Formal Lab Report Directions

Formal Lab Report Directions: NEVER USE "I" or "We" in a lab report

1. TITLE: A title that describes the lab. Center the title. Underneath the title, write “By Your Name(s) It should not be witty, like a newspaper. It should incorporate your Independent and Dependent Variables. For example: The Effects of Temperature on the Hatching Time of Chick Embryos. Each important word in the title should be capitalized.

2. INTRODUCTION: One to two paragraphs describing any background information pertinent to the lab. Any topics explored in the experiment should be addressed. This section includes a specific statement of the question or problem under investigation, and statements about other goals of the laboratory exercise. When applicable, do a literature search on the topic. Be certain to cite your sources. If you don’t cite your sources, you have PLAGIARIZED. Clearly state the purpose at the end of the section. (Let's say you were doing an experiment on pulse rate in different conditions, you'd discuss the answers to the following questions in your intro: Why do we have a pulse? What is pulse rate? What is a normal resting pulse rate? What are you investigating in this lab? Etc.)

3. HYPOTHESIS: The hypothesis section consists of a statement predicting the outcome of the experiment based on that hypothesis. Use the “if…then….”format.

For example: Hypothesis: If the temperature of a balloon is increased, then the volume of the balloon will be increased.

4. MATERIALS: This section consists of a list of materials, including the quantity of each one, required to carry out the experiment. An experiment designed by a teacher will include a list of materials needed, which was developed ahead of time. If it is helpful, a diagram showing experimental apparatus can be shown.

5. PROCEDURE: Written in a NUMBERED LIST. The procedure section describes each step in the experiment in enough detail so that a stranger can read it and perform the experiment. In a predesigned laboratory experiment the procedure is already written and the student only needs to rewrite the procedure in their own words. Make the rewritten procedure short and concise, but make sure it demonstrates an understanding of the experiment. In a lab designed by the student, the procedure should be a complete step-by-step description of how to carry out the experiment. Be Specific! Write it so that a stranger could repeat the experiment exactly just by reading your procedure

6. DATA/Results: Data is usually presented in a Data Table and include the following: TITLE - The data table should have a descriptive title i.e.) Table 1: the efficiency of plants at converting solar energy into chemical energy COLUMN -The data should be aligned correctly in columns with lines separating. HEADINGS - Each column must have a heading, which describes the type of data found in the column. UNITS - Each column heading must include the units of the data in that column.

GRAPHS: All graphs should include a TITLE that describes the data being plotted and AXIS LABELS that include the units of the data being plotted. Some graphs will have a curve (or line) fit to the data. In cases such as this one include the formula and parameters for the curve. You must make graphs with your data if you have taken quantitative data throughout your lab. I expect graphs to made by the computer. If you do not know how, then ask me.

CALCULATIONS (if you have any calculations): All calculations must be neatly presented with a subheading that describes the purpose of the calculation. Show the algebraic form of the equations (with VARIABLES), show the data substituted into the equation (include units) and show one sample calculation for each equation.

7. ANALYSIS: The critical analysis section is the place to interpret and evaluate your data and to speculate on other possibilities.

The following questions should be answered in your analysis:

A. What question/problem were you trying to answer? How did your experiment test this questions/problem?

B. What effect did your independent variable have on your dependent variable? (Ex: How did temperature affect the rate at which fish breathe?) Explain by comparing your experimental group(s) to your control group(s).

C. What does your data show? Discuss any trends that you see. (Ex: Seeds given different fertilizer sprouted 4 days before seed that were not given fertilizer. Additionally, the seeds that were given fertilizer grew and average of 4cm more over 14 days of the experiment than the seeds without it. REFER TO YOUR DATA/GRAPH

CONCLUSION: The conclusion should answer the questions posed in the purpose section of the laboratory and should also indicate whether the hypothesis is supported by the results. If the results do not support the hypothesis the possible reasons for the discrepancy should be noted and discussed (aka: sources of error). Discussion of the results should include new questions that the results have brought up. If applicable, the discussion should also consider any possible changes needed in the design of the experiment. Refer directly to your results! Literally use data from your table and graphs to support your conclusion. For example, “As seen in Graph 1, the trend in using roller-skates to commute to school has decreased by 87% in the past four years.”

A. Do your results support your hypothesis? Explain.

B. Identify possible sources of error in your experiment, including how these sources of error might have affected you results. How could you improve or change your experiment if you were to do it again?

WORKS CITED: List any sources you may have used to get information (perhaps for the introduction). Textbook? Credible website?

BELOW, THERE IS A VERY SIMPLE EXAMPLE OF A LAB REPORT TO GIVE YOU SOME GUIDANCE. The Effect of Pressure on The Boiling Point of Water By John Smith

Introduction:

Kinetic theory states that all molecules in matter are in constant motion (Kane and Sternheim, 1984). As these molecules absorb more energy they have a higher amount of random movement. As energy is absorbed in the form of heat the average kinetic energy (temperature) of the molecules will increase except during a phase change. The absorbed energy used in the phase change breaks the attractive forces between the molecules, thus transformation occurs in the orientation of the molecules. An example of a phase change would be the boiling point of water which is a change from a liquid to a gas. This can be observed by using a temperature versus time line graph when the slope becomes zero (plateau) The boiling point of water is expected to be 100.00 oC (Merck, 1976). The purpose of this experiment is to determine the effect that pressure has on the boiling point of water.

Hypothesis: If the atmospheric pressure is decreased, the boiling point of water will decrease,

Materials List: 500 ml beaker distilled water, thermometer, hot plate, Nalgene Brand Vacuum Chamber Word Processing Software

Procedure: 1. The required materials were selected and taken to the workstation. 2. The beaker was filled with 300 ml of distilled water. 3. The beaker was gently placed on the hot plate. 4. The thermometer was placed in the beaker and the initial temperature was recorded. 5. The hotplate was switched on to high. 6. The temperature was recorded every 2 minutes until 6 minutes after boiling began. 7. The hotplate was turned off and the materials were allowed to cool for at least 10 minutes before the equipment was dismantled. 8. Steps 1-7 were repeated inside the vacuum chamber Figure 1. The equipment for this experiment was set up as shown in this figure. (You may show pictures of your set up.)

Control Group - Normal Atmospheric Pressure

Control Group -Normal Atmospheric Pressure

Nalgene Vacuum Chamber Experimental Group - Inside Vacuum Chamber

Data / Results:

Table 1 Temperature at Which Water Boils Under Two Different Pressures Pressure (in Atmospheres) 1 atm 0.5 atm (Vacuum Chamber) Boiling Point of Water (C) 99.5 C 78.5 C

Boiling Point of Water Under Two Different Pressures

Control Group (1 atm) Experimental Group (0.5 atm)

Figure 2. A line graph of temperature versus time of the data obtained in Table 1

Calculations: Show/describe your worked out calculations if you have any. Analysis: Written in paragraph form. Don't try to write as if it is a literary novel. Pretend you are a robot.

The purpose of the experiment was to determine the effect of pressure on the temperature at which water boils. To do so, water was heated over time to a point at which it boils under two different pressures. The control group was tested under normal atmospheric pressure, and the experimental group was tested under lower pressure, using a vacuum chamber. As expected, lower pressures decreased the temperature at which water boils. A lower pressure exerts less force on the atoms of liquid water, allowing them to more easily vaporize. As illustrated in the graph above, the temperature at which water boils under normal pressure (1 atm) was 99.5 C, very close to the expected 100 C. It was observed that water boils at 78.5 C under 0.5 atm of pressure; a significantly lower temperature than the control group. IF YOU HAD MORE DATA, YOU COULD ELABORATE ABOUT ANY OTHER TRENDS YOU OBSERVED.

Conclusion: SHORT - A FEW SENTENCES ABOUT HYPOTHESIS/ IMPROVEMENTS/ SOURCES OF ERROR The hypothesis was supported by the results of this experiment because the boiling point did decrease as the pressure decreased.It was determined from the data plotted in the temperature versus time graph (Figure 2) that the boiling point of water is 99.51 oC. The hypothesis. The percent error was found to be 0.49%. Possible sources of error could have involved impurities in the water and human error in reading the thermometer. Possible sources of error may be impurities in the water which may be chemicals from dirty glassware. Improvements would include more accurate thermometers, clean equipment and proper reading of the thermometer. Further experiments could include more experimental groups to show a variety of pressures and boiling points.

Works Cited: Kane, Joseph W. and Morton M. Sternheim. Physics. New York: John Wiley & Sons, 1984 ed. Merck, Josef. Merck Index of Chemical Constants. New York: Benjamin/Cummings Publishing Company Inc. 1976.