Lab Report & Rubric Exercise

Title Title is descriptive and appropriate for the study conducted Interpret and analyze scientific information (11pts ) Introduction Includes a statement of the problem under investigation 1. Includes an explanation of why the experiment is being conducted 1.Refers to scientific information used in developing purpose and includes all background information relevant to the experiment For Hypothesis Driven Labs 2. Develop hypotheses based on the observation of natural phenomena (12 pts) 2. Links the background information to the hypothesis and predictions made. 2. Hypothesis is a formal statement based on natural phenomena. 2. Hypothesis includes the relationship between independent and dependent variable Use this section of the Rubric to asses the following lab report section.

Purpose- The main purpose for the lab was being able to generate a standard curve of bromcresol green with absorbance. Background/Introduction- By generating a standard curve this gives the ability to find points that are not on a graph. Many scientists such as chemists and biologists use this method for their data. This is used because it helps them determine the concentration of a solution. Standard curves are used for analysis in a lab. The spectrophotometer is used to measure the amount of light absorbed through the solution. On the graph recorded below, there is the independent and dependent variables. The independent variable is the concentration. This is the independent variable because we are in control of how much concentration is put into the test tube/solution. The dependent variable is the absorbance. This is because we are unable to control the amount of absorbance will occur in each test tube/solution. Therefore as the concentration increases, then the absorbance increases as well. This is because when there is more bromcresol green added to the water, therefore there are more molecules that are able to absorb the light.

3. Explain experimental design and procedure. Methods and Materials 3. Describe the data collection. Procedure for the experiment is outlined in steps such that others could repeat and described in complete sentences (no lists). Include example calculations if part of lab For hypothesis driven labs this is based on a testable hypothesis as a result of observation and prediction. The student should be able to: 3. Identify experimental constants 3. Identify necessary control treatment(s) 3. Identify the independent variable including levels of treatment 3. Identify the dependent variable

Procedure- 1) Label the test tubes as 1/10, 2/10, 3/10, 4/10, and 5/10. 2) Get two clean 10 ml Mohr pipets and bulbs. One is used for pipetting the standard solution and the other is used for water. 3) Now obtain 1.00x10^-4 M of bromcresol green standard solution. 4) Look at the SOP for Graduated Pipets, and follow the instructions. 5) Pipet 1 ml of the bromcresol green standard solution in the 1/10 test tube, 2 ml in the 2/10 test tube, 3 ml in the 3/10 test tube, 4 ml in the 4/10 test tube, and 5 ml in the 5/10 test tube. 5) Using a clear Mohr pipet and complete dilutions by adding 9 ml of water into the 1/10 test tube, 8ml of water in the 2/10 test tube, 7 ml in the 3/10 test tube, 6 ml in the 4/10 test tube and 5 ml in the 5/10 test tube. 6) Mix the dilutions using the vortex mixer. 7) Using the SOP on the spectrophotometer, turn on the spectrophotometer and let the lamp heat up. 8) Setting the mode of the spectrophotometer to absorbance and to 620 nm wavelength. 9) Using excel, calculate a graph of the data recorded.

Results/Data Collection 4. Record and organize data resulting from quantitative measurement using tables and graphs (32 pts) 4. Major findings are presented in logical order. 4. Tables and figures (graphs) are identified within the context of the results and integrated into the report and numbered consecutively Tables (points available will be multiplied by the number of tables necessary to communicate the type of data collected) Table title is above the table with caption (should include independent and dependent variables) Column headings indicate what is measured Column headings indicate units of measurement Independent variable is in increasing order in left hand column

Tube Initial Conc. Initial VolumeFinal Conc. Final VolumeAbsorbance x10^-4 m1.0 ml 1.0x10^-5 m 10.0 ml x10^-4 m2.0 ml 2.0x10^-5 m 10.0 ml x10^-4 m3.0 ml 3.0x10^-5 m 10.0 ml x10^-4 m4.0 ml 4.0x10^-5 m 10.0 ml x10^-4 m5.0 ml 5.0x10^-5 m 10.0 ml Data: Table 1 Final Concentration Calculations- (Concentration 1)(Volume 1) = (X)(Volume 2)

Results/Data Collection 4. Figures (points available will be multiplied by the number of figures necessary to communicate the type of data collected) A brief statement of figure explanation is below the graph. Title includes independent and dependent variable Independent variable is on horizontal axis and labeled including units of measurement Dependent variable is on vertical axis and labeled including units of measurement Legend indicates meaning ( if more than one line in a line graph or bar in a bar graph) The appropriate graph(s) were constructed. An appropriate statistical test was selected. The statistical test was used correctly for presentation of findings

5. Interpret and analyze data and come to conclusions based on the evidence presented (28pts) Discussion/Conclusion 5. Describes the relationship between the independent and dependent variable based on experimental results. 5. Explains patterns, trends, or lack of trends in the data For Hypothesis Driven Labs 5. Link hypothesis to experimental results using evidence presented. 5. A statement about whether the hypothesis was supported or disproved is written based on experimental results. 5. Explains how major findings support or refute hypothesis. Discuss the data to support your claim. 5. Summarizes the major findings 5. Explains how the experiment might be revised to increase its reliability 5. Suggests a potential question for further research

Discussion- By using the techniques of pipetting, we are able to make a series of dilutions. We are also able to generate a standard curve. Before pipetting, the calculation of finding the final concentration took place. By using the spectrophotometer, it allows the ability to measure the amount of light being absorbed by the dilution. Then pipetting an increasing amount into each test tube and mixed them together using the vortex mixer. According to the table and graph, the data was accurate and supported the hypothesis. As the concentration level increased, so did the absorbance. This is because there was more molecules able to absorb the light through the bromcresol green. The correlation was According to the table, the absorbency of each test tube increased each time. Because of the increase in the table, the graph showed increase in data as well. The line of best fit lined up almost exactly with the data points. Since we are able to generate a standard curve, this gives the ability to be able to find points that are not on the graph by plugging in a number for X into the equation. Conclusion- My data supports my hypothesis.

References APA or ACS format is used throughout the text and in the reference section Presentation The report is well organized, clearly written, and easy to follow. Appropriate vocabulary is used. Few spelling or grammar errors