Laboratory Policies




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Earth and Space Science

Laboratory Manual


PHSC 3004


1st Edition


©John D. Leyba

2007


logo5

Table of Contents


Laboratory Policies 3

Lab Reports 4

Lab #1 Measurements of Length, Mass, and Density 5

Lab #2 Using Microsoft® Excel to Make a Graph 9

Lab #3 Observing the Various Phases of the Moon 13

Lab #4 Hubble’s Law 15

Lab #5 Humidity 19

Lab #6 Minerals 23

Lab #7 Radioactive Materials 26

Lab #8 Ten Day Forecast 29



Laboratory Policies



1. Safety is the number one priority in the laboratory. All students will be expected to follow all safety rules at all times. Students will be required to provide their own safety glasses for certain laboratory experiments. Any student caught violating safety rules/procedures will be severely penalized up to and including an F in the course.


2. Each student will be required to use their own laboratory manual to record data.


3. Brief (no more than 5 pages) lab reports are to be written for each experiment. See the "Lab Reports" section for more details.


4. It is the student's responsibility to be properly prepared for each laboratory experiment. This includes reading the appropriate material and planning lab work in advance. The instructor reserves the right to give “pop quizzes” over laboratory materials if students do not appear to be properly prepared for lab.


5. If you break it, you buy it. Each student will be required to pay for any broken lab equipment.

Lab Reports



Lab reports (no more than 5 pages per report) will be formally written and turned in for each lab. Each student is required to use a word processor and/or spreadsheet for their lab reports. Students will be working in groups in the lab but each individual must complete their own lab report based upon the group's findings/results.


Each report must contain the following sections: Title of Experiment; Date of Experiment; Brief Introduction (no more than five sentences); Required Materials; Raw Data; Calculated Results (please show at least one example calculation for each type of calculation. This may be handwritten); and Conclusion. Lab reports will be graded based upon the proper format, use of correct calculations including the use of the proper formulas; the proper use of units; and the answers given to questions asked in the labs. Lab reports are due one week after the completion of the lab. Late lab reports will be accepted up to two days after the due date of the assignment. Late lab reports (without a valid excuse) will be penalized 50%. Lab reports turned in more than two days late will receive no credit.

Lab #1 Measurements of Length, Mass, and Density



Purpose: To learn how to make measurements of length with a ruler, vernier caliper and micrometer, measure mass using a balance, and determine the density of an object.


Apparatus: ruler, vernier caliper, micrometer, graduated cylinder, balance, and various objects to be measured.


Introduction: Physical measurements are used to determine many physical quantities including time, length, mass, etc. The precision of the measurements depends on the type of instrument that is used, the technique used to calibrate it, and the person making the measurements.


The least count of a measurement device is the smallest subdivision or unit that is marked on the scale of the device. One can usually estimate a measurement to 1/10 of the least count. Some instruments have scales that will allow much more accurate estimates of 1/10 of the least count, such as a vernier caliper.


A simple method used to estimate precision is the spread of the data. For two or more measurements done in an identical fashion, the spread of the data is calculated by taking the difference between the highest measured value and the lowest measured value.


A vernier caliper is a device used to measure lengths directly to hundredths of a centimeter. We can then use this device to estimate to thousandths of a centimeter. The vernier caliper consists of a fixed ruler with two scales (English and metric) and a sliding mechanism. The sliding mechanism also has two scales (English and metric). Both the fixed and sliding parts have jaws attached. The upper parts of the jaws are used to measure the inside diameter of an object while the lower parts of the jaws are used to measure the outside diameter of an object. Your instructor will demonstrate how to use and read a vernier caliper.


A micrometer is another device used to measure length. A micrometer can directly measure lengths to 0.01 mm and can be used to estimate lengths to 0.001 mm. The key components of a micrometer are the anvil (against which the object to be measured sets), a moveable spindle, barrel, thimble, and ratchet. The spindle can be opened or closed using the ratchet mechanism. The dimension of the object being measured is read from the scales on the barrel and thimble. Your instructor will demonstrate how to use and read a micrometer.


Mass and volume are extensive properties. This means that these values are related to the amount of substance present. Mass may be directly measured on the laboratory balance to 1/10 of a gram and estimated to 1/100 of a gram. Volume may be calculated for regularly shaped objects (cubes, right circular cylinders, etc.) by measuring the dimensions and subsequently performing calculations. For irregularly shaped objects, the volume may be determined by displacement of a liquid.


Density is an intensive property of a material. This value does not depend upon the amount of material present. Density can be calculated by dividing the mass of an object by its volume:


Density = Mass/Volume.


Exercise #1: List the least count and the precision to which one can estimate a measurement for the following instrument.


Least Count (units) Estimate to (units):

Ruler _______________ _______________

Vernier Caliper (cm scale) _______________ _______________

Micrometer _______________ _______________

Graduated Cylinder _______________ _______________

Balance _______________ _______________


Exercise #2: Measure the length of a metal rod to 1/100 cm using a ruler. Have four other people in the lab measure the same piece of rod and record the values in the table below.


Measurement Length of Rod

# x (cm)


1 _________

2 _________

3 _________

4 _________

5 _________

Average _________

Spread of Data _________

Calculate the average value of the length of the rod. Calculate the spread in the data by taking the difference between the highest value and the lowest value.


Using the vernier calipers, measure the length and diameter of the metal rod. Compare the length value of the metal rod obtained using the vernier caliper with the average value of the length found by using the ruler.


Length ____________ Diameter ___________


Method Length (cm)

Vernier Caliper (xvernier) __________

Ruler Average Value (xruler) __________


Calculate the % Difference between the two values using:





where xaverage is the average of xruler and xvernier.


% Difference _____________.


Calculate the volume of the metal rod (volume = r2l) using the length obtained with the vernier caliper.


Volume of metal rod_______________.


Exercise #3: Using the balance, find the mass of the metal rod and compute its density based upon the volume calculated in Exercise #2.


Mass of rod _____________

Computed volume of rod (from Exercise #2) _____________

Density using computed volume _____________.


From the density values provided to you by your instructor, identify the substance from which the metal rod is made. Calculate the % Error of the calculated density using





Identity of metal _____________

Density of metal (provided by instructor) _____________

% Error _____________.


Determine the volume of the rod by displacement of water in a graduated cylinder and compute its density. To accomplish this, fill a graduated cylinder with enough water to just cover the metal rod when it is placed in the graduated cylinder. Record the initial volume of water in the graduated cylinder before the metal rod is placed into the cylinder. Carefully place the metal rod into the graduated cylinder without splashing any of the water out of the cylinder. Record the final water volume. Calculate the volume occupied by the metal rod by taking the difference between the final volume reading and the initial volume reading. Calculate the density of the rod by dividing the mass of the metal rod by the volume (determined by displacement of water). Calculate the % Error of the calculated density versus the value provided by your instructor.

Initial volume reading _____________

Final volume reading _____________

Volume of rod by displacement _____________

Density using displacement _____________

% Error _____________


Questions:


1. In Exercise #2, is the spread in the data an estimate of accuracy or precision?


2. In exercise #3, which of the densities is more accurate? Why?


References:


1. Physics 1 Lab Manual, J. Moore, 2002.


2. Experiments in Physics, 2nd Edition, Peter. J. Nolan and Raymond. E. Bigliani, Experiment 4, "Measurement of Length, Mass, and Time", Wm. C. Brown Publishers, (1995).


3. Quantitative Chemical Analysis, 6th Edition, Daniel. C. Harris, Chapter 3, W. H. Freeman and Company, (2003).
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