Contamination Lab
OBJECTIVE: TLW determining the meaning of collected data and its relevance to the question
being investigated and compare experimental results of peers and construct a reasoned argument
to justify conclusions while utilizing science safety procedures and investigating the effects of
cross contamination
BACKGROUND: Give an example how contamination has affected your life. Explain your
example and how it might have been prevented.
LABORATORY MATERIALS: Safety glasses, test tube, unknown solution, dropper/pipet,
phenolphthalein, 3 M NaOH solution, test tube rack, distilled water
PROCEDURES:
1) Each student will obtain a numbered test tube. Write down your unknown number in your
lab book and make observations on the unknown sample.
2) Using a pipet, the student will carefully trade about 10 drops of solution with 8 people.
While trading solutions, the student should keep an accurate record of who they traded with and
in what order they traded.
3) After trading solutions, 3 – 4 drops of phenolphthalein is added to each sample by the teacher.
4) Additional observations are made on the solution.