**3.2 Defining your problem**

[Workshop 1](/wiki/oil-testing-workshop-design-an-experiment), covered what is required in designing a scientific experiment. This workshop has presented how spectroscopy is used to detect oil in the environment. Now we will put these elements together. Below are options for what kinds of experiments are known to be possible with the current state of development on Public Lab’s spectrometer 3.0 and oil testing kit. Discuss as a group which topic you would like to design an experiment around:

* If you have an unknown substance you think might be oil, you can tell if the substance definitely isn’t oil.  
* If you have different oil samples, you can compare and contrast these samples (for example diesel, crude, fish, and motor oils).
* You can compare known oil samples with an unknown sample. You should be able to say if your unknown sample has a spectrum similar to or different from your known sample.
* You can compare oily materials to tell if they are similar or different.

After the group has chosen which experiment they would like to design, design a hypothesis (if needed, refresh your memory by reviewing Workshop 1: 2.3 and 2.4). Record the hypothesis on the large chart paper so that everyone can see it. Discuss as a large group. 

Return to small groups and work through designing the experiment. Ask yourselves, what needs to be done to test the hypothesis? Record the steps you specify for the experiment on the large chart paper. 
<div class="alert alert-info"><b>Facilitator’s heads-up:</b>Save this chart paper for use in Workshop 3.</div>