Purpose

This is a simple lab report that I created including tips on how to teach/help students identify the variables of an experiment. Typically, I teach this lab report the first time by actually walking students through an experiment and using guided questions to help them identify each section before officially defining it. Example - pose an experimental question, ask students what they think will happen, and THEN define their educated guesses as "the hypothesis". For our first experiment, we explore the impact of thumb size on the outcome of a thumb war. Students then use the report format throughout the year anytime we do an experiment, periodically to analyze given experiments for homework (to practice identifying variables), and as optional extra credit for home experiments. When using the format, students write on their own paper, but must include all sections clearly titled for easy grading. 

Lab Report Format

(Section: Explanation for students)

Question:  Why are we doing this experiment?

Hypothesis: What do you predict will be the outcome of this experiment? *

Procedure: Write down your experimental plan in five sentences or less. Be sure to tell how to set up the experiment as well as how to measure the results. **

Independent Variable: Identify the independent variable (Note: The IV is always found in the "if" portion of a caveman hypothesis.)*

Dependent Variable: Identify the dependent variable (Note: The DV is always found in the "then" portion of a caveman hypothesis.)*

Experimental Group: Describe the group that will be tested by receiving the independent variable treatment. ***

Control Group: This is a group that exists solely for comparison. Typically this group is identical to the experimental group except that it does not include the independent variable treatment. (No experimenting allowed here!) This way we can be sure that any changes in the experimental group were definitely caused by the IV. *** 

Constants: What things must be the same between the experimental and control groups so that any differences between them are sure to come from the independent variable only?

Results: Here is where we do the experiment! Write down any measurements, observations, and data that needs to be recorded in this section. Identify any data that you record as Qualitative or Quantitative. 

Conclusion: Carefully study your results. Did any patterns emerge? Was your hypothesis correct? What did you learn from this experiment? Why might it be a good idea to repeat this experiment? What new experiment might be inspired by this one? In this section, focus on what the results are communicating to you about the impact of the independent variable on the dependent variable. 

Teaching Tips

*Teaching tip 1: The Caveman Hypothesis. Note that while a hypothesis can be written in any format, encouraging students to convert it to "if/then" form can help them more easily define the causality of an experiment and identify independent and dependent variables. I take this a step further and teach my students to write a hypothesis in if/then format as if they were talking to a caveman or Tarzan (i.e. using as few words as possible). This makes the identification of the independent and dependent variables even easier and can help students wade through wordy experimental analyses by teaching them an effective way to simplify their reading and find the main idea. Cave man method example - The hypothesis "Adding fertilizer to my garden will help me grow more tomatoes" can be rewritten as "If I add fertilizer to my garden, then I will grow more tomatoes." While this change in format does help students better visualize the cause and effect aspect, reducing the hypothesis even further to 'caveman speak' forces students to identify the really critical components, thus revealing the independent and dependent variables. This hypothesis in caveman speak is "If fertilizer, then more tomatoes." "Fertilizer" is now easily identifiable as the independent variable, while "more tomatoes" is left to be the dependent variable.

**Teaching tip 2: Procedure. Limiting the students to only five sentences in this section saves time and helps teach them to communicate concisely. 

***Teaching tip 3: Controls. Teaching students to identify experimental controls has always been one of the more frustrating pieces of experimental designs. I finally figured out that understanding controls is all about the language I use when teaching. When I first start teaching this report format and experiments in general, I always use the full term "the control group" and define it alongside the experimental group (e.g. The Experimental Group here would be flowers with fertilizer. Therefore a good comparison Control Group would be flowers without fertilizer. This way you know that if the flowers in the experimental group are larger than the ones in the control group, the fertilizer made the difference.) Once the students have had some time and practice identifying both Experimental and Control groups together, they better understand the purpose of having the extra group for comparison. After enough practice, they automatically come to expect every experiment will have these side-by-side comparison groups. Gradually (over the course of several class periods), I will then start to drop the word "group" when talking about the control until eventually I can refer to the Control Group as just "the Control". By then, the students have associated the word control with the word group, so they still know what I'm referring to. In their mind, it's almost like I've simply created an abbreviation. It's very much semantics, but it really helps to prevent the confusion that often comes with mixing up controls and constants.