"STICK TO IT!"
Properties of Pressure Sensitive Adhesive Tapes

Developers:

Fred C. Vincent
Lincoln High School

Dr. Enrique Michelotti
Agriculture Exploratory Research
Rohm and Haas Company

Dr. Allen Marks
Construction Products
Rohm and Haas Company

Dr. Brad Jacobs
Adhesives
Rohm and Haas Company

Special thanks to Nancy Goth for computer graphs and diagrams and Richard Cummings for advice on statistics.

Topic Area:

Experimental process, adhesion/cohesion, statistical analysis.

Grade 
Levels:

High School

Disciplines:

High school physical sciences (physics and chemistry). Some activities can be adapted for lower grade levels.

Goals:

By using the experimental process (the way scientists go about solving problems) and working as research teams:

1. Compare different types of pressure sensitive adhesive tapes.
2. Develop and carry out tests for variables affecting the force needed to
3. peel tape off a surface.
4. Quantitatively compare the time needed for a force to peel various
5. tapes from different surfaces.
6. By taking a specific tape on a specific surface, statistically analyze the
7. time needed to peel the tape with different peel forces.

Introduction:

Various tapes and adhesives are often encountered in our everyday lives, but rarely do we give them much serious thought. This series of labs is based on pressure sensitive adhesive tapes, which are inexpensive and easy to obtain. All the equipment in this series of experiments is readily available at moderate prices. These experiments seem at first rather simple, but students and teachers will quickly see how many variables are involved in measuring and comparing the various physical properties of adhesive tapes. They provide a source of experiments that are safe and a model of how research is performed.

Pressure sensitive adhesive tapes consist of two components: backing and adhesive. The backing is the most important component with the adhesive securing the bonding to another surface to serve some useful function. Most adhesives are made with weak adhesive bonds so that they can easily be removed; however, there are cases where tape is not meant to be removed and a permanent bond is preferred. Modern chemistry can produce adhesives with various desired properties.

These experiments can be used in a variety of ways; as a group, they can form a unit of activities or spread over a period of time. Each can also be performed as an individual experiment.

These experiments can be used in a variety of ways. They can illustrate the experimental process by having students work in research teams developing the experiments using their creativity and problem solving skills. The experiments can be used as an introduction or summary of bonding and/or organic chemistry.

History.

Tapes for medicine have been used for hundreds of years and a U. S. patent for rubber based adhesive tape, to be used in hospitals, was issued in 1845. In 1899 natural rubber based zinc oxide was developed that was similar to today's hospital tapes. Industrial tapes first appeared in the 1920's and transparent cellophane tape was introduced in the late twenties. During the Second World War the lack of rubber led to the development of polymer based adhesives used so extensively today.

Adhesives range from such natural substances as starch and rubber to synthetic compounds that are classified as water based, solvent based, and hot melts. There are estimated to be between 200 and 400 different types of tapes with thousands of uses.

Research Teams: Cooperative Groups using the Experimental Process.

The experiments are described in a form that allow the maximum input by the students; directions are deliberately vague to foster student creativity and problem solving skills. Teams, working in groups of four, will allow students to check each others' work and share responsibilities. The research team will analyze the experiment, develop an experimental design on how to do the lab, perform the experiment, exhibit data, draw conclusions, and produce a written report.

Pivotal to the success of student directed lab experiments is the role of the teacher. The teacher is a facilitator seeing that each team is functioning to its full potential. Instead of a detailed procedure in which each student is doing the same things, teams may each be doing something different. This at first may put a great strain on the teacher and may seem chaotic; however, students, working in teams, learn to be independent in directing their own experiments. The reward for a teacher is to see students enthusiastically working as a team, designing their own experiment, and using their creativity.

These experiments illustrate real world situations where there are many variables often influencing one other. This contrasts to the traditional science experiment where nice perfect results are expected. Traditional labs have their place and they often show a concept not tangled in many possibilities, but they usually don't reflect real world situations. Students need a mixture of both these types of laboratory experiences.

The experiments are presented in increasing levels of difficulty. The first could be done with a middle school class while the fourth would best be left for upper level high school students with good backgrounds in mathematics. Teachers should perform all of these experiments beforehand to familiarize themselves with problem areas when students perform the experiments. This is vitally important as directions are deliberately kept short to allow the research teams to think through and develop their own procedures.

Student understanding of the experimental process may vary greatly. If the process is taught each year, starting from the early grades, they will have a comprehensive knowledge at the high school level and little instruction will be needed. Unfortunately in today's schools this is rarely the case.

Experimental Process:

The following is a general outline on how to solve a problem by the experimental process.

1. Problem or goal. States what needs to be solved.
2. Hypothesis. An educated guess at solving the problem. A hypothesis is optional.
3. Experimental design. Includes the testing procedures and apparatus needed to perform the experiment. Must be agreed upon by all members of the team and explained to and approved by the teacher before beginning.
4. Performing the experiment. Set up the apparatus and carry out the experiment according to the experimental design.
5. Collecting data. Record and label all measurements.
6. Displaying data. Data can be displayed in the form of charts and graphs.
7. Analyzing data. Concluding statements often describing numerical patterns are used to answer the original problem and predict futureevents. Determine if the hypothesis is correct.

Materials:

Tapes. Any kind of tape can be used, but the following have the same 2.5 cm thickness, were easy to work with, and produced different results.

A. Tuck Masking Tape		C. 3 M Elastic Tape
B. 3 M Strapping Tape		D. 3 M Painter's Masking Tape

Kits:

See apparatus diagram.

Stand Cardboard. 9" x 12." Used to support the surfaces being tested.

Surfaces 2.0"x6.0." They slide into the cardboard stand.

1. Wood		3. Aluminum
2. Glass		4. Plastic

Weights Lead sinkers. This combination will allow forces from 1 oz to 10 oz to peel tapes off surfaces. Regular hooked or slotted weights can also be used.
1.0 oz (2)
1.5 oz (2)
2.5 oz (2)

Ruler 12" transparent.

Scissors A sharp pair for cutting tape.

Paper clips 2" steel. Used as weight holders.

Microscope slide Placed on tape to even pressure on the surface.

Heavy weight 1000g. Place on microscope slide to provide uniform pressure.

Glossary:

Adhesion (pressure sensitive) - The bond produced by the contact between a pressure-sensitive adhesive and a surface.

Adhesive - Any material which will usually hold two or more objects together solely by intimate surface contact.

Adhesive failure - Occurs when the tape is pulled off the surface and adhesive remains on the surface.

Backing - A relatively thin flexible material to which the adhesive is applied.

Cohesion (cohesive strength, internal bond) - The ability of the adhesive to resist splitting. Good cohesion is necessary for clean removal.

Dwell time - Length of time a pressure is exerted on a tape placed on a surface.

Filaments - Thin elongated "threads" of glass, polyester, nylon, or other high strength materials.

Peel Force - Force needed to peel a tape from a surface.

Pressure - Force that is applied to tape on a surface.

Pressure Sensitive - A term commonly used to designate a distinct category of adhesive tapes and adhesives which in dry form are aggressively and permanently tacky at room temperature and firmly adhere to a variety of dissimilar surfaces upon mere contact without the need of more than finger or hand pressure. They require no activation by water, solvent, or heat in order to exert a strong adhesive holding force toward such materials as paper, plastic, glass, wood, cement, and metals. They have a sufficiently cohesive holding and elastic nature so that, dispite their aggressive tackiness, they can be handled with the fingers and removed from smooth surfaces without leaving a residue.

Sheer adhesion - The ability of a tape to resist the static forces applied in the same plane as the backing.

Surface failure - Occurs when the surface (such as cardboard) pulls off onto the adhesive tape.

Tacky - The condition of a adhesive when it feels sticky or highly adhesive. Sometimes used to express the idea of pressure sensitive.

Van Der Waal forces - Force of attraction between molecules.

Engagement Activities:

These demonstrations will engage students by exciting their curiosity and interest. This can lead to a discussion on how adhesives are part of our every day world and what holds things together.

1. Demonstrations of types of adhesion.
2. Magnets on iron. Magnets are attracted to iron by magnetic attraction.
3. Rubber balloon on a wall. A rubbed balloon will stick to a wall by electrostatic attraction.
4. Velcro. Velcro surfaces sticks together by mechanical means, where the fibers are intertwined with one another.
5. Suction cups. Held to surfaces by air pressure.
6. Adhesive tapes Pressure sensitive adhesive tapes are mostly bound to a surface by molecular attraction due to Van Der Waal forces. The strength of the adhesion depends on the chemical nature of the adhesive and the surface.

Display. Show examples of pressure sensitive adhesive tapes such as labels, duct tape, packaging tape, masking tape, cellophane tape, postit notes, elastic tape, and insulation tape.

Experiment 1.

Comparison of Adhesive Tapes.

After gaining some familiarity with types of adhesives from the engagement activities, students will direct their own investigations of the physical properties of pressure sensitive adhesive tapes. The four tapes listed in materials have been found to give good results. Distribute tapes as tape A, B, C, and D, without allowing the students to see the brand name. Other tapes can be used, but be sure they are tested beforehand, so any possible problem areas are known.

The students will first be asked to develop an individual list of physical properties of adhesive tapes. The team through discussion will develop a team list which can be placed on the blackboard or large paper for class viewing. The teacher will lead a discussion analyzing all the teams' lists and developing a class list.

The role of the teacher is to observe the cooperative groups and ensure that all members are actively involved. When teams develop their charts, comparing the physical properties of the four tapes, emphasis must be placed on all members of the team doing the tests, giving input, and analyzing the results.

Student Directions. Goals: Develop a list of physical properties for evaluating adhesive tapes. Develop a chart comparing the different tapes with their properties. Match the properties of the tape with the brand name. General Procedure. a. By Brainstorming individually and then in a team, develop a list of physical properties of adhesive tapes. b. By examining the team lists, develop a class list. c. As a team, develop a comparison chart of four tapes and their physical properties. d. Develop ways for comparing the tapes and fill-in the chart. The charts can be displayed, compared, and discussed by the class. e. Match the letter of the tape with its name and suggested use. Painter's masking tape. Strapping tape. Regular masking tape. Label tape. f. Each team submits a written report including the individual physical properties list, the team list, the class list, the comparison chart, description of how each property was tested, and the identification of each lettered tape.

Post-Experiment Discussion:

Using team charts, displayed to the whole class, the teacher can lead a discussion analyzing the similarities and differences of the results. Discuss how and why results from different teams may vary.

Comparing the tapes can lead to a discussion on qualitative (relative) and quantitative (measured) comparisons. Encourage students to develop ideas as to how they could quantify the testing of each property.

Comments:

See Sample Results Experiment 1.

The following is a list of the most likely physical properties listed by the teams. Teams may use different terminology in naming the property which can lead to a discussion on the need for and a use of a common vocabulary. Teams may come up with properties not listed here and the class, with the guidance of the teacher, can decide whether some can be eliminated from testing.

Tackiness. A relative (qualitative) judgment can be made by using a finger touching the adhesive side of the tapes.
Quantitative measurement can be made by allowing a metal ball or weight to roll down a ramp onto a length of tape with the adhesive side up and taped at the ends. The length the weight rolls along the tape provides a quantitative measurement for tackiness. The greater the distance the weight rolls the less the tackiness. This is a standard industrial research method used for testing adhesive tapes still used today.
* See "Teaching The Scientific Method Using Adhesives" by Ileen Green in the Project L*A*B*S 1990 Part 2 Book.

Strength How does the tape resist tear? Tapes can be compared by tearing each and ranking their relative strengths.

Elasticity Can the tapes be stretched? Compare the tapes by pulling on them to see if they will stretch without tearing.

Thickness Relative visual judgments can be made. Results can be quantified by measuring the thickness using a micrometer or vernier caliper.

Peel force Qualitative judgment can be made my applying tape to a surface and estimating the relative force needed to peel it off a surface.
Quantitative measurements of peel force will be done in Experiments 2, 3, and 4.

Adhesive failure Place the tape on a surface. Pull off and estimate the relative amount of adhesive left on the surface.

Surface Failure Place tapes on cardboard and pull off. Estimate the relative amount of cardboard left on the tape.

Experiment 2.

Variables in Peeling Tape From a Surface.

This experiment looks at variables affecting the force and time needed to peel a tape from a surface. Teams are to come up with a list of possible variables and combine them into a class list. Teams may choose their own variables to be tested or the teacher may assign specific variables (such as those mentioned in the Comment's Variables List).

Each team will discuss and design an experiment to test for each variable using the experimental process. Team members can divide up the work but each member has a responsibility for understanding the whole experiment.

The teacher's role is to help each group develop an experimental design which is reasonable, uses the materials in the kit, will change only one variable at a time, and produce results that are easily interpreted.

Student Directions. Goals: Develop a list of variables that affect the force and time needed to peel a tape from a surface. Develop means of testing five of these variables. Test and draw conclusions as to how the variables affect the force and time neededto peel a tape from a surface. General Procedure. a. By brainstorm individually and then as a team list the variables involved in measuring the force and time needed to peel a tape from a surface. b. From the team lists develop a class list. c. Each team will develop an experimental design explaining how each of five selected variables will be tested. For each of the variables measure the amount of time it takes to peel the tape from a surface with a given force. Be sure that one variable at a time is tested, everything else must remain constant. The experimental design must be approved by the instructor before actually beginning the experiment. d. Collect data and give a concluding statement for each variable. e. Submit a team report including the list of variables, the experimental design, diagram of apparatus, the data chart, and concluding statements.

Post-Experiment Discussion:

By reading the team reports, the teacher can analyze how the experiment was performed, the meaningfulness of the data, and if the conclusions are reasonable. From this analysis the teacher can give feedback to each team. Discuss how repeating the experiment and increasing the number of trials can affect the accuracy of the results.

An interesting extension would have a group of students develop a class report from combining the teams' results.

Comments:

These experiments will use the kits to set up the apparatus shown in the diagrams. The length of tape placed on a surface, can be pressed with a weight placed on a microscope slide, which is on the tape and the surface (see Apparatus Diagram). Care must be given when placing the tape on the paper clip and placing weights on the paper clip as not to pull the tape. Be careful when timing the start of the peel force to gently allow the weights to hang. The sudden dropping of the weights can cause the tape to prematurely rip away.

Peel force and time to peel can both be measured. The problem with measuring peel force is that too light a force produces no peel while too heavy a force produces almost instant peel. There is, however, a wide range of forces which produces peel at various rates of time. Because of this many of these tests use a constant peel force and the time to peel is measured. Teachers need to do the experiments beforehand and note appropriate peel forces to advise students. Otherwise teams may be needlessly taking a long time finding appropriate forces to test.

Variables List

The following are variables effecting the force and time needed to pull a tape off a surface;

Variables most likely to be tested. See Sample Results Experiment 2.

1. Pressure on tape. Provide light pressure on one tape and heavy pressure on the other.
2. Dwell time. Test one tape immediately and allow the other to stand with the pressure on it for some time before testing.
3. Length of tape.(area) Test two tapes of different lengths.
4. Nature of surface. Test different surfaces found in the kit.
5. Angle of peel force. Test at three different angles.
6. Reuse of tape. Test a tape and test the same tape again.
7. Time adhesive side is exposed to air. Allow tape to stand with the adhesive side exposed to air for a few hours.
8. Water resistance. Allow tapes on surfaces to remain under water for period of time.

Variables least likely to be tested Must remain constant

1. Heat
2. Humidity
3. Width of tape
4. The swing of the force attached to the paper clip.

Experiment 3

Quantitative Testing of Tapes
on Surfaces

Quantitative testing is done on four different surfaces with four different types of tape. The teams must be careful that the variables found in Experiment 2 remain constant with only the type of tape varying for each surface. The teacher, having previously done the experiment, may suggest a peel force for each surface. Teams measure the time to peel for each of the tapes on four surfaces.

Student Directions. Goals: Compare the time to peel tape from a surface with a given force for four different tapes on four different surfaces. Collect, display, and interpret the results of the experiment General Procedure. a. Each team submits an experimental design to be approved by the teacher. Explain how, with a given peel force, the time needed to peel each of the four tapes from a given surface will be measured. Repeat testing the tapes on the other three surfaces. b. Each team will develop a chart and bar graph showing their results c. Teams will display their results to the class for comparisons. d. Report will be submitted including the experimental design, apparatus diagram, data charts and graphs, and a conclusion.

Post-Experiment Discussion:

When team charts are compared there probably will be differences in the results. Use this as a way of describing how research is done is laboratories where tests are done numerous times and statistics becomes very important. It often upsets students to know that there is no definitive "right number."

Class results can be gotten by combining the teams' results. Peel time data can be averaged from the trials. Be sure that when developing class results, such as averages, the math is done by a number of students to insure accuracy. Each team can develop a chart and bar graph showing the class results. Discuss why the class results are considered better than the the team results.

Comments:

See Sample Results and graphs, Experiment 3.

Care must be taken in using an appropriate peel force for a surface. In this experiment the strapping tape was very strong and it was simply recorded that it hadn't peeled after a period of time. If a stronger force was applied the strapping tape would peel faster , but the other tapes may peel in a split second and thereby would not give meaningful comparative results.

Experiment 4

Statistical Analysis of Adhesive Tape Data.

This experiment takes some rather simple data and shows how it can be analyzed statistically in great depth. It illustrates for students the importance of mathematics in scientific research .

Take one tape on one surface and by varying the force measure the time to peel. Each member of the team can perform the experiment and the results combined. A few teams could combine results to provide a larger number of trials.

Actual time to perform the experiment is short; the major portion of time is needed for the statistical analysis of the data.

Student Directions. Goals: Determine how the time to peel a tape (peel time) is effected by the peel force. Statistically analyze the data by combining the results of repeated trials. Procedure. a. Have teams select one tape on one surface. Vary the peel force in intervals of 0.5 oz. and measure the peel time. b. Combine results with others who did the same experiment. c. Develop a chart showing the peel force and peel time for each trial and the average time. d. Graph the following relationships: For each trial the peel force with the peel time. The peel force with the average peel time. A box plot of the peel force with the peel time. e. Advanced statistics. Optional based on the mathematics background of the students. Calculate the mean, median, and mode for each weight.. Calculate the standard deviations for each weight. Develop, computer generated graphs, of peel force with the peel time presented in various forms (squared, square root, reciprical, etc.). Try to find a relationship that is linear. f. Turn in a report containing all data, charts, graphs, and conclusions.

Post-Experiment Discussion:

Science teachers can collabotate tthe statistical analysis with math teachers. The graphs with various manipulations of peel time (squared, square root, reciprical) can be analyzes. Students should be able to state the relationship of variables in words (e.g. as the peel force increases, the time to peel decreases).

Students can try to find a linear direct proportion relationship by viewing the graphs. This would be a straight line moving away from the origin with the variables both increasing.

Comments:

See Sample Results and Graphs. Experiment 4.

The teacher must make sure all students are analyzing the data and understand the statistical analysis as there is a tendency for the math oriented student to take on most of the responsability.

Students can first do the mathematics and simpler graphs by hand with the aide of a calculator. Students can then use a computer spreadsheet and graphics program to check their mmathematics and produce the more sophisticated graphs.

The Experiment 4 Sample Graphs are computer generated with the average time. The lower right graph is a box graph with the range of peel times indicated.

Alternative Presentation of Experiment 4

1. Select a relatively small and large peel force to measure the peel time.
2. Place these two points on a graph.
3. Predict the peel times for intervening peel forces.
4. Experimentally measure the peel time for the predicted peel forces.
5. Compare the predicted values with the measured values. Analyze by calculating the absolute and relative errors.
6. Manipulate time values to see if a linear (straight line) relationship between the peel force and peel time can be found.

Extensions:

There are limitless possibilities for experimentation using different adhesive tapes on various surfaces, and numerous variables. Teams can develop their own experiments and individuals their own science fair projects. The following are some ideas for expanding on the series of experiments just presented.

1. Test specific types of tape such as; fabric tapes, paper tapes, cellophane tapes, metal foil tapes, reinforcement tapes, double sided tapes, band-aides, electrical tapes, and labels.
2. Test different types of surfaces such as; metals, plastics, woods, and fabrics..
3. Any of the variables listed in Experiment 2 can be statistically analyzed as in Experiment 4.
4. Test chemical properties. such as; flame test, acid test, base test, and effects of various solvents. Caution! Since poisonous fumes could be produced, work must be done in a chemistry laboratory, under a hood, with the close supervision of a science teacher.

References:

Satas, Donatas, Handbook of Pressure Sensitive Adhesive Technology. Second Edition. Van Noorstrand Reinhold, New York, 1989.

Test Methods for Pressure Sensitive Tapes, 9th Edition. Pressure Sensitive Tape Council, 1989.

Experiment 1: Comparison of Adhesive Tapes.

Sample Results.

Property	A	B	C	D
Tackiness Finger test Ramp Test Quantitative	Medium 11.2 cm	Very Tacky 7.5 cm	Medium 15.5 cm	Medium 8.6 cm
Flexibility Pull test	None	None	Very Flexible	None
Strength Pull test	Weak	Very Strong	Strong	Weak
Thickness Visual Micrometer Quantitative	Thin .07 mm	Medium .19 mm	Thin .09 mm	Thin .08 mm
Peel Force Stick on test	Good	Very Good	Good	Good
Adhesive Fail Sticks to surface	None	None	None	None
Surface Fail Cardboard Sticks to tape	Little	A lot	Little	Little
Brand of Tape	Masking Tape Tuck	Strapping Tape 3M	Elastic Tape 3M	Painter's 3M Masking Tape

Experiment 2: Variables in Peeling Tape from a Surface.

Sample Results.

1. Pressure on tape.

Condition	Pressure	Peel Time
Tucks Masking on Glass	Light	0.5 sec.
Peel Force = 5.0 oz.	Heavy	65 sec.

Conclusion. The greater the pressure placed on a tape the greater will be the peel time.

2. Dwell time.

Condition	Dwell Time	Peel Time
Painter's Tape on Glass	1 min.	6 sec.
Peel Force = 100 g.	60 min.	23 sec.

Conclusion. The greater the dwell time of the pressure on the tape and surface, the longer the peel time.

3. Length of Tape.

Condition	Length	Peel Time
Tucks Masking on Wood	1.0 cm	20 sec.
Force = 2.5 oz.	2.0 cm 3.0 cm	48 sec. 143 sec.

Conclusion. The greater the length of tape the greater is the peel time.

4. Reuse of Tape.

Condition	Put on a Surface	Peel Time
Tucks Masking on Glass Peel Force = 5.0 oz.	1st time 2nd time	29 sec.   3 sec.
Elastic Tape on Glass Peel Force = 4.0 oz.	1st time 2nd time	310 sec.   4 sec.
Elastic Tape on Aluminum Peel Force = 4.0 oz.	1st time 2nd time	255 sec.  23 sec.

Conclusion. Reuse lowers the time and force needed to peel tape from a surface.

5. Angle of peel force.

Condition	Angle of Peel Force	Peel Time
Painter's Masking Tape on Glass	45	10 sec.
Peel Force = 2.5 oz.	90 120	15 sec. 110 sec.

Conclusion. The greater the angle of the peel force, the greater is the time needed to peel the tape.

6. Time adhesive side exposed to air.

Condition	Time Exposed	Peel Time
Tuck Masking Tape on Glass	5 min. 24 hours	45 sec. <200 mins.
Strapping Tape on Glass	5 min. 24 hours	65 sec.    15 sec.
Painter's Masking Tape on Glass	5 min. 24 hours	6 sec.    13 sec.
Elastic Tape on Glass	5 min. 24 hours	24 sec.     4 sec.

Conclusion. With the two masking tapes an increase in the time of exposure of the adhesive side to air causes the peel time to increase. The masking tape and adhesive tapes showed a decrease in peel time with an increase in the time of exposure of the adhesive side to air.

7. Water resistance.

Condition. On glass under water doe 2 hrs.	Peel Force	Peel Time
Tuck Masking Tape	3.0 oz	Falls off
Elastic Tape	3.0 oz	10 secs.
Painter's Masking Tape	3.0 oz	Falls off
Strapping Tape	3.0 oz	Falls off

Conclusion. Water penetrates into the adhesive and appears to have dissolves it. There is no adhesive remaining except for the elastic tape.

8. Nature of Surface.

Conditions	Type of Surface	Peel Time
Elastic Tape Peel Force = 5.0 oz.	Glass Plastic Aluminum Wood	60 sec. 15 sec. 11 sec. 34 sec.

Conclusion. Peel time varies greatly with the different types of surfaces.

Experiment 3: Time to Peel Tapes From Surfaces

Sample Results

Surface	Masking Tape Tuck	Strapping Tape 3M	Elastic Tape 3M	Painter's Masking 3M
Glass Force = 5 oz.	73 sec.	<300 sec.	60 sec.	8 sec.
Plastic Force = 7 oz.	95 sec.	<300 sec.	9 sec.	48 sec.
Aluminum Force = 5 oz.	125 sec.	<300 sec.	11 sec.	10 sec.
Wood Force = 5 oz.	110 sec.	<300 sec.	34 sec.	110 sec.

Bar graphs

Experiment 4: Statistical Analysis of Tuck Tape on Glass.

Sample Results of Peel Time in Seconds

Peel Force	Trial 1	Trial 2	Trial 3	Average
3.0 oz.	67	220	355	214.0
3.5 oz.	75	80	122	93.3
4.0 oz.	55	44	42	47
4.5 oz.	20	16	12.7	12.7
5.0 oz.	9	15	10.0	10.0