1. Scientific Method: Experimental Design and Laboratory Report Writing Available online @ http://www.redwood.org/stewart Available online @ http://www.redwood.org/stewart

2. Choose a topic Observe the world around you! Consider: Prior experience Initial testing RESEARCH Observe the world around you! Consider: Prior experience Initial testing RESEARCH EXAMPLE: After studying about recycling, members of John ’ s biology class investigated the effect of various recycled products on plant growth. John ’ s lab group compared the effect of different aged grass compost on bean plants. Because decomposition is necessary for release of nutrients, the group hypothesized that older grass compost would produce taller bean plants. Three flats of bean plants (25 plants/flat) were grown for 5 days. The plants were then fertilized as follows: (a) Flat A: 450 g of 3-month-old compost, (b) Flat B: 450 g of 6-month-old compost, and (c) Flat C: 0 g compost. The plants received the same amount of sunlight and water each day. At the end of 30 days the group recorded the height of the plants (cm), and plant health was described. Choose topicExperimental OrganizerDataLaboratory Report

3. Experimental Organizer  To get you started, organize your ideas into an Experimental Organizer. Eventually, you will use this to write your complete Laboratory Report. Choose topicExperimental OrganizerDataLaboratory Report

4. Title  The effect of IV on DV. EXAMPLE: The Effect of Different Aged Compost on Bean Plant Growth. Choose topicExperimental OrganizerDataLaboratory Report

5. Hypothesis  If IV then DV.  Be specific.  If IV then DV.  Be specific. EXAMPLE: If older compost is applied, then plant height will be taller Choose topicExperimental OrganizerDataLaboratory Report

6. Independent Variable (IV)  What will be purposefully changed by the experimenter. What you are testing. There is only ONE IV in a controlled experiment! EXAMPLE: Age of Compost Choose topicExperimental OrganizerDataLaboratory Report

7. Levels (Treatments) of IV  Specific changes that will be made to the IV.  One is the control: The standard for comparing experimental effects.  Specific changes that will be made to the IV.  One is the control: The standard for comparing experimental effects. EXAMPLE: Levels of I.V. (2 or more plus the control, which must be identified) 3 month old compost 6 month old compost No Compost (control) Choose topicExperimental OrganizerDataLaboratory Report

8. Number of Trials  Number of replications of each level/treatment.  At least 2 trials per level/treatment.  Number of replications of each level/treatment.  At least 2 trials per level/treatment. EXAMPLE: Choose topicExperimental OrganizerDataLaboratory Report

9. Dependent Variable (DV)  Variable that “depends” on the IV. Your RESULTS.  Specifically:  Quantitative Measurements: NUMBERS (Quantities)  Qualitative Measurements: CHARACTERISTICS (Qualities)  Variable that “depends” on the IV. Your RESULTS.  Specifically:  Quantitative Measurements: NUMBERS (Quantities)  Qualitative Measurements: CHARACTERISTICS (Qualities) EXAMPLE: Quantitative Measurements: Height of plants (cm) Qualitative Measurements: Plant Health description Choose topicExperimental OrganizerDataLaboratory Report

10. Constants  Procedures and materials used throughout experiment to assure there is only one Independent Variable. EXAMPLE: Amount of light, amount of water, amount of compost Choose topicExperimental OrganizerDataLaboratory Report

11.  The Experimental Organizer will help describe your experimental PROCEDURES in detail. Include:  MATERIALS  STATE IV, DV, CONSTANTS, ETC.  SET-UP PROCEDURES  DATA COLLECTION PROCEDURES  The Experimental Organizer will help describe your experimental PROCEDURES in detail. Include:  MATERIALS  STATE IV, DV, CONSTANTS, ETC.  SET-UP PROCEDURES  DATA COLLECTION PROCEDURES Choose topicExperimental OrganizerDataLaboratory Report Looking ahead: Use the Experimental Organizer to--among other things-- write your PROCEDURES in the EXPERIMENTAL DESIGN section of your Laboratory Report.

12. Data Tables  1. Make a table containing vertical columns for (1) the independent variable, (2) dependent variable and (3) statistical calculations (i.e. mean). Use a ruler. * are the cells of your table large enough?  2. Subdivide the column for the dependent variable to reflect the number of trials.  3. Under the I.V. column, list the levels (treatments) of the independent variable in rows – preferably from the smallest to the largest.  4. Title the data table (The Effect of I.V. on. D.V.)  5. Record all data values and calculations in the appropriate locations!  1. Make a table containing vertical columns for (1) the independent variable, (2) dependent variable and (3) statistical calculations (i.e. mean). Use a ruler. * are the cells of your table large enough?  2. Subdivide the column for the dependent variable to reflect the number of trials.  3. Under the I.V. column, list the levels (treatments) of the independent variable in rows – preferably from the smallest to the largest.  4. Title the data table (The Effect of I.V. on. D.V.)  5. Record all data values and calculations in the appropriate locations! EXAMPLE: Choose topicExperimental OrganizerDataLaboratory Report

13. Graphs  Use Data Tables to create Graphs  1.Identify dependant (y-axis) and independent (x- axis) variables (Y depends on X) the dependant variable is the variable you are measuring the independent variable is the variable you are testing - or the one that you are changing  2. Establish/calculate a scale for each axis what is the range for the data? how accurate do you need to be? what are my graph paper limitations (if any)?  3.Bar (DISCONTINUOUS data) or Line Graph (CONTINUOUS data)?  4.Label the x-axis and y-axis (designate units in parenthesis)  5.Title the graph: The Effect of Independent Variable on Dependent Variable (*same as data tables!)  Use Data Tables to create Graphs  1.Identify dependant (y-axis) and independent (x- axis) variables (Y depends on X) the dependant variable is the variable you are measuring the independent variable is the variable you are testing - or the one that you are changing  2. Establish/calculate a scale for each axis what is the range for the data? how accurate do you need to be? what are my graph paper limitations (if any)?  3.Bar (DISCONTINUOUS data) or Line Graph (CONTINUOUS data)?  4.Label the x-axis and y-axis (designate units in parenthesis)  5.Title the graph: The Effect of Independent Variable on Dependent Variable (*same as data tables!) Choose topicExperimental OrganizerDataLaboratory Report

14. Graphs  Use Data Tables to create Graphs  FOR QUALITATIVE DATA:  Frequency of MODE, or  Frequency of one or more of the dependent variables  Use Data Tables to create Graphs  FOR QUALITATIVE DATA:  Frequency of MODE, or  Frequency of one or more of the dependent variables Choose topicExperimental OrganizerDataLaboratory Report

15. Use your Experimental Organizer and other information to write a full Laboratory Report which includes:  A. TITLE  B. INTRODUCTION  C. HYPOTHESIS  D. EXPERIMENTAL DESIGN  E. DATA  F. DISCUSSION  G. CONCLUSION  H. REFERENCES CITED Use your Experimental Organizer and other information to write a full Laboratory Report which includes:  A. TITLE  B. INTRODUCTION  C. HYPOTHESIS  D. EXPERIMENTAL DESIGN  E. DATA  F. DISCUSSION  G. CONCLUSION  H. REFERENCES CITED Choose topicExperimental OrganizerDataLaboratory Report

16. A. Title  Use Title from Experimental Organizer. Choose topicExperimental OrganizerDataLaboratory Report

17. B. Introduction Conduct further research and write a complete Introduction. Stating:  BACKGROUND: WHAT  RATIONALE, PURPOSE: WHY do this experiment  explain HYPOTHESIS: HOW you expect it will turn out Conduct further research and write a complete Introduction. Stating:  BACKGROUND: WHAT  RATIONALE, PURPOSE: WHY do this experiment  explain HYPOTHESIS: HOW you expect it will turn out Choose topicExperimental OrganizerDataLaboratory Report

18. C. Hypothesis  Use Hypothesis from Experimental Organizer. Choose topicExperimental OrganizerDataLaboratory Report

19. D. Experimental Design  Using Experimental Organizer as a start, describe your experimental PROCEDURES in detail. Include:  MATERIALS  STATE IV, DV, CONSTANTS, ETC.  SET-UP PROCEDURES  DATA COLLECTION PROCEDURES  Using Experimental Organizer as a start, describe your experimental PROCEDURES in detail. Include:  MATERIALS  STATE IV, DV, CONSTANTS, ETC.  SET-UP PROCEDURES  DATA COLLECTION PROCEDURES Choose topicExperimental OrganizerDataLaboratory Report

20. E. Data  Include Data Tables and Graphs Choose topicExperimental OrganizerDataLaboratory Report

21. F. Discussion  Discuss data in detail: WHAT happened.  Identify trends and anomalies.  Explain WHY you got the results you did.  Compare findings with other research/results.  Suggest HOW to improve, further the study.  Discuss data in detail: WHAT happened.  Identify trends and anomalies.  Explain WHY you got the results you did.  Compare findings with other research/results.  Suggest HOW to improve, further the study. Choose topicExperimental OrganizerDataLaboratory Report

22. G. Conclusion  Restate purpose, summarize results in relation to Hypothesis. Choose topicExperimental OrganizerDataLaboratory Report

23. H. References Cited  List sources used. Choose topicExperimental OrganizerDataLaboratory Report