activity is an extension of a familiar laboratory activity but requires the student to vary each of the first three variables in the list above as a function of frequency. Several graphs are required. Before students do this laboratory activity they must know how to do a controlled experiment with several variables, to analyze data to find a functional relationship, and to combine several relationships into a single equation. Since several graphs are required, students could use a computer program to plot data.

• 9b]
  Centripetal Force Airplane -- Using a toy airplane moving in a horizontal circle with constant radius and speed, students are asked to make measurements so that the magnitude of the centripetal acceleration of the airplane can be determined first using

  $kinematics(i.e., ac=v2r)and then usingdynamics(i.e., ac=Fcm).$

  The student is asked to explain the measurements made and to compare the results. See article “Circular Motion Studies with a Toy Airplane”, by Frank Butcher THE PHYSICS TEACHER, December 1987

• 10a]

  Motion of a Simple Pendulum -- Typical simple pendulum laboratory activity with minimum directions. An introduction is provided for a physical pendulum. Timing can be done by using a light probe and a computer, photogate, or a stopwatch.

• 10b]

  Motion of Spring-and-Mass System -- In this activity students first do a Hooke’s law laboratory activity. Students then investigate the effect of amplitude, mass and spring constant on the frequency of a spring-and-mass vibrating system. This activity is an extension of a familiar laboratory activity but requires the student to vary each of the these three variables as a function of frequency. Several graphs are required. Before students do this laboratory activity they must know how to do a controlled experiment with several variables, to analyze data to find a functional relationship, and to combine several relationships into a single equation. Since several graphs are required, students could use a computer program to plot data.

  Students then investigate the effect of various combinations (i.e., parallel and series) of springs to determine their effective spring constant. This is analogous to capacitors connected in series and parallel combinations. A final part deals with the value of the spring constant versus length of spring.

• 12a]

  Hot Wheels and Energy -- In this activity students will compare the motion of a toy car down an inclined plane with the ideal frictionless motion discussed in most introductory text books. The laboratory activity suggests using a photogate to measures time.

• 13a]

  Prediction of Landing Position -- In this activity, the students predict the landing point of a pendulum bob if its string is cut at the bottom of its swing. Energy considerations are used to predict the point. Then the students try it.

• 14a]

  Newton’s Law of Cooling -- In this activity students will determine the final temperature of two identical cups of coffee. One cup with the cream added after two minutes and the other cup with the cream added after ten minutes to see which ends up being at the higher temperature after 12 minutes. This is a good activity for students the day before a school holiday. The temperature can be monitored by using thermistors and a computer or standard thermometers.

• 14b]

  Specific Heat of a Metal -- In this activity, metal shot (aluminum or copper will work), is used in a test tube with a buried thermometer. The test tube and contents are heated to 100° Celsius, and the heated metal is added to water in a calorimeter. Cheap calorimeter activity once the metal is purchased.

• 18a]

  Converging Lens I -- In this activity students will observe the properties of the image formed by a converging lens. This is a variation of the laboratory activity as done in the PSSC curriculum. Computer program available for analysis of data.

• 18b]

  Converging Lens II -- In this activity, students determine a relationship between Di and Do using convex lenses and candles. Typical laboratory book activity except the use of candles makes it more dramatic.

• 20a]

  Determination of Wavelength -- In this activity, students use Cornell gratings to determine the wavelength of red and blue light. They also compare single and double slit patterns.

• 21a]

  Atomic Spectra of an Unknown Gas-- In this activity, students work in a darkened room. All students observe the spectra, but because students are in different positions for each observer, only one student marks the position of each spectra line on the chalk board. One high voltage gas discharge tube apparatus will be enough for the class. A set of holographic diffraction gratings is very helpful.

• 24a]

  Ohm’s Law -- In this activity students set up their first circuit using meters and specially made resistors in heat sink boxes (not required), which do not require alligator clips and don’t burn hands.

• 24b]

  Voltage versus Current -- This activity requires the student to measure the voltage and current for an ordinary resistor, a light bulb, and a Zener diode. The characteristics of these three elements are then compared.

• 24c]

  Power Transfer -- In this activity students are asked to find the condition for maximum power transfer from a power supply to a load resistor. By adding an “internal resistor” to a power supply it can be made a variable in a typical power transfer laboratory activity. Students who have studied calculus can do a maximum minimum calculation to check the results of this activity.

• 25a]

  Electric Current and Magnetic Field -- In this activity, students investigate the magnetic fields around current bearing wires using small compasses.

• 26a]

  Magnetic Field Inside a Square Coil -- In this activity, students measure the magnetic field produced in a coil of current carrying wires. The magnetic field is compared to the earth’s magnetic field so that a relationship between the magnitude of the coil’s field and the current in the coil can be determined.

• 26b]

  Electromagnetic Induction -- In this activity, students explore various ways to induce a current using magnets and primary coils with changing magnetic fields. They are to determine and apply Lenz’s Law. Solenoids and Galvanometers are required.

• 28a]

  Determination of Planck’s Constant -- In this activity, students use red and blue LED’s to determine “h”. They only need to measure the minimum voltage to turn on the LED. The value of the wavelength of the emitted light is given. After doing the laboratory activity, students remember that to make blue light takes more voltage (energy per charge). Idea from Chicago’s AAPT Section.

• 29a]

  Milli-Can Experiment -- In this activity students will do a simulation of the Millikan experiment. This activity can be used as an introduction to the analytical approach used in the famous Oil Drop Experiment for finding the charge of an electron. See article in the January, 1980 issue of The Physics Teacher. Computer program available for students to collect data from a simulation of the Millikan experiment.

• 98a]

  Race Track Game -- In this activity students play a game to emphasize the two types of acceleration (i.e., acceleration along the path of motion and acceleration perpendicular to the path of motion). Race tracks can be reproduced on graph paper. A few examples are provided. A computer version of this game is available. For a sample game see page 109, SCIENTIFIC AMERICAN, January, 1973. For addition information, see following articles,

  “Physics of the game of racetrack by Vawter American Journal of Physics June, 1978;

  “Comments on ’Physics of the game of racetrack’” by Joyner & Smith American Journal of Physics, November 1979; and

  “Vector Racing by Thomas McDonald The Science Teacher, November, 1984.

• 99a]

  Fermi Experiments -- In this activity students will measure a large quantity by creative thinking and by making some reasonable estimate. See “Barometer Story” by Alexander Calandra. This is an example of a Fermi experiment. Other possibilities includes finding the volume of water in a swimming pool or the volume of air in a gymnasium.

• 99b]

  Density of a Liquid -- In this activity students measure the mass and the volume of two liquids. After plotting graphs of the mass of the liquids with and without the mass of the graduated cylinder versus the volume of the liquids, students are asked to explain the meaning of the slope and intercept of the resulting linear graphs.

High School teachers in the United States face a wide range of variables when they enter the classroom to teach physics. These variable include, but are not limited to, the following:

1. Class size,

2. Number of classes taught each day,

3. Class time available for laboratory activities,

4. Preparation time available for laboratory activities,

5. Equipment available for students to use while doing a laboratory activity, and

6. Student background in mathematics, degree of laboratory experience, and knowledge of physics.

The laboratory activities in this PTRA-PLUS Workshop Leader’s Manual have been used by the authors and were selected to accommodate a wide range of instructional styles and environments.

Consider a teacher with four small classes (e.g., 15 to 25 students per class), with a double period class each week, and with a period each day for laboratory preparation. This teacher might use laboratory activities like the following:

1. #5a -- Static Equilibrium,

2. #10b -- Motion of a Spring-and-Mass System,

3. #18a -- Images Formed by a Thin Converging Lens I,

4. #26a -- Magnetic Field Inside a Square Loop.

Consider another teacher with five classes each with over 35 students, no extended block of time for doing laboratory activities, and no preparation time. This teacher may want a structured and short laboratory activity, with student reports that are consistent and thus easier to grade. This teacher might use laboratory activities like the following:

1. #1a -- Measurement of Speed,

2. #6a -- Speed of a Projectile,

3. #18b -- Images Formed by a Thin Converging Lens II,

4. #28a -- Determination of Planck’s Constant.