Experiment The Properties of Water
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The Properties of Water
Margaret E. Vorndam, M.S. Version 42-0129-00-01
Lab Report Assistant
This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.
Exercise 1: Surface Tension Results
D. State your hypothesis. What do you think will happen?
Data Table 1: Results of Surface Tension Trials
Trial # Paper Clip Weight, grams Does it Float? Yes/No
1
2
3
4
5 Compacted
6 + Detergent (optional)
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E. Record the results of your trials in the Data Table 1 above.
F. Did the weight of the paper clip affect whether it floated or not?
G. Did the size of the paper clip affect whether it floated or not?
H. Did the shape of the paper clip affect whether it floated or not?
I. Optional: Did the addition of detergent influence the flotation of the paper clip? Explain.
Questions
A. Why must the paper clips, tweezers, and bowl be clean?
B. If one paper clip did not float, what might be a reason?
C. Was your original hypothesis supported or refuted?
Discussion
A. Give two examples where the surface tension of water is important. Why is it important in these examples?
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Data Table 2: Results of Capillary Action Exercise
Capillary Tube Internal Diameter, mm Height of Liquid, cm
B. Would other liquids have the same surface tension property? Why or why not? How might you test this (for instance, the behavior of a paper clip and olive oil)?
C. Is there a limit to the tensile strength of the water surface? Explain.
D. What experimental variables are important to consider when doing this exercise?
E. What is the purpose of this exercise?
Exercise 2: Capillary Action Results
A. State your hypothesis. What do you think will happen?
B. Record the results of your exercise in the Data Table 2.
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C. Record the average results of at least three other students’ exercises in a table like Table 3. Why is it important to note how many data sets (N) are used in the average?
N (number of data sets averaged) =
Data Table 3: Results of Capillary Action Exercise
Capillary Tube Internal Diameter, mm
Height of Liquid, cm
D. Graph your data results from Tables 1 and 2 in a scatter graph, line graph, or bar graph similar to the graph layout in Figure 1. Also present the average results of the other students’ data using a second scatter, line or bar on the same graph so that the results of both your data and other students’ data can be compared. The graph should present two series of data, your results and the average students’ results, with Capillary Tube Internal Diameter on the x-axis, and height of liquid on the y-axis. Note: Do the graph by hand, or you may use a graphing program, and copy the resulting graph to your work area. Place your graph here:
E. What is the advantage of comparing your data to that of the other students’ data? Which set of data would you trust the most? Why?
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My data from Data Table 1 is recorded in (student to specify color of line) Other students’ average data from Table 2 are recorded in (student to specify color of line)
Questions
A. What did you observe at the end time of the exercise?
B. What caused the difference in the results that you obtained?
C. How did your outcome compare to that of the other students?
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D. Was there a linear relationship between Internal Diameter and the height of the water? What might explain this?
E. Was your original hypothesis supported or refuted?
Discussion
A. Give two examples where the capillary action of water is important. Why is it important?
B. Would other liquids have the same property? Why or why not? How might you test this?
C. Blood in our bodies travels through capillaries of differing internal diameters. This means that our heart can work less hard, since blood contains water as part of the fluid, and the capillary action of water in tubes helps to move the blood along.
1. Why does blood pressure rise as patients experience the progression of atherosclerotic disease?
Does this seem to be counter to what you have learned about capillary action? How do you explain the apparent discrepancy (note: see also c., below)?
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2. In plants, vascular system elements called xylem and phloem are lined up like long straws from the root of the plant to the leaves. The xylem of plants moves water and dissolved nutrients up to the leaves. Can you suggest what aids the movement of water up the plant, in addition to the capillary action of water?
3. Why is it harder to suck a beverage through a small diameter straw than through a large diameter straw?
4. What experimental variables are important to consider when doing this exercise? What could explain the difference in outcomes between your data and the data of other students?
5. What is the purpose of this exercise?
Exercise 3: Density Results
A. State your hypothesis. What do you think will happen?
B. Record what actually happened here:
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Questions
A. What did you observe in this exercise?
B. How does this outcome compare to what you observe about the action of ice (the solid form of water) on liquid water?
C. Was your original hypothesis supported or refuted?
Discussion
A. Why is it important that ice floats?
B. Give two examples where the property of water density is important.
C. Do all solids float on their liquid forms? Why or why not?
D. The density of liquid olive oil is about 0.92. What can you say about the likely density of solid oil? Why?
E. Will olive oil float or sink if it is added to liquid water? Why?
F. What experimental variables are important to consider when doing this exercise?
G. Attempt to find another pure substance, like water or oil, in which the solid form floats on the liquid form (Note: do not spend more than 5 minutes on this question!).
H. What did you learn from this exercise?
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Exercise 4: Specific Heat Capacity Results
A. State your hypothesis. What do you think will happen?
B. What difference do you observe in the heights of the frozen solid oil and water as compared to the liquid forms prior to freezing? What might explain this result?
C. Record what actually happened in a table similar to Tables 4 and 5.
Data Table 4: Results of Specific Heat Exercise for Water
Ambient (Room) Temperature in Which Exercise was Conducted, oC.
Time, minutes Liquid Collected, mL
All solid ice gone
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Data Table 5: Results of Specific Heat Exercise for Oil
Ambient (Room) Temperature in Which Exercise was Conducted, oC.
Time, minutes Liquid Collected, mL
All solid oil gone
D. Graph your data results from Data Tables 4 and 5. Use a scatter graph or progressive line graph, with time noted on the x-axis, and mL of liquid collected on the y-axis. You should have two scatter plots or lines on your graph (not two separate graphs) —one for water and one for oil. Note: you may use a graphing program, and copy the resulting graph to your work area. Place your graph here:
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E. Calculate the melting rate for each of water and oil. The melting rate is equal to the slope of each of the separate lines of your graph, one for water, and one for oil. The easiest way to calculate the slope for each is to use your graphing program, and ask it to determine the trendline for you, as follows:
F. Share your melting rate for water and the oil with other students, if possible. Make sure to also obtain the ambient (room) temperature from the other students. Why?
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Data Table 6: Comparison of Melting Rates for Specific Heat Exercise
Results Reported By
Water, mL/min
Oil, mL/min General Ambient Temperature, oC.
Student
Student A
Student B
Student C
Student D
Average =
Questions
A. Was your original hypothesis supported or refuted?
B. What do you observe concerning the plot line of the oil versus the plot line of the water? What does this mean?
C. How close is your melting rate to the melting rates reported by at least three other students for the water and for the oil?
D. Generally, what might you conclude about the amount of specific heat needed to melt 50 mL of water versus 50 mL of oil?
E. How could you explain the differences in your data observations as to when the water and oil began to melt?
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F. What experimental variables are important to consider when doing this exercise? What could explain the difference in outcomes between your data and the data of other students?
Discussion
A. How might you design a similar experiment to determine whether the specific heat (amount of heat required to raise 1 gram of a material by 1 ÂşC) of one substance is more or less than another substance? What variables must you consider in the design of your experiment? Give an example of such an experiment that compares the specific heats for two different substances.
B. An alternative energy-savvy person decides to use 55-gallon drums filled with liquid to warm her house at night in the winter. She has to make a decision about what liquid will be the most efficient at storing heat from sunlight that shines on the drums during the day. Should she use water or oil in the drums? Why?
Laboratory Summary
What have you learned from doing this laboratory?
