Experimental Description and Further Research

Due date for Homework #2: January 17, 2020 (Friday)

Part I

• Describe the experiment you’re thinking of running
• You need to list:
  • independent variables (I change)
  • dependent variables (what we measure; depends on what I change)
  • controlled variables (stays the same)
  • problem statement
    • Write the problem statement in terms of a question. A sample problem statement might be, " How does the amount of sun light affect the height of new plants." In this example, the height of plants would be the dependent variable and the amount of sunlight would be the independent variable.
  • hypotheses for the relationship between the Independent/Dependent variable pair (If...then...because).
    • see example below

Part II

Research your ideas and take bulleted notes from at least 3 more additional sources (a total of 6 resources for your topic)

• Take bulleted notes on a separate page for each source.
• Make sure to create an MLA formatted citation
• Use your own words!
• 1 of your 6 sources NEEDS to be a book source!

You should now have research from at least 6 sources (including at least one book)! Those sources will need to be cited on a Works Cited/Bibliography page at the end of the final report.

Definitions and an example:

Independent Variable (Cause): This variable causes something to happen to the dependent variable. The scientist changes the independent variable on purpose.

Dependent Variable (Effect): This variable has something happen to it as a result of the independent variable. The dependent variable changes in response to the independent variable. The dependent variable is the variable the scientist measures.

Control Variable: This variable stays constant throughout all of the experiments (so you can test the independent variable).

Problem Statement: Your experimental question

Hypothesis (If, then...because): This is a tentative, testable answer to a scientific question.

Example Part 1:

Problem Statement: How does the pH of water affect the rate of corrosion of iron nails?

Independent variable/cause: pH above 7.0, pH below 7.0, and pH 7.0

Dependent variable/effect: rate of rust on iron nails (Will iron nails rust faster or slower?)

Control variable: Time exposed to pH, time allowed to rust, location experiment is performed, all iron nails are the same kind

Hypothesis: If the pH is below 7.0, then the rate of corrosion will increase because the iron nail will experience more acidic conditions. Positive hydrogen ions in the acid remove electrons from iron, ionizing it and making it susceptible to rust. Above pH 7.0 will rust the slowest, pH 7.0 will rust next fastest, and below pH 7.0 will rust the fastest.