Chemistry Lab Report & Graphing Basics

Formatting Your Paper  Typed  Double spaced  12-pt Times New Roman font  Each section should be titled  Name date and period go in the upper right hand corner (do not include a title page)

Example Mrs. Canevit 9/11/2015 Period 4 My Lab Report Introduction Materials and Methods Data Results and Discussion Conclusion

Title  The title says what you did. It should be brief (aim for ten words or less) and describe the main point of the experiment or investigation. An example of a title would be: "Effects of Ultraviolet Light on Borax Crystal Growth Rate". If you can, begin your title using a keyword rather than an article like 'The' or 'A'.

Introduction  The introduction contains background information and explains the objectives or purpose of the lab. This is also where you state your hypothesis.

Materials and Method  This is where you write the steps you followed in paragraph form, citing specific directions and materials.

Data  Numerical data or observations that were obtained when the lab was performed. Display data in a well-organized fashion such as a data table. Data encompasses what you recorded when you conducted the experiment. It is just the facts, not any interpretation of what they mean.

Results & Discussion  This section describes in words what the data mean. The results and discussion section contains any calculations you made as well as any graphs that were used to show patterns in data. This is where you interpret the data and determine whether they support your hypothesis.

Conclusion  Restate the purpose of the lab, discuss whether or not the purpose of the lab was achieved, and what the outcome was. Discuss the possible sources of error (such as instrumentation problems, mistakes in execution or human errors in measurement etc.).

Graphing Basics  Graphs should be  Titled  X and Y-axis should be labeled  X and Y-axis should have a scale

Graphing Basics  When data are listed in a table, a pattern might not be obvious.  Using data to create a graph can help to reveal a pattern if one exists.

Circle Graphs  Also called a pie graph  Useful for showing parts of a fixed whole  Parts usually labeled as percents with the whole circle representing 100%

Bar Graphs  Used to show how a quantity varies across categories  Quantity being measured on y-axis  Independent variable on x-axis  Relative heights of bars show how the quantity varies

Line Graph  Points on a line graph represent the intersection of data fro two variables.  Independent variable plotted on x-axis  Dependent variable plotted on y-axis

Best-Fit Line  If data points do not fit perfectly, a line cannot pass exactly through all of the points  The line must be drawn so that about as many points fall above the line as fall below it

Relationships Between Variables  If the best-fit line for a set of data is straight, there is a linear relationship between the variables and the variables are said to be directly related.

Relationships Between Variables  If the best-fit line rises to the right, then the slope of the line is positive.  A positive slope indicates that the dependent variable increases as the independent variable increases.

Relationships Between Variables  If the best-fit line sinks to the right, then the slope of the line is negative.  A negative slope indicates that the dependent variable decreases as the independent variable increases.

Slope  You can use two pairs of data points to calculate the slope of the line.  When the mass of an object is plotted against its volume, the slope of the line represents the object’s density.